Help 2-NDFL / 03.10.2021

How to make a expansion joint extension. Types of foundation for an extension to the house. How to determine the width of the sole of the tape base

A frame extension to the main building is the easiest way to increase living space. In this way, you can build a living room, a technical room or a covered veranda. The main thing is to correctly connect the house and its extension.

Foundation selection and expansion joint

You should initially decide what the extension will be used for. This will determine the way the foundation, walls and roof are joined to the old house. This is a key point, because with different types of structures they will shrink differently, which can lead to cracks and distortion of the walls of the extension.

If a dwelling is planned, be it a kitchen or a bathroom, an extension to frame house should be of the same type - from the same materials, with floors and walls of the same thickness as the main building. If the main foundation is tape, then the new one is joined rigidly, with the help of driven reinforcement, and the formwork is installed close to the wall of the house.

This will allow not to close the contour of the foundation and not to organize an expansion joint around the entire perimeter. But with a rigid connection, the foundation must be very stable and not sag. Therefore, it is recommended to compact the soil well under the pillow, and make the pillow itself reinforced and 15 cm wider than the foundation tape. In this case, it is better to use crushed stone, not gravel.

If the weight of the extension and the building is very different, or a different type of foundation is chosen, it is imperative to organize an expansion joint. An extension can be made both in the shape of the letter P, without closing the contour, or by erecting all four walls.

In the first case, the expansion joint is made only at the junction of the house and the extension. This is the most convenient way do-it-yourself attachment connections. If the finished foundation is even and strictly vertical, the expansion joint can be made using a conventional roofing material - it will provide the possibility of vertical displacement of buildings.

Otherwise, it is better to use a thicker and more elastic material - polyethylene foam and polystyrene foam. The smoother the foundation, the smaller the thickness of the expansion joint. The smooth side of the sheets are placed on the new foundation. The outer part of the joint is filled with sealant and closed with an overlay that is attached only to the existing wall.

A four-sided foundation is needed in case of a risk of a strong displacement of the house and extension - with a significantly different weight, heaving soil or unstable foundation. Then, between the two buildings around the entire perimeter, an expansion joint 1-2.5 cm wide is made. In this case, the walls and roof should not be rigidly connected either.

The erection of walls and their docking with the house

If the house and the extension stand on the same foundation and are framed, building walls will not be a problem. The cross section of the bars is selected depending on the thickness of the insulation. For example, if a sheet of mineral wool is 15 cm thick, then the bars must also be selected with the same section of one of the sides. The main thing is not to confuse which side to attach them to the harness.

The walls are built in the following order:

1. The lower trim is laid on the foundation. Between the wood and concrete, you need to lay waterproofing - roofing material or foamed polyethylene. The strapping is screwed with ordinary dowels, and the corners are connected “in half a tree”.

2. If the extension is rigidly attached to the walls of the house, then the vertical bars are simply nailed to the walls, previously leveled. If not, then corner posts are installed first, which can be fixed with temporary slopes.

It is better to make the connection of the strapping and the beams with a complete cutting and additionally fix it with metal corners.

3. It is important to choose the right height of the vertical bars - whether the extension will be under a common roof or under a separate one.

4. The top harness allows you to strengthen the frame and remove temporary cuts. The bars of the upper trim are connected to the vertical ones in the same way as the lower.

5. After that, you can choose a place for windows and / or doors. Additional racks are attached along the width of the openings and horizontal lintels are nailed - along the height of the window and door.

6. Vertical bars are added in increments of 1 cm less than the selected insulation - it should lie as tightly as possible. You can also add horizontal jumpers that will strengthen the entire structure - the distance between them is also 1 cm less than the height of the insulation if it is supplied in sheets rather than rolls.

It is important to remember - when using glued beams, windows and doors cannot be inserted immediately. The design may shrink. The sheathing of the assembled frame is made after the installation of the roof.

Sometimes the frame of the extension to the house is assembled separately, installing whole blocks on the lower trim at once. This is very convenient for large structures - there is no need to fasten each vertical beam with temporary cuts and constantly work at a height.

The expansion joint should be arranged along the entire attached wall, if the foundation is with a closed contour, or only at the junction of the walls of the house and the extension. The requirements for it are the same as for the seam of the foundation - an elastic sealant is used inside, and the outer edge is treated with a sealant.

The rafters of the extension are laid with their lower end on the upper harness, and with the upper end they are connected to the roof rafters or rest on a run nailed to the wall of the house. If the rafters are rigidly connected to the extension wall, the roof may not withstand the shrinkage - the upper fasteners will break. Or the wall of the extension will begin to slope inward. Therefore, it is better to use movable joints for the free movement of the lower support.

For a roof with insulation, in addition to the horizontal lathing, a vertical counter lathing is also made, as well as an additional lathing on the inside. If a metal tile is used, it can be laid immediately on the crate, and for soft tiles, a moisture-resistant OSB board is mounted on the crate.

In the first case, the wall of the house is covered with a galvanized apron, bent at an angle and fixed on top of the roof of the extension. This will protect the wall from rain, and the roofing cake from moisture.

In the second case, the roof will be common and it will have to be completely rebuilt.

Wall cladding and insulation

After the installation of the roof, you can proceed to the sheathing of the walls. Despite the popular advice to first sheathe the walls with boards or OSB sheets for structural strength, it is much more convenient to do this under the roof. First, the extension is sheathed from the outside.

If not glued timber was used, then windows and doors are installed at the same stage. It is better to order a double-glazed window ready-made - with a double chamber for better thermal insulation. If you plan to install a door, it is better to hang it immediately. The second rack fits under the door. Installing windows and doors before insulation allows you to fit horizontal lintels and racks as tightly as possible to the openings.

After the outer skin, insulation is laid and the extension is sheathed from the inside. You can use the same OSB boards, drywall or lining. At the same stage, the roof is insulated - waterproofing, insulation and vapor barrier are laid under the crate. An additional crate and inner lining are mounted on top.

For living quarters, it is necessary to insulate the extension also from the outside. The easiest way is foam boards, which are mounted on the wall with mounting foam and screwed with self-tapping screws.

To prevent self-tapping screws from falling into the foam, rectangular or round spacers are used. Another trick is to make the window slopes even, the plates are attached to the window frame with the side with factory cuts and with a slight overlap.

Door slopes can be damaged during operation, therefore, around the perimeter of the door, it is better to screw a beam as thick as a heater onto the screws. The ebb on the window can be attached with mounting foam, it also fills all the cracks. After that, a reinforcing mesh and a reinforcing solution are laid on the foam, and all corners are reinforced with metal corners.

