How to put the first row of timber on the foundation. The main nodes and connections of the frame house How to fix the strapping beam to the foundation

Modern designs of columnar and pile foundations have a very simple installation process and low cost compared to other types of foundations. In this regard, the popularity of such designs is increasing every year. Even an unprepared person can cope with the installation of a pile foundation, but, as in any construction, there is a nuance here. Most often, when erecting foundations of this type, tying a columnar foundation causes some difficulties.

Foundation for a wooden house

During the construction of wooden buildings, columnar and pile foundations are chosen. These types of bases have the following advantages:

withstand heavy loads (from 5 to 12 tons);
the pressure is distributed evenly to all points of support of the structure (this reduces the load on the ground);
increase the service life of the wooden parts of the building due to the natural air exchange of the foundation.

However, in order for the base to fulfill all its tasks, it is necessary to competently carry out all stages of work, and especially the lower trim.

Strapping technology

The design of the pile and column foundation consists of several constituent elements, between which there is a certain distance. Tying a columnar foundation with a beam unites the fractional parts of the foundation and makes them a single, functional element. If you neglect or make mistakes in this stage of work, there may be a violation of the integrity of the walls and roof of the building.

The beam system connecting the support points of the foundation is called the strapping (grillage). The main role of the strapping is to distribute the pressure of the building structure over all pillars or piles. Also, the grillage is a guarantee of the geometric correctness of the future log house and the roof of the building.

wooden strapping

Traditionally, wooden buildings are placed on a wooden grillage made of timber. Selected raw materials are selected for this task.

Important! When purchasing a beam for a grillage, you should inquire about the drying and processing of the material.

Due to constant contact with fumes and moisture, the grillage can infect fungus and putrefaction. To increase the strength of the structure during the construction of the strapping, even from very high-quality raw materials, special attention is paid to waterproofing. These works can be done independently.

The best material for grillage is raw materials from coniferous trees. Unlike other materials, it has certain advantages:

low cost;
long service life;
increased resinousness of rocks reduces the effect of moisture on wood;
increased strength.

Note! When buying material for grillage, you must independently inspect the timber. Raw materials with rot, knots and large cracks are not suitable for such work.

Wood for strapping must be carefully prepared. After buying a timber, it is necessary to treat it with antiseptics, this reduces the risk of destruction of the material from beetles and putrefaction. To protect wood from fire, I treat it with flame retardants, especially resinous species that are most susceptible to ignition.

The most durable type of wood for grillage is glued beams. In the production of this raw material, long drying is carried out. In addition, due to machine bonding under pressure, each beam has a clear shape, which reduces the risk of errors during construction.

Types of grillage assembly

When the material for strapping is selected, it is worth deciding on the type of fastening of the structure to poles or piles. Which method of fastening to use for the grillage depends on the material of the posts and strapping beams.

Clamps

The technology is considered universal - it is used to fasten a grillage made of wood and metal. The method fully performs its functions on fastening piles of any diameter. The technology is used only in cases where the design does not have an inverted U-shape. For connection, oblong rectangular bars are used. They are attached to the piles by welding or self-tapping screws (depending on the material). To level the bar, use a level. After fastening all the bars, beams are attached to them with the letter "P". Due to the bars, a strong fastening is created.

Thread

If the thread is not made correctly, there is a high risk of cracking of the constituent elements. However, other properties of such fasteners are very high. Each element of the foundation is wrapped with roofing material and treated with drying oil (this reduces pressure and protects the material from decay). After that, a beam is laid on two distant pillars and fastened to self-tapping screws. The fixed beams are carefully punched to the desired depth with a hammer. Most often, the threaded fastening method is combined with clamping to increase the stability of the structure.

Welding

The best way to connect a metal structure. Other types of fasteners are not able to withstand the pressure of a metal structure. For work, electric or gas welding is used. First, a metal beam is laid on two points of support and welded to the piles, then the other two beams are attached to the sides, so that a U-shaped structure is obtained. After that, the remaining elements are sequentially fixed.

When installing a wooden frame on a strip reinforced concrete foundation, a grillage is also used. The strapping here plays the role of fastening the timber and the concrete base. In this case, fasteners are embedded studs or.