Floor device in a frame extension

The floor for a small extension on a strip foundation could be filled with a cement-sand screed. To do this, the entire perimeter inside the foundation was covered with brick rubble and rammed. Tiles can be laid on top of such a floor - best option for technical rooms.

If a dwelling is planned, or a columnar foundation is chosen, it is best to arrange a wooden floor on logs.

For a strip foundation, the space under the floor should be insulated. The soil is selected to a depth of up to 25 cm and a layer of rubble is first poured into the resulting pit, tamped, a layer of sand is poured on top, moistened and tamped again. Brick columns are placed on the resulting pillow - the logs will rest on them.

The advantage of the floor on the logs is its layering. Between the rough and finish floor there is a layer in which the insulation is placed. This allows you to make a really warm floor, on which you do not have to walk with shoes on.

The video provides a detailed overview of the finished frame extension to the house:

Increasing the usable area in private ownership by adding new premises that stand on their own foundation begins with solving the problem of how to connect the foundation to the house so as not to harm both structures. The erection of additional structures usually begins after several seasonal cycles during which the accumulation has occurred. financial resources, there was a desire for a new round of arranging the site, standing buildings gave normal shrinkage in the ground. building codes give an answer on how to connect the two foundations with each other, taking into account mutual influence.

Connection Requirements

Decide how to tie new foundation extensions with a residential building, it is necessary at the design stage, taking into account already existing factors. These include the following conditions:

type and design indicators of the foundation of the existing building;
characteristics of underlying soils;
the time elapsed since the previous construction (the main shrinkage occurs in 1 - 2 years);
commensurability of the weight load of 2 structures to be combined.

The complete requirements for the calculation are contained in the set of rules SP 50-101-2004, which was developed in the development of the regulatory rules contained in SNiP 2.02.01-83*, SNiP 3.02.01-87.

In any case, the help of experienced professionals is not superfluous, since mistakes can cost a lot later.

The result of linking the base and attached building structures with different shrinkage values of the bases is shown in this video

The construction of a new building begins depending on the season. In the spring, it is not recommended to start laying next to the already standing foundations, since at this time of the year the soils are in the most loose and watered state. The settlement value of a new extension on heaving soil may be much greater than the calculated value in the project, and be uneven around the perimeter. At the same time, there is a risk of movement of the undermined old support due to the high level ground water combined with possible precipitation (rain or snow).

Before starting work, it must be taken into account that any new foundation (MZLF, piles, poles, slab) will definitely settle, even if it is made identical to the existing support.

Shrinkage

In construction, there are established settlement standards for various structures, the foundations of which are designed and manufactured in accordance with the current state standards.

You can find out the standard and make a forecast for the design of your individual house according to the data from the reference tables:

When comparing the calculated indicators, a new support unit is attached to the foundation of the old building at a given depth, taking into account its own settlement after a certain time.

The upper marks of the monolithic strip foundations of the combined buildings are carried out according to the calculation, and not according to the level, as in this photo.

It is the possibility of displacement relative to each other that determines which connection of the two foundations can be made. The following types of connections are used:

Rigid bond (reinforced concrete).
Separate installation (device of an expansion joint, taking into account the mutual influence of the supports).

The possibility of a rigid connection into a single structure is significantly influenced by the geological factors of the site - with moving or heterogeneous soils for buildings with a large area of \u200b\u200bsupport, it is necessary to make intermittent foundations (sometimes with different tape widths).

The start of independent construction of a new module of an extension to a residential building is permissible if the following requirements are met: issue permits for the installation of a new structure, maintain distances not closer than the minimum allowable to nearby buildings and communications, ensure an independent draft of all structures in relation to each other.

Combining Foundations

The new room is best attached to the existing foundation of the house with a rigid hitch. In this case (with the correct consideration of all conditions), it is possible to connect the above-ground surfaces into a single whole without the expectation that cracks and distortions will appear between the elements, the floor level. But such a design solution is limited to sites with non-rocky soils that have high bearing characteristics.

In practice, this method is used for low-rise buildings, provided that the extension being built is functionally connected by one roof to the building already in operation.

Another condition for combining is the same type of foundation. If a residential building has a strip base that is not wide enough, then it is necessary to strengthen it.

Such work includes joining the reinforcement of the old support with the new frame or laying the connecting anchors by drilling, then pouring the belt with branded concrete. The reinforcing belt prepared for the application of the solution is shown in this photo.

The connection of buildings consisting of several floors is carried out according to a more complex scheme, involving the installation of covering walls with separating seams on each side, as shown in the drawing.

The rigid type of connection is chosen for cases when the task is considered, how to connect the old well-established foundation with the new structure, for buried strip foundations. The extension is also designed as a monolithic reinforced concrete structure.

Strip foundations

For a capital building attached to a house, having a commensurate weight of the building materials used, a stable support of a large area and bearing capacity is necessary. Such a request corresponds in most cases to a strip foundation.

Expose the existing tape to its full depth. It is necessary to dig a trench in parts (1.5 m - 2 m), not along the entire length at the same time, since the bare part loses its lateral support, which can lead to its deformation. The old building can be further strengthened with inclined supports.
Drill holes on the side of the connection, corresponding in size to the Ø of the reinforcement. In the middle of the tape, holes are drilled in a checkerboard pattern with a depth of about 0.75 of the width of the foundation itself, in the corners - 0.5 m. Reinforcement is driven into the middle holes, in which longitudinal slots are made with an inserted wedging insert for strong fastening in the hole. Reinforcement Ø 14 mm, having a periodic profile, is hammered into the corner holes. The release of bars should be at least 0.3 - 0.4 m.
The frame of the new foundation is knitted with its welding to the released reinforcement.
Filled with concrete.

If there is access to the subfloor for carrying out work, the holes for the tightening elements of the stud type can be made through with the fixation of the rods with flat plates.

Rigid connections of tapes in the form of an open loop (P - shaped) are made in the same way, but the reinforcement is placed with a smaller step in rows. With a large length of the connection side in an open tape, several additional support points can be made differently from the monolith, as can be seen in the photo.

If it becomes necessary to change the depth of support on the soil of the attached foundation, it is poured with ledges, the height of which varies in steps of no more than 0.5 m. The first ledge is located at a distance of about 1 m from the old foundation. The connection is made with a reinforced concrete strip of the same thickness as the existing foundation of the house.

Each option for a rigid connection of foundations has its own characteristics for specific cases, which it is advisable to entrust to professionals to consider and calculate.

Plates

It is possible to ensure the rigidity of the connection of the slab foundations of the house and the extension, provided that they are of a sufficiently large thickness of about 0.4 m, as well as with the existing protrusion of the old slab beyond the boundaries of the supporting walls of the building. Such protrusions, as a rule, are left during the construction of aerated concrete cottages. The dimensions of the outlet should be at least 0.3 m. This will make it possible to clean the reinforcing mesh of the slab and make welded joint with the frame of a new extension.

A bunch of monolithic bases is performed according to the following scheme:

The slab of the old house, which has already precipitated, in this case not only becomes one with the new fill, but also receives additional reinforcement along the vertical connection of cement mortars due to the addition of 0.2 m - 0.3 m under it.

Separate supports

With a large discrepancy in the weight of the old and new structures, the degree of shrinkage of these structures will differ significantly in magnitude. In such cases, it is not recommended to make a rigid binding for foundations - it is necessary to choose separate construction of supporting elements. It is allowed to attach other types of foundation to the existing base and for this use the principle of connection through an expansion joint.

The distribution of the weight of the ceilings and walls of the extension should occur on its own support area, without creating tearing forces for the main foundation of the building.

The expansion joint, depending on the operating conditions, can be:

sedimentary;
temperature;
seismic.

The sedimentary variant (in the absence of other significant influences) has a width of 1–2 cm. bearing wall old house can be performed with a deformation gap reaching 0.2 - 0.4 m, filled with an elastic moisture-proof material.

Frame wooden extensions successfully operated on a pile foundation with a metal grillage, as in this photo.

Light verandas or summer kitchens can be attached to screw piles, even if there are already several adjacent buildings around. This is especially convenient if the site is located on a slope, slope, or with an uneven occurrence of solid supporting rocks.

At the design stage, they provide for the external design of expansion joints that visually separate the facade, in an open or hidden form, for example, hiding a gap with a subvertical downpipe. On the front side, they are usually covered with strips of a special flashing, sealed decorative material low strength, which will not prevent the displacement relative to each other of the outer walls of buildings with a possible uneven settlement. Under the roofing, the gaps are closed with the help of a compensating device.

An extension to a house, installed on supports separate from it, is a much less laborious process than a rigid tie, it requires significantly less time and financial costs, and also available to do it yourself without ordering special equipment

A far-sighted decision is to provide for the possibility of an extension at the design stage of the main building of a private house. This will greatly simplify the subsequent execution of work and will contain ready-made design solutions, a planned uniform settlement over the entire laying area and ensure the reliability of the foundation made.

kakfundament.ru

Thanks for the detailed information, Max. Detailed presentation technical side The question was very helpful for our experts to make recommendations for you. We hope our answer is helpful.

In order:

"How to make a joint for joining two foundations?"

Let's start with the foundation design. There are two constructive options for making an extension to the house:

Option 1

Rigidly connect the extension to the main part of the building. For this, the foundation of the extension must have a structure similar to the existing one, that is, it must be tape with sufficient depth. At a minimum, the base pad of the new foundation should be located below the freezing depth of the soil. In this case, both the foundation and the walls can be connected with reinforcement by driving it into pre-drilled holes in the existing walls. In this case, the expansion joint is not needed, the formwork for the strip foundation can be installed close to the existing one, the expanded clay concrete blocks are laid end-to-end on the mortar. It would be desirable to cut a recess in the existing blocks at least 10 cm in a couple of places along the height and lay the laying of new walls there. The difference in the height of both parts of the building is small, the loads will not differ very much. With a rigid docking of the extension with the house, it is necessary to pay maximum attention to the reliability of the foundation, its subsidence should be excluded. You write that “the soil is not problematic”, this is good. Under the tape, you need to build a reinforced support pad about 20 cm high, 10-15 cm wider than the tape on both sides. The soil under the pillow must have its original density, bulk soil is not allowed. We recommend making a crushed stone (not gravel) bedding about 15 cm thick and compacting it properly. Such a solution will make it possible to make a general floor screed, without worrying about the expansion joint, there will also be no seams in the walls.

This video shows how to rigidly tie parts of the foundation of a building that are being built at different times with reinforcement.

Option 2

The construction of the foundation of the extension differs markedly from the main volume; an expansion joint is made between them. Both parts of the building can have noticeably different shrinkage and this will not cause damage to the structure. This solution is optimal when constructing a pile-grillage foundation, which you probably chose because of its cost-effectiveness. Piles, having a smaller area of support compared to the pillow of the tape, will sink deeper than the tape structure.

Please note: when erecting piles, try to ensure the largest possible area of their bearing on the ground, this minimizes the subsidence of the foundation of the extension. For drilling wells for piles, it is advisable to use a TISE drill, in many cities their rental is organized.

How to fill the expansion joint in the foundation? Since the dimensions of the house are small, thermal deformations characteristic of large buildings can be neglected. The house is small, with a well-made foundation of the extension, only its vertical displacement is possible. There is no need for a wide expansion joint, it is sedimentary, not temperature. If the formwork of the existing foundation is carefully made, its surface is even and strictly vertical, when topping up the foundation, any thin material can be laid between the existing and new parts that will not interfere with vertical movement. For example, a strip of rolled bituminous waterproofing: roofing material or its modern counterpart.

If the surface of the existing foundation is uneven, it will be necessary to fill the seam with an elastic material, the thickness of which will be sufficient to compensate for the unevenness. Neither a tarred board nor tow should be used, because it is organic matter that will quickly collapse in the ground. In addition, the board will swell, jamming the seam. And how to fill the entire depth of the joint with tow, we can’t even imagine. Today there is a sufficient number of durable, non-rotten and non-absorbent sheet elastic materials. For example, foamed polyethylene. Or expanded polystyrene, on sale there are sheets with a thickness of 1 to 5 cm, the size is a multiple of a centimeter. The thickness should be chosen depending on the degree of unevenness of the foundation. If necessary, if there are significant irregularities on the existing foundation or the slope is large, the expanded polystyrene sheet can be cut with a knife or melted with a building dryer. The smooth side of the sheet should be turned towards the new foundation, trying to install it vertically.

Thus, the joint between the two parts of the foundation is filled with sheet or rolled relatively soft material. The sealant that you are advised is to fill the outer part of the joint to a depth of 1-1.5 cm. The function of the sealant is to seal the joint, sorry for the tautology. If the gap is wide enough, it can be filled with construction foam. But after the excess foam is cut off, it should also be covered with a layer of sealant. For the foundation, any type of building sealant is suitable, except for acrylic.

“Is it enough ... a U-shaped foundation, or do you need to fill in four walls?”

Probably, you meant the following: is it enough to build a foundation only along the outer contour of the extension, or does it need to be closed, the bay also has a grillage around the entire perimeter, including near the existing part of the building? If we guessed the essence of the question, we answer: enough, not necessary. The foundation serves to support the load-bearing walls, only under them it makes sense to build it. Your drawing shows a new pile-grillage foundation and, along the existing one, either a monolithic or prefabricated reinforced concrete slab rests on it. But two hollow-core slabs with a length of 5380 mm can be perfectly supported on two short extension walls. And for monolithic floor make one or two intermediate pile supports instead of a full-fledged grillage.