When performing work, many face problems that are not discussed in any article. Before you start working on the grillage, you should familiarize yourself with the following tips from professionals:

The width of the strapping beam should be 2 times wider than the diameter of the pile or pole, this must be checked before purchasing materials. Otherwise, parts of the foundation are subject to cracking, and this will lead to the destruction of the grillage and subsidence of the log house.
To prevent foundation drops during construction, it is necessary to check the height of the pillars and piles. All components of the foundation must have the same size, otherwise the walls of the building will have large differences in height.
In order for the pressure of the grillage to be applied evenly to all piles or pillars, the fasteners are placed strictly in the center. This technique also increases the service life of both beams and parts of the foundation.

In the video below, you will see the detailed strapping technology. Also, you will learn various tricks that allow not only to increase the strength of the structure, but also to reduce construction costs.

Building a frame house is like assembling a constructor. The wooden frame house is assembled in accordance with the scheme. At the same time, the strength and reliability of the future structure depends on the quality of the assembly units. What are the features of the implementation of the main components and connections of the frame house? And how to properly fix the lower and upper harnesses, racks, jibs, crossbars?

Knots for connecting the lower trim

The lower one is a frame made of a wooden beam or several boards knocked together, which is laid on top. On the concrete foundation under the lower strapping, the so-called beds - boards are placed. They perform the main function - they level the foundation and hide those flaws that could be made during its pouring.

The beds are attached to the concrete foundation with anchors. Mounting points are located at a distance of no more than 0.5 mm. At the same time, at least the ends of the beams are fixed with anchors.

Connecting the bed to the concrete foundation.

To install anchors, holes of a certain depth are drilled. They pass through the board and go deep into the thickness of the concrete foundation. The depth of drilling and driving in the anchor is determined by the height of the wall of the house and the design of the foundation. For a traditional 2.5-3 m frame wall on a concrete base, the depth of the anchor to be lowered into the concrete is 15-20 cm.

The second option for mounting anchors is to concrete the anchor studs in the process of pouring the foundation. When casting a concrete slab or tape, hollow cones with an internal thread are inserted into the thickness of the uncured concrete in specified places. After the concrete has hardened, the anchors are screwed into these elongated cone-shaped studs.

Features of the anchor connection

Holes in the beam are drilled 2-3 mm more than the diameter of the anchor stud.
Wide washers can be placed under the heads of the anchor bolts to increase the area of their contact with the wooden surface, and increase the strength of the fastening.

Anchor fastening of the lower strapping.

Before fixing, mandatory waterproofing is carried out - a roofing material is placed on the concrete or its surface is covered with a special waterproof composition, mastic. After installation, check the horizon. Deviations from the horizontal level are allowed in sizes not exceeding 0.5 ° per 3 m.

Lower strapping knot on a columnar foundation

The fastening of the structural units of the frame house described above is used on strip and slab foundations. For columnar bases, a different scheme is used:

For ease of fastening, the upper part of the column supports should have a flat horizontal head with holes.
Wooden beams are placed on top of the headband, which act as a grillage.
In the beams, recesses of the required depth are drilled. They are drilled under the holes in the headband.
Fix the beam with bolts or screws.

Strapping from a built-in board on a pile foundation.

On a note

It is necessary to fasten the beam to the foundation. Shallow belts and slabs are subject to significant movement during freezing. Reliable connection of the beds and the lower harness ensures the reliability and durability of the entire structure.

The design of the nodes of the frame house

Vertical frame racks are installed on top of the bottom trim and fastened with nails. Fastening with metal corners is used for T-shaped connection of beams without cutting. It's easier to do it. Fixation of beams with metal nails is used at the junction with partial cutting of the lower beam. This is a more difficult do-it-yourself connection.

A joint without cutting is used for corner frame supports. Butt joint with fixation with plates or corners is used in the main nodes of a frame house, if the construction is done by hand, without the involvement of professionals. If experienced builders work, then they use a connection with a partial tie-in. It prevents strong movements of the timber and frame boards during drying.

On a note

The size of the cutting for the vertical frame rack is 30-50% of the thickness of the lower trim beam.

The corner joint without cutting is fixed with metal plates using wood screws. In this case, reinforced steel corners with several perforations are used. As well as durable self-tapping screws in light golden and silver colors.

Strengthening the corners for fixing the corners of the house is carried out due to technological processing - metal plates are hardened during the manufacturing process. Or due to the use of metal with a large section thickness, up to 2-3 mm.

Ways of fastening racks.

A punched connection is often used to attach posts in the middle of a wall. The supports are inserted into the prepared recesses and additionally fixed with nails. After that, their fixation in a vertical position is supplemented with jibs - diagonally inclined strips that abut on one side against a vertical rack, on the other - on a horizontal harness. For the convenience of the stop, the ends of the jibs are beveled - they cut off part of the end.

Temporary jibs

In the process of assembling the frame, temporary braces are also installed, which fix several vertical posts. Temporary jibs are placed between the upper and lower trim at an angle. They connect several vertical racks and are fixed with nails.

Temporary jibs are located on the outside of the frame. For their fastening, it is not necessary to cut down, but they need to be fixed in such a way that, upon completion of construction, temporary auxiliary beams can be easily dismantled. Therefore, nails are used to fix them.

Temporary jibs for racks.

Temporary braces hold the posts upright until permanent braces are installed at the bottom and top of each stanchion. Once the permanent braces are in place, the temporary fixing beams can be removed.

On a note

The construction project contains a description of the nodes of a frame wooden house in the drawings. He often does not describe in detail the method of fastening temporary jibs, since they do not carry the main load and support the frame temporarily.

Upper binding knots

The upper trim of the frame house is laid on the vertical frame supports after the installation of the corner posts. If the perimeter of the house is large enough (more than 6 m), then in addition to the corner posts, intermediate ones are also placed - in the middle of the wall. And only after - put the top harness.

After laying the top row, temporary braces are attached - through the entire wall. Next - attach the remaining vertical racks and struts to them. After that, the temporary braces between the upper and lower trim are removed.

It is most convenient to assemble the walls of a frame house in a prone position, knocking together the lower trim, vertical posts, crossbar, jibs and upper trim. And only after that raise the walls to a vertical position, where it remains only to fasten all the walls of the house together. For a strong connection of the walls of the frame house, a second upper trim is used, which overlaps the first upper trim.

Double top knots.

When using a double top trim, you can do without the use of steel corners. In this case, there is no need to partially cut off the ends of the boards, performing the connection "in the paw". Because such connections with cutting out part of the butt end violate the integrity of the board and, accordingly, weaken it.

On top of the second upper strapping, floor beams are laid. The beams are laid on the end, the distance between the beams is set depending on the size of the spans and fastened with nails.

wall corner

The corner of the frame house is the place of maximum heat loss. As a rule, it is in the corners that condensation accumulates and it is they that need to be insulated in the first place. Therefore, even at the frame assembly stage, care must be taken to ensure that the corners of the future frame house are warm. How to do it?

Smooth fixing plates are placed on the outside of the vertical beam. They connect adjacent single-level surfaces of a vertical post and horizontal beams. Fixing corners are located on the side. They connect mutually perpendicular surfaces. What else is important to know about angles?

During construction in regions with a cold climate, not a solid wooden beam is used as vertical racks, but a corner rack is assembled from separate boards. The resulting design resembles a well. A heater is installed in this internal space, which retains heat and limits possible heat loss.

Installation of corners in the frame of the house.

It should also be warm, for this, single racks are used, but the load from window and door openings is removed using a crossbar. The crossbar is fixed along the entire length of the frame wall with the help of a gash into all vertical posts. At the same time, it is important to take into account that under each window opening there should be at least 1-2 vertical support boards.

Rafter system nodes

The nodes of the truss system include all connections between its elements, namely:

Fastening the floor beams to the top trim.
Fastening the rafter to the upper harness.
Fastening racks on the gables to the upper trim and to the extreme rafters.
Fastening of internal racks to the rafter bed and to the ridge.
Fastening struts - inclined beams that support the rafters and rest on the bed.
Fastening the crossbar to inclined rafters.
Lathing fastening.

The nodes of the truss system.

The fastenings listed above can be done using corners or using nails if the elements of the truss system are connected with overlapping each other.