Please note: the piles closest to the existing part of the building supporting the grillage should be located as close as possible to the old foundation. The distance is the minimum that the TISE drill will allow, taking into account its expansion under the support platform.

“How to make a high-quality wall joint?”

Let's rephrase your question: how to fill the expansion joint in the wall? We use the same principles as in the construction of the foundation: roll / sheet / slab material inside and sealant outside. We hope that the walls of the house are quite even, so thin (2-3 mm) polyethylene foam, cork sheet or other warm non-rotting material can be laid between the blocks. From the inside, “seal” the seam with acrylic sealant, plaster and putty will lie well on it. Outside, if you plaster the wall - also with acrylic, if you leave the blocks without finishing - with silicone, it can be matched to the color of the walls.

There are also a number of special materials for filling expansion joints. Among them, we especially note swelling cords made of hydrophilic rubber (for walls) and swelling bentonite profiles (for foundations). Cords are intended to fill the outer part of the joint, they are used instead of sealant. These are excellent professional materials, specially designed for sealing joints. However, they are quite expensive and are not sold in retail chains. You will have to look for a supplier company, but there are not so many of them. There will be an opportunity - use them, no - simpler and cheaper solutions described above are also suitable for your case. Another type of special materials for seams is overlays. They are useful if, as a result of deformations, the seam diverges. The patch closes the gap. In your case, we do not recommend installing such an overlay. If the seam still breaks, it is better to refill it with sealant.

You write "blocks on an existing foundation lie with a protrusion of 10 cm outward." It's not a problem. Make a horizontal expansion joint on this 10 cm section. If you deepen the foundation of the extension, as expected, below the freezing depth, it will not rise after the winter. For the next season, check the condition of the seam, if necessary, renew the sealant, if a noticeable gap forms, fill it with construction foam.

It makes sense to take care to exclude horizontal displacement of the extension walls adjacent to the main building. The dimensions of the house are small, such a deformation is unlikely to occur, but if you decide to give the structure additional reliability, you can reinforce them in the upper part of the wall joint. Fix the reinforcement rigidly in the existing wall, and place it in the extension in a vertical gate

“So, you need to make two separate floor screeds in the old and new parts of the living room?”

If the foundation will be made according to option 1 (rigidly connected and without an expansion joint), and the floor in the extension is located on a reinforced concrete slab, as in the main part of the house, there is no need for an expansion joint in the floor. You can monolithic a common screed. In other cases, an expansion joint should be made in the floor. And it doesn’t matter if the new floor is resting on the slab, or you decide, having saved money, to build it on the ground, making a backfill in the extension. The seam must necessarily penetrate through the entire floor structure from top to bottom. Including coverage. If it is a tile, try to lay it out in such a way that the seams in the tile coincide with the deformation. It doesn’t work - you have to cut the seam right in the tile and fill it with a silicone sealant matched to the color. In massive parquet or floor boards, the seam can also be filled with sealant. In floating floors (laminate, parquet), you will have to close the gap with an overlay.

"What other moments might come up?"

Be sure to "float" the roof. From below, the rafters will rest on the wall of the extension. And from above, based on the drawings you sent - to the existing wall of the house. If you complete the foundation according to the second option, when the extension sags, the mark of the lower support will go down. If the rafter legs are fixed rigidly, with noticeable subsidence, annoying troubles are possible: the upper mount will be torn off or the wall of the extension will be pulled inward at the bottom. To avoid this, it is necessary to allow free movement of the lower support. This issue is completely solved by the sliding structure of supporting the rafter legs.

blocks-tiles.rf

Perhaps there is no problem. An expansion joint is arranged in cases where uneven shrinkage of the building is likely. This can happen due to the very large dimensions of the structure, a significant difference in the heights of individual sections of the house, the possibility of subsidence of foundations and soils.

If you are not building in a seismic area, your house is stone or frame, no higher than two floors and has a reasonable size, it is really possible to do without a seam. It is enough to build a solid foundation under the extension. Structurally, it should be identical to the existing part, laid to the same depth. If the foundation is tape, it is important to compact the base well under its pillow, sprinkle the bottom of the trench with crushed stone, and carefully compact it. The old and new parts should be connected to each other by hammering reinforcing "ruffs" into the concrete, having previously drilled holes for them.

The walls of both parts of the building must also be connected to each other.

If there is no confidence in the bearing capacity of the soil, or the extension is log and will shrink, an expansion joint will have to be done. You did not indicate any features of the construction of the house (the material of the walls of the main part of the house and the extension), nor the nature of the junction (flat plane, corner). The design of the seam depends on the specific situation, there can be a lot of options. Without the necessary information, we can only give general recommendations:

If there is a possibility of significant shrinkage of the extension relative to the house, best solution will install not three, but four walls, including the one adjacent to the existing one. The foundation and walls of the extension will have a closed contour, which will exclude horizontal deformations, in the second illustration this is option D.
The thickness of the expansion joint in our case is 10-25 mm, it can be filled with rigid mineral wool, foam plastic, foamed polyethylene.
The roof of the extension must also be completely separated from the old part of the building. The junction can be closed with an apron, fixing it on the wall.

The junction of the walls of the old and new parts of the house, located in the same plane, should be closed with an overlay (wooden board, metal plank), which should be fixed to the existing wall.

If you are attaching a three-walled wooden log house, the joint should be made with a straight key cut or on the casing: a bar (thorn) should be located on the existing wall, a groove is selected in the attached wall. The annex, losing moisture, will settle along the guide, which prevents the logs from torsion. Nails, staples are not used, the seam is filled with traditional insulation: moss, tow, jute. Outside, a board-overlay is installed.

strmnt.com

A feature of the foundation for an extension is the need for reliable docking of a new foundation with an existing one. There are only two main options - either to connect the old and new foundations rigidly, using steel reinforcement as connections, or to use a simpler and less expensive connection of two foundations - by arranging an expansion joint between them.

The first rigid docking method gives a foundation that will work as a whole, and therefore it is possible to use it only in cases where the existing foundation has passed the settlement stage, and the new foundation will not cause additional settlements greater than the allowable value. The second condition is that the rigid joining of the old and new foundations will be reliable only in cases where the soil at the base of the house is not heaving.

Rigid connection technology for foundations

Before designing a new foundation, you need to decide on the old one - determine its type, size and depth. If these parameters are not known, they must be determined by careful excavation. The depth of the foundation is determined by pitting.