Fasteners

The following elements are used as fasteners for the nodes of a frame wooden house:

Mounting plates (corners or even plates with or without holes). Plates and corners are attached to beams or supports using wood screws.
Staples (straight and angled) - wire fasteners of a certain diameter. Their edges are bent and inserted into the ends or side surfaces of the beams.
Bolts - used to tighten adjacent beams and rafters, inserted into through holes and fixed in them with nuts.
Nails.

All connecting fixing and fastening elements for frame structures are made of metal. For fastening the load-bearing elements, reinforced corners made of hardened steel or increased thickness, 3-4 mm, are used. For fastening the supporting elements, corners made of ordinary steel with a thickness of 2-3 mm are used.

Variety of fasteners.

In order to protect against corrosion for the manufacture of corners, plates, galvanized steel is used. Rust protection is especially important in outdoor construction, when metal fasteners in the walls can become the center of moisture condensation, wetting a section of the wall. Therefore, galvanized fasteners are in high demand in various nodes of the frame house.

Node connection errors

The drawing of knots assumes the presence of sketches and descriptions. However, despite this, novice builders often make offensive mistakes. Let's list the main and most frequently repeated erroneous actions that beginner individual builders make when assembling a frame:

Not all jibs are installed. This is not true. The braces ensure the stability of the wall against wind loads. In addition to the jibs, to withstand the wind, it is necessary to use rigid plates in the outer skin.

Use a solid beam or boards tightly placed next to each other as corner posts. Such a corner will be cold. Moisture will condense in it and mold will develop.
Use "black" self-tapping screws for fasteners. They are not strong enough, especially if insufficiently dry wood is purchased for construction. When drying and warping, “black” self-tapping screws can be corny “torn off”. A more durable option is golden and silver-colored self-tapping screws, coated with galvanizing or a layer of chromating, phosphating.
An insufficiently dry tree is used, which shrinks heavily and “tears” the existing knots and connections.
And another mistake is not to use nails. These proven fasteners are often stronger than any self-tapping screws.

Frame construction is a new technology in which, despite its apparent simplicity, there are many nuances and features.

Question #47: I am building a country house. Tell me how you can fix (connect) the first row of timber with a columnar foundation (Sergey

Answer:Pillar foundations are usually used for the construction of buildings on soft soils and the construction of objects with heavy walls. Although wooden walls are not such, such a ventilated foundation is the most optimal for protecting the lower rims of the structure from rotting.

The service life of a columnar foundation ranges from 30 to 50 years, depending on the material used for the manufacture of columns: it can be metal or asbestos-cement pipes filled with reinforced concrete or just ordinary brickwork.

With such a foundation, you need to carefully calculate the weight of your house and determine the area of \u200b\u200bthe foundation supports, only after that you can choose the correct distance between the pillars and their number.

The most important moment in the construction of a house from a bar is laying the first crown and tying the first row of bars. All columns along the perimeter of the foundation must have a perfectly aligned horizontal surface and not by eye, but with the help of a level. The further state of the assembled structure of your house and the correct and uniform shrinkage of the whole house will depend on this.

The beam for tying the first row of the house should be 50 mm larger than the rest of the wall beams, for example, we take wall beams 150x150 mm and for the first row we take a square beam 200x200 mm. This is due to the fact that the entire weight of the structure of your house, along with the roof and snow, falls on the first row.

Now on the issue of attaching the first row of bars to the foundation posts. For the most part, when building wooden houses on columnar foundations, the lower crown is never fixed to the foundation, since the pressure of the entire weight of the house on the foundation provides it with the necessary stability. And the main positive thing in this case is that, if necessary, you can very easily replace a rotten crown without dismantling the whole house.

Of course, if your house is located in an area of possible flooding or there are stormy weather conditions in your region and at the same time your house can either float away or it can be “blown away” by the wind from the foundation, then God himself ordered to fix it to the foundation.

Everything here will depend on the type of columns of your foundation, if it is made of pipes filled with concrete, then it was possible to pre-concrete mortgages in them from studs with a diameter of 14 mm and already install and fix the first row of beams on them with nuts.

If you have ordinary brick posts, it was possible to install the same mortgages from a threaded stud in them, and if the posts are already ready and the question arose after their manufacture, then anchor bolts will help you. But in any case, you need to remember that moisture will condense at the point of contact between metal and wood and the wood will begin to rot from these fasteners.