One of the main conditions is that the depth of the new foundation should be greater than the depth of the existing one. It is clear that different types foundations perceive the movement of soils during heaving in different ways, so the foundation for the extension must be of the same type as the main one, regardless of the material and type of extension structures. The extension, as a rule, is made of materials lighter than those of which the bearing structures the main building - foam blocks, gas blocks, wood or wood concrete. But regardless of the type of extension material, the new foundation must have a greater depth than the existing one.

Rigid docking of the old and new foundations is done with steel reinforcement anchors. The existing foundation is drilled, the diameter of the holes should be slightly larger than the diameter of the docking reinforcing anchors. The depth of the joint must be at least 35 diameters of the reinforcement entering the body of the old foundation, plus double the length of the rod to enter the new foundation, this length is considered working. If the width of the existing foundation is not enough to comply with this rule for the working length of the joint, then the joint rods are installed in the body of the old foundation like anchors with wedging inserts, which ensures reliable fastening of the reinforcement inside the concrete.

The number of reinforcing anchors must be at least five per ¼ m2 of the vertical area of the junction of the old and new foundations. reinforcing bars are cut to the specified size and installed in the drilled holes. Washers are welded at the ends of the rods. When concreting a new foundation, all additional reinforcement must be located in the body of the new foundation, in compliance with the protective layer.

stroyfora.ru

Often the owners of small country houses or cottages decide to complete the construction of a porch, a warm bathroom, a garage, a bathhouse or a kitchen. Using blocks of foam concrete, you can quickly, simply and inexpensively build an extension. If the structure has served for about two years and the foundation is well established, it is allowed to use the reinforced method of connecting the foundations of the house and the extension, the material of which is lightweight foam blocks.

But the method of using separate foundations is safer and cheaper. For a building to be reliable, its foundation must experience a uniform load. Attention: reinforced connection of two foundations is unacceptable if the extension and the house are different in number of storeys. Then the foundations will carry different loads, and the uneven deformation of the soil under them will lead to the appearance of cracks and deformations in the structures of the house and extension.

The purpose of the expansion joint is to minimize the influence of various loads on the walls of the extension and the house, to join structures with separate foundations to each other. The free space from the walls of buildings should be about 5 cm.

Expansion joint technology

1 . To get a gap between the foundations of about 5 cm, we separate the house from the future extension with several boards wrapped in plastic wrap (roofing material can be used). At the end of the work, they can be left, it is not necessary to delete them.

2 . For an extension, the material of which is foam blocks, you can use a strip foundation. According to the construction technology, the level of the foundation (the sole of the foundation) must be below the soil freezing limit. If the land plot is characterized by very unstable (heaving) soil, perform the foundation of the extension just below the foundation of the house to avoid deformation during shrinkage. Strip foundation, the extension walls are performed according to the technologies described by us in previous articles.

3 . When the foundation, walls of the extension and the roof are ready, they are docked with the house with an expansion joint. To avoid the appearance of condensate, moisture, the seam space is filled with a special sealant. It can be polyethylene foam, mineral wool, polyurethane foam.

4 . All visible cracks are additionally filled with mounting foam.

5 . The finished sealant is fixed with a reinforcing rod between the house and the extension. The rod performs only the function of fastening the seal (so that it does not slip). The depth of entry of the rod into the foundations does not matter.

6 . To protect against moisture ingress from the outside, the expansion joint is closed with special flashings, which are attached to the walls of the house and extension.

7 . Special attention given to waterproofing. Water, snow from the roof of the house will fall on the extension. Therefore, its roof should have a sufficiently sloping shape so that moisture does not accumulate.

8 . In places where the building adjoins the house, galvanized corners are installed under the roof to protect against possible leaks.

9 . The exterior decoration of the extension, as a rule, is identical to the design of the old house.

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Why and how expansion joints are made in concrete: an overview of technology, types of joints and a step-by-step scheme of work

Since today the price of all building materials is constantly increasing, it is necessary to think about how to make truly high-quality structures so that later you do not have to constantly correct defects.

All kinds of concrete structures are no exception - for example, floors and blind areas around the building. If the floors are done incorrectly, they will simply crack, and this will automatically lead to deformation of the finished floor covering.

Photo showing temperature lines in the structure of a concrete floor

As for the blind area, it is, in fact, responsible for the integrity and normal condition of the foundation tape. If cracks appear in the blind area, then water will penetrate there, which in turn will fall into the structure of the foundation. And this is already fraught with serious consequences.

To minimize the risk of cracking, an expansion joint is arranged in concrete according to SNIP - with its presence, deformation is unlikely.

In fact, these are kind of cuts in the concrete structure, thanks to which the concrete does not crack during temperature changes - as it seems to have room to expand.

Correctly made blind area

In fact, there is a whole classification of protective lines - and there are not only temperature ones. Let's consider what they generally are, and then, using the example of installing floors and blind areas, we will figure out how expansion joints are arranged in reinforced concrete structures.

Types of seams in concrete

After the entire mass has solidified, the shrinkage incision is closed.

Such is the classification.

Please note that the installation of expansion joints in concrete implies their mandatory processing - these are not voids. As a rule, such cuts are sealed either with sealants, or with special profiles or elastic inserts. If this is not done, then the visual appearance deteriorates significantly and, of course, the thermal insulation qualities of the structure are lost.

Filling the deformation line with a special profile

Now we can move on to how exactly such temperature protection is done.

Installation of expansion joints

As already mentioned, we will get acquainted with the technology using the example of concrete floors and blind areas around the perimeter of the building. Why these structures? Because in most cases they are made with their own hands and with characteristic mistakes (see also the article “Grid for concrete - types and applications”).

And the errors just lie in the fact that there is no protective temperature line.

Screed without protective cuts

Before starting, a few words about the features of these structures, in which cases they need to be protected by such technology.

In addition, incisions must also be made along the perimeter of the columns (if any) at the points of contact with the floor.

Please note that the installation of expansion joints in concrete is also carried out in the walls. And even if they are not made of a monolith, but also of ordinary bricks or blocks.

Now you can proceed directly to work. Brief instructions for pouring the floor and blind areas, in which the focus will be on the installation of seams.

This element of the house is done like this:

A trench about 15 cm deep is made around the perimeter of the building.. At the same time, its width must be no less than the protrusion of the visors on the roof.
The trench is covered with rubble, strips of roofing material are laid on top of the stone.
Mounted reinforcement frame.Advice: reinforcement bars must be inserted into the walls of the house. To do this, such work as diamond drilling of holes in concrete is performed, into which the ends of the reinforcement are inserted.
A layer of concrete is poured with a slope from the walls.The expansion joint is made just before pouring concrete mix. It is done along the line connecting the walls and the blind area. In order to organize such seams, you just need to insert not very thick boards between the plane of the walls and the blind area. In addition, the seams are also made across the blind area - in the same way (using boards placed on edge). In this case, the distance between the expansion joints in reinforced concrete of this type should be approximately 1.5 - 2 meters.