So choose what suits you based on your local living conditions.

The reliability of buildings and their long service life depends on the correct arrangement of structural elements, their location relative to each other and on mutual work under load. The underground and ground parts of the house must constitute an integral system that functions in concert. Otherwise, the building will be destroyed, if not immediately, then over time. The tying of the foundation will help to combine disparate pillars or piles. It will prevent their vertical displacement, evenly distribute the load on the ground and eliminate the appearance of subsidence and deformation as much as possible.

Requirements for tying a frame house

For pile and column foundations, piping is required. Massive houses are installed on a tape reinforced concrete grillage, and during the construction of a light frame house, the strapping is done:

timber or log;
a package of knocked down or glued boards installed on edge;
metal profile.

Many believe that the lower piping of the frame structure with metal I-beams, channels and profile pipes will be more reliable than combining the foundation pillars with a beam, which is not entirely true. The fact is that strong steel beams, having a large length and cross-sectional dimensions, have a high cost. The best option for using profiles that are more suitable in price and dimensions is a small step between piles or pillars, which leads to additional costs for the construction of the foundation.

The disadvantage of using long metal products as a strapping of a frame house is the presence of residual deformation and the possibility of sagging of the beam under load or its own weight. Residual deformation affects the fact that the curved steel profile, after removing the load, cannot independently return to its original shape, which cannot be said about an elastic wooden beam. In addition, wood products are much cheaper than metal counterparts.

For a frame house, beams or a package of boards are most often used, and logs are intended for log cabins.

Lower foundation strapping bar requires:

the use of high-quality lumber - without knots and rot, with accurate dimensions and an acceptable moisture indicator;
performing reliable fastening of elements in docking nodes;
wood treatment with antiseptic and fire retardant compounds;
waterproofing devices between the foundation pillar and the horizontally laid timber.

Coniferous wood species are considered the best materials for strapping beams, among which pine and larch are the most popular. Other species are less suitable for use for various reasons. For example, there are many knots in the trunks of spruce, and cedar does not grow in all regions of the country.

Fastening a package of boards directly on the construction site is carried out using nails or screws. They are hammered or twisted to different depths in a checkerboard pattern.

Wood is treated with antiseptics in order to prevent the processes of decay and the development of fungus. As flame retardants, fire retardant is used, which protects the material from fire. We should not forget that the combustible resins that make up the pine are too dangerous.

Laying and fastening the strapping of the frame house

The technology of mounting the strapping beam includes several stages. First of all, the level of all pillars or piles is checked. If necessary, the supports are increased or cut. The lower trim should be placed on a waterproofing layer, therefore, a double layer of roofing material, hydroisol or other roll material is laid on top of the columnar foundation. For better fixation, the canvases are coated with bituminous mastic.

The fastening of the timber to the pillars depends on the capabilities of the material from which the foundation is made.

Either anchors or wooden plugs are installed in the thickness of the supports of the underground structure at the points of their docking with the strapping. This is done before the waterproofing device.

At the next stage, they begin to prepare materials intended for the lower strapping of the frame house. It is important to remember that the wood should not be wet, which you should pay attention to when buying a bar. If it is purchased in advance, then a closed and ventilated room should be chosen for storing the material. Products should not be dried in the sun, as direct rays can contribute to their deformation and cracking.

There are two main ways to connect adjacent bars:

in half a tree - in the joined elements, even recesses with a thickness equal to half the thickness of the timber are mirrored;
in a half-paw - cutouts are made at an angle so that no voids form when connecting the strapping parts.

After the preparation of the beams and the waterproofing device, the stage of laying the strapping into the design position begins. First of all, proceed to the design of the corners. To do this, nails mark their location. Do this sequentially, starting from one of the outer corners. After that, using a string stretched between the nails and a construction square, they check the correctness of maintaining the corners. Most of them should be extremely straight, but with a complex shape of the house in plan, they can have dimensions other than 90 degrees. These parameters are indicated in the design drawings.