Formwork for the blind area, taking into account temperature protection

It turns out that the mixture will flood the entire space, except for those lines where the boards are installed. After the concrete has cured, the boards are removed and the gaps filled with either sealant or polyethylene foam tape.

The main thing here is to make sure that the connection between the house and the blind area does not turn out to be empty - otherwise water will penetrate into it and, accordingly, there will be no sense from this design.

Now let's move on to the installation of floors with seams.

Seams in concrete floors

We will not consider the order of pouring the concrete floor, since expansion joints on such a plane can be arranged after the initial solidification of the mixture.

Of course, it is better to do this before pouring, so that cracks do not appear on the surface when the concrete dries, but, in principle, this is not necessary if protective lines are made before the concrete has hardened 100%. As a rule, complete solidification occurs in a few weeks - during this time you can have time to make seams, agree.

Safety notch in concrete

So, how are the seams in the screed.
The lines along which reinforced concrete will be cut with diamond wheels are determined. The distance between them is calculated using a very simple formula - we multiply 25 by the thickness of the screed, for example, it will be 10 cm. Accordingly, the distance between parallel lines should be about 2.5 meters.
The grinder cuts the seams, the depth of which should be equal to approximately 1/3 of the total thickness of the screed. As for the width of the lines, the optimal figure is a maximum of a few centimeters.
All dirt and dust is removed from the seams with the help of brushes and a vacuum cleaner, and then the entire space is primed.
After the primer has dried, the entire cut space is filled with mastic, sealant, or some kind of elastic material. In addition, there are also special profiles that are designed for laying in such seams. What we got as a result is that now, if the concrete mass expands, deformation will occur at the edges of the screed, along the lines where the seams pass. In these places, the extreme lines of concrete will crack a little at most, but the main floor finish will remain completely intact and unharmed.

Stitches close up

Which, of course, will save you money, since you will not need to spend money on current repairs.

Actually, our review of this technology is over, and now we can summarize.

It turns out that arranging expansion joints in the structure of concrete outdoors and indoors is a very desirable measure, as a result of which the general term service of the entire structure as a whole.

It turns out that having once invested in the installation of such expansion joints in concrete, you also save on minor current repairs.

We have figured out what kind of protective expansion joints are and how protection against exposure to different temperatures is arranged. We hope that the instruction will be useful to you in practice.

Sooner or later many owners suburban real estate decide to increase living space by adding to the house. In order for the connection of the main house with the extension to occur without problems, it is important to achieve a reliable and durable connection of the bases. As practice shows, there are two main ways to attach the extension foundation to an existing house foundation:

rigid connection using reinforcement;
expansion joint.

Each of the options for connecting the main foundation with the base of the extension has its own characteristics and nuances, which should be considered more thoroughly.

Most often, a rigid connection of the foundation of the main building to the extension is used on soils that are not subject to heaving. Most often, this method is used in the process low-rise construction in situations where the extension is functionally connected with an existing building and is under the same roof with it.

To make a base for an extension, a special hole is drilled in it to a depth of about 35 cm. Its diameter should be equal to the diameter of the reinforcement that will be used for clogging. If the extension is built according to a scheme that assumes the estimated length of the reinforcement is greater than the width of the foundation, holes in the base of an existing house are drilled only for part of the width. In this case, the fittings are mounted according to the anchor principle.

If the contour is planned to be closed, holes should be made at two levels and in a checkerboard pattern. As for the reinforcement, it must necessarily have an anchor wedging at one end and a welded washer at the other.

A rigid connection is also used in situations where the house has a recessed strip base, and the construction of an extension is planned from monolithic reinforced concrete.

The foundation with a rigid base can be in two versions:

tape-tape;
plate-plate.

When installing such a foundation, the following list of works is expected to be performed:

dig a trench, the depth of which corresponds to the already existing foundation of the main building;
fill the bottom of the trench with sand (create a sand cushion) and compact;
drill holes in the base;
drive reinforcing bars with a longitudinal slot into pre-prepared holes;
insert a wedged insert (for example, made of wood) into the reinforcement slot;
drive the reinforcement into the holes at the corners of the base;
to form the frame using the remaining extract from the reinforcement that has already been driven in (for this, parts from 300 to 400 mm long are specially left;
after making the frame, pour the base tape with concrete;
wait for the concrete to dry completely.

In order to attach a foundation to the house, you will need a whole list of equipment. First of all, we are talking about the following tools: a shovel, a building level, reinforcing bars, sand, wood inserts, a mixture of concrete and boards for making formwork.

Foundation with expansion joint

An extension to a foundation house with an expansion joint is most often used in the field of industrial and multi-storey construction. That is, where the soils under the structure can differ significantly in their deformation properties. For example, quite often an extension of another number of storeys is connected to an existing house of one storey precisely by laying a foundation with an expansion joint.

In any case, the expansion joint must be provided for at the construction design stage.

At its core, any expansion joint, through which a foundation is connected to the house for another structure, is a heater in the gap between the basement ceilings and walls. Often, ordinary tow is used as this insulation. The place where the connection with the house is made is fenced off with a special decorative overlay, which is attached to the house wall.

In the conditions of building a house on heaving soil, experts recommend making the floor level of the extension lower than the floor level of the main structure. The magnitude of the difference should correspond to the expected deformations.

To attach the foundation to an existing house using an expansion joint, the following significant points should be considered:

Leave a small gap between the main house and the foundation of the extension (no more than 5 cm). In order to comply with the indicated requirement, before starting laying the foundation, boards pre-treated with waterproofing material should be attached to the foundation of the house. In the future, it is they who will perform the function of an expansion joint assigned to them.
In the conditions of one-story construction, the thickness of the expansion joint can be no more than 2 cm.
If desired, the expansion joint can be filled with any heat-insulating material. Most often, foam is used for this purpose, as well as foam. Outside, everything is closed with a decorative overlay.

If the main purpose of an extension to an existing house is to form a separate zone, and not to expand an existing room, a rigid connection of two bases between one house and another should not be done in any case, since the consequences can be the most undesirable. In this situation, it is much more advisable to use a deformation seam.

If we are talking about a small extension, it can be erected on a tape shallow foundation or foundation on piles.

Choosing the type of foundation for the extension

Experienced specialists strongly recommend that for the construction of an extension, use the type of foundation that was used for the construction of the main building. This is due to the fact that different bases react differently to contact with the soil and also react differently to the shrinkage of the building.