After adjusting the centers of the outer and inner corners of the strapping of the frame house, they proceed to the direct laying of the timber. Work also begins to be carried out from one of the corners, focusing on the established markup, but the rigid fastening of the nodes is not performed immediately. This makes it possible to correct the position of the parties as needed, which is very important.

At the junction of wooden beams, a jute tape is laid, which acts as a soft pad. It will save the elements from friction, and the hearing of the household from creaking.

At the end of the installation, the horizontal framing of the frame house and the correctness of the angles are finally checked. After that, its parts are rigidly attached to the foundation pillars and to each other, and the bars are additionally fixed to each other with rigid corners or metal brackets. The beams are fastened to the foundation in several ways:

anchors embedded in the poles. At the fitting stage, bolt holes are drilled in the bars;
nails (or screws) driven (or screwed) into wooden plugs installed in the body of the foundation;
wedge bolts, providing the most reliable fastening.

Finally, it is worth recalling that all joints of the lower trim of the frame house must have a support under them. If it is necessary to build a beam between the pillars, a rigid and reliable fastening of the assembly will be required. In addition, one should take into account the inadmissibility of loading a composite beam in the absence of a support under the joint.

Often, a double row of bars is used to reinforce the strapping of a frame house. In this case, when cutting under the logs in one of them, the second one remains solid, which means it is more durable.

By the type of soil, if you have read this publication, you already know that a reliable foundation for the entire building directly depends on the soils at the construction site.

In cases of soft soils, a rigid monolithic frame will be a good choice, in dry, non-heaving soils, a shallow foundation can be made, and in some cases, a foundation made of asbestos pipes or brick columns may be the best choice.

But, no matter what type of foundation you choose, you will have to start the construction of frame walls by laying the lower trim, which directly rests on the foundation of the building. As a rule, the strapping is made of thick and wide boards or timber, which are attached to the foundation.

This is where the question arises for many - but how, in fact, to properly lay the timber on the foundation and securely fix it?

Let's see what options exist and how to do the installation correctly so that the erected walls serve faithfully for many years.

How to lay the bottom beam on the foundation?

So that the wood of the lower beam, which is in direct contact with the foundation, does not undergo decay processes, the beam must be thoroughly treated with a special antiseptic composition.

To isolate the beam from contact with the foundation material, as a rule, a layer of waterproofing material is used - roofing felt or coating insulation based on bitumen.

Do I need to fasten the beam to the foundation?

This question can be answered unequivocally - it is necessary to fix it, since the durability of the entire building depends on it.

The foundation is constantly experiencing impacts leading to a change in its geometric parameters. This is especially true for shallow foundations of low-rise buildings.

The forces of frost heaving, the impact of groundwater, the swelling and drying of the soil - all this leads to movement. If the beam is not fixed, then the building, in the event of an unfavorable development of events, may simply move off the foundation, deform or collapse.

Therefore, the beam must be securely fixed to the base.

Fastening the timber with anchor bolts

The beam to the foundation base can be attached in different ways. One way is to use anchor bolts. Its advantages are that such fastening can be performed directly in place after laying the timber.

To perform such fastening, the beam is laid on the foundation through a layer of waterproofing, after which holes are made in those places where it is required to fix the beam.

To do this, using a drill and a crown, drill to the depth of the crown:

After that, the wood is removed from the hole with a chisel:

Next, using a drill, a hole is made to the foundation and then, using a perforator, the foundation is drilled to the depth required to install the anchor.

After that, the anchor is installed and with the help of a hammer it is deepened into the drilled hole:

Then, using a spanner wrench, the anchor bolt is tightened, securely fixing the timber at the junction with the foundation:

The fastening of the lower trim beam to the columnar foundation with grillage can be performed according to the scheme shown in the figure below:

If during construction the choice fell on the screw foundation that is popular today, then the fastening is carried out as follows - first, two beams are connected to each other using a notch in the paw or using these overlays, as shown in the photo below:

After that, the beam is screwed to the screw pile site using self-tapping screws:

You can watch the whole process of the device of the lower strapping of the pile-screw foundation using a beam in the video below:

As you can see, it is possible to securely fasten the lower trim of a log bath or a frame house to the foundation in different ways, each of which should not cause any particular difficulties in the construction of a building. If you are not confident in your abilities, contact a team of professionals with experience in performing similar work.