Accordingly, if the main house is built on a strip foundation, and the extension is built on columnar piles, sooner or later the auxiliary building will collapse. Thus, things such as connecting foundations should not be skimped under any circumstances.

If you plan to connect the building to the house, you can use various bases. Most often we are talking about the following options:

Strip foundation

For those who decide to use a strip foundation for an extension, you will need to complete the following list of works:

make markings in parallel with the tracing at the construction site of the base structure (this will require wooden pegs and an ordinary rope);
dig a trench along the marking;
fix the armature;
prepare a trench;
fill up a sand cushion (about 100-120 mm) and carefully compact the bottom of the trench;
lay a waterproofing film;
install a reinforcing structure;
fill the trench with a solution of cement and gravel.

The pouring of the strip foundation should be approached as responsibly as possible. It is better to do the work in several passes. As the first layer, one third of the trench is poured, and after drying, one second. The technology, in principle, allows the use of foam blocks, but not in all cases.

After complete drying of the cement-gravel layer, the formwork is built. The formwork is filled to the brim with concrete. After laying, the concrete is pierced simultaneously in several places. This prevents air bubbles from forming. After the concrete has completely dried, the formwork is removed.

And, finally, just before the walls are erected, the almost complete structure is covered with a layer of waterproofing material. Most often, roofing material, tar, liquid rubber or bituminous mastic are used for this purpose.

Column Foundation

If your plans include the construction of a small-sized and light-weight house, it is quite possible to use column foundation. It is usually made of either concrete or brick. For a medium-sized building, 6 supporting pillars are most often enough.

For the device of such a foundation you will need:

dig a hole (deep below the freezing level of the soil);
pour a sand cushion on the bottom;
install metal (or fiberglass) fittings;
to process the reinforcement with moisture-proof material (for metal reinforcing bars);
install formwork;
fill the base with concrete.

It will be possible to proceed with the construction immediately after the concrete has hardened. If it becomes necessary to increase the height of the pillars, a brick can be laid on top of the concrete.

Foundation on screw piles

The foundation on screw piles is the simplest and most budgetary type of foundation. It should be understood that it is only designed for structures that are not too heavy, since it cannot support a lot of weight. But if you are going to attach a wooden veranda to the house, this option is quite suitable.

This type of foundation in most cases does not require the participation of specialists. Even a person who has no experience in construction is quite capable of screwing screw piles with his own hands. Probably for this reason, many people opt for a foundation on screw piles.

If the foundation on piles is installed correctly, it can last for a long period of time.

But no matter what foundation you need to install, on screw piles, columnar or some other, the most important thing is that all work be done in accordance with the technology. Therefore, if you do not have enough construction experience, it would be most advisable to entrust the pouring of the base to experienced and qualified specialists.

I am making an extension to an existing house, how to solve the problem of an expansion joint and in general how to do it right?

At the junction of obviously uneven parts of the building (in this case, an extension of the porch), an expansion joint is needed. It can be laid not only with rigid mineral wool, but also with foam plastic, other elastic material

Various options for adjoining the extension foundation and its rigid connection with the existing one

The walls of both parts of the building must also be connected to each other.

Compromise option. There is a seam in the masonry filled with building sealant, but the walls are rigidly connected with steel brushes. This solution is suitable for the case when the main part of the building and the extension have the same type of stone walls and foundations.

If there is a possibility of significant shrinkage of the extension relative to the house, the best solution would be to install not three, but four walls, including the one adjacent to the existing one. The foundation and walls of the extension will have a closed contour, which will exclude horizontal deformations, in the second illustration this is option D.
The thickness of the expansion joint in our case is 10-25 mm, it can be filled with rigid mineral wool, foam plastic, foamed polyethylene.
The roof of the extension must also be completely separated from the old part of the building. The junction can be closed with an apron, fixing it on the wall.

The junction of the walls of the old and new parts of the house, located in the same plane, should be closed with an overlay (wooden board, metal plank), which should be fixed to the existing wall.

Expansion joint option for stone walls. The joint is laid with an elastic filler, in this case inside with a heater, outside with a special tubular elastic bundle. A steel plate, sealed on both sides, hides the joint and protects it from water penetration.

If you are attaching a three-walled wooden log house, the joint should be made with a straight key cut or on the casing: a bar (thorn) should be located on the existing wall, a groove is selected in the attached wall. The annex, losing moisture, will settle along the guide, which prevents the logs from torsion. Nails, staples are not used, the seam is filled with traditional insulation: moss, tow, jute. Outside, a board-overlay is installed.

If a log structure is attached to the house, the joint can be solved in accordance with the second option: a lock thorn-groove

Rigid connection technology for foundations

One of the main conditions is that the depth of the new foundation should be greater than the depth of the existing one. It is clear that different types of foundations perceive the movement of soils during heaving in different ways, so the foundation for the extension must be of the same type as the main one, regardless of the material and type of extension structures. The extension, as a rule, is made of materials that are lighter than those that make up the supporting structures of the main building - foam blocks, gas blocks, wood or wood concrete. But regardless of the type of extension material, the new foundation must have a greater depth than the existing one.

The docking joint must be at least 35 diameters of the reinforcement entering the body of the old foundation, plus double the length of the rod to enter the new foundation, this length is considered working. If the width of the existing foundation is not enough to comply with this rule for the working length of the joint, then the joint rods are installed in the body of the old foundation like anchors with wedging inserts, which ensures reliable fastening of the reinforcement inside the concrete.

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Thanks for the detailed information, Max. A detailed presentation of the technical side of the issue was very helpful for our experts to make recommendations for you. We hope our answer is helpful.

In order:

"How to make a joint for joining two foundations?"

Let's start with the foundation design. There are two constructive options for making an extension to the house:

Option 1

This video shows how to rigidly tie parts of the foundation of a building that are being built at different times with reinforcement.

Option 2

Please note: when erecting piles, try to ensure the largest possible area of their bearing on the ground, this minimizes the subsidence of the foundation of the extension. For drilling wells for piles, it is advisable to use a TISE drill, in many cities their rental is organized.

“Is it enough ... a U-shaped foundation, or do you need to fill in four walls?”

Probably, you meant the following: is it enough to build a foundation only along the outer contour of the extension, or does it need to be closed, the bay also has a grillage around the entire perimeter, including near the existing part of the building? If we guessed the essence of the question, we answer: enough, not necessary. The foundation serves to support the load-bearing walls, only under them it makes sense to build it. Your drawing shows a new pile-grillage foundation and, along the existing one, either a monolithic or prefabricated reinforced concrete slab rests on it. But two hollow-core slabs with a length of 5380 mm can be perfectly supported on two short extension walls. And for a monolithic floor, make one or two intermediate pile supports instead of a full-fledged grillage.

Please note: the piles closest to the existing part of the building supporting the grillage should be located as close as possible to the old foundation. The distance is the minimum that the TISE drill will allow, taking into account its expansion under the support platform.

“How to make a high-quality wall joint?”

“So, you need to make two separate floor screeds in the old and new parts of the living room?”

"What other moments might come up?"

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Expansion joint technology

2 . For an extension, the material of which is foam blocks, you can use a strip foundation. According to the construction technology, the level of the foundation (the sole of the foundation) must be below the soil freezing limit. If the land plot is characterized by very unstable (heaving) soil, perform the foundation of the extension just below the foundation of the house to avoid deformation during shrinkage. Strip foundation, extension walls are performed according to the technologies described by us in previous articles.

4 . All visible cracks are additionally filled with mounting foam.

6 . To protect against moisture ingress from the outside, the expansion joint is closed with special flashings, which are attached to the walls of the house and extension.

7 . Particular attention is paid to waterproofing. Water, snow from the roof of the house will fall on the extension. Therefore, its roof should have a sufficiently sloping shape so that moisture does not accumulate.

8 . In places where the building adjoins the house, galvanized corners are installed under the roof to protect against possible leaks.

9 . The exterior decoration of the extension, as a rule, is identical to the design of the old house.

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Connection Requirements

It is necessary to determine how to connect the new foundation of the extension with a residential building at the design stage, taking into account already existing factors. These include the following conditions:

type and design indicators of the foundation of the existing building;
characteristics of underlying soils;
the time elapsed since the previous construction (the main shrinkage occurs in 1 - 2 years);
commensurability of the weight load of 2 structures to be combined.

In any case, the help of experienced professionals is not superfluous, since mistakes can cost a lot later.

The result of linking the base and attached building structures with different shrinkage values of the bases is shown in this video

The construction of a new building begins depending on the season. In the spring, it is not recommended to start laying next to the already standing foundations, since at this time of the year the soils are in the most loose and watered state. The settlement value of a new extension on heaving soil may be much greater than the calculated value in the project, and be uneven around the perimeter. At the same time, there is a risk of movement of the undermined old support due to the high level of groundwater in combination with possible precipitation (rain or snow).

Before starting work, it must be taken into account that any new foundation (MZLF, piles, poles, slab) will definitely settle, even if it is made identical to the existing support.

Shrinkage

In construction, there are established settlement standards for various structures, the foundations of which are designed and manufactured in accordance with the current state standards.

You can find out the standard and make a forecast for the design of your individual house according to the data from the reference tables:

When comparing the calculated indicators, a new support unit is attached to the foundation of the old building at a given depth, taking into account its own settlement after a certain time.

The upper marks of the monolithic strip foundations of the combined buildings are carried out according to the calculation, and not according to the level, as in this photo.

It is the possibility of displacement relative to each other that determines which connection of the two foundations can be made. The following types of connections are used:

Rigid bond (reinforced concrete).
Separate installation (device of an expansion joint, taking into account the mutual influence of the supports).

The start of independent construction of a new module of an extension to a residential building is permissible if the following requirements are met: issue permits for the installation of a new structure, maintain distances not closer than the minimum allowable to nearby buildings and communications, ensure an independent draft of all structures in relation to each other.

Combining Foundations

In practice, this method is used for low-rise buildings, provided that the extension being built is functionally connected by one roof to the building already in operation.

Another condition for combining is the same type of foundation. If a residential building has a strip base that is not wide enough, then it is necessary to strengthen it.

The rigid type of connection is chosen for cases when the task is considered, how to connect the old well-established foundation with the new structure, for buried strip foundations. The extension is also designed as a monolithic reinforced concrete structure.

Strip foundations

Expose the existing tape to its full depth. It is necessary to dig a trench in parts (1.5 m - 2 m), not along the entire length at the same time, since the bare part loses its lateral support, which can lead to its deformation. The old building can be further strengthened with inclined supports.
Drill holes on the side of the connection, corresponding in size to the Ø of the reinforcement. In the middle of the tape, holes are drilled in a checkerboard pattern with a depth of about 0.75 of the width of the foundation itself, in the corners - 0.5 m. Reinforcement is driven into the middle holes, in which longitudinal slots are made with an inserted wedging insert for strong fastening in the hole. Reinforcement Ø 14 mm, having a periodic profile, is hammered into the corner holes. The release of bars should be at least 0.3 - 0.4 m.
The frame of the new foundation is knitted with its welding to the released reinforcement.
Filled with concrete.

If there is access to the subfloor for carrying out work, the holes for the tightening elements of the stud type can be made through with the fixation of the rods with flat plates.

Each option for a rigid connection of foundations has its own characteristics for specific cases, which it is advisable to entrust to professionals to consider and calculate.

Plates

A bunch of monolithic bases is performed according to the following scheme:

The slab of the old house, which has already precipitated, in this case not only becomes one with the new fill, but also receives additional reinforcement along the vertical connection of cement mortars due to the addition of 0.2 m - 0.3 m under it.

Separate supports

The distribution of the weight of the ceilings and walls of the extension should occur on its own support area, without creating tearing forces for the main foundation of the building.

The expansion joint, depending on the operating conditions, can be:

sedimentary;
temperature;
seismic.

The sedimentary variant (in the absence of other significant influences) has a width of 1–2 cm. Under the conditions of the mutual influence of the supports, binding to the bearing wall of the old house can be carried out with a deformation gap reaching 0.2–0.4 m, filled with an elastic waterproof material.

Frame wooden extensions are successfully operated on a pile foundation with a metal grillage, as in this photo.

Light verandas or summer kitchens can be attached on screw piles, even if there are already several adjacent buildings around. This is especially convenient if the site is located on a slope, slope, or with an uneven occurrence of solid supporting rocks.

At the design stage, they provide for the external design of expansion joints that visually separate the facade, in an open or hidden form, for example, hiding a gap with a subvertical downpipe. On the front side, they are usually covered with strips of a special flashing, sealed with a decorative material of low strength, which will not prevent the outer walls of buildings from moving relative to each other in the event of a possible uneven settlement. Under the roofing, the gaps are closed with the help of a compensating device.

An extension to the house, installed on separate supports, is a much less laborious process than a rigid tie, requires significantly less time and financial costs, and is also available for do-it-yourself work without ordering special equipment

The court did not reduce the penalty

Sales budget and sales cash flow schedule

How to make a expansion joint extension. Types of foundation for an extension to the house. How to determine the width of the sole of the tape base