Frame houses are currently gaining in popularity. Walls constructed using this technology are distinguished by good thermal performance, low cost and ease of installation. The design and construction of any building must begin with the foundation. An excellent option would be a columnar foundation with your own hands for a frame house, but in the presence of special circumstances, it is worth considering other types.
Features of frame walls
If we consider the frame in terms of foundations, then this technology has several advantages:
- Light weight. The smaller the mass of the walls, the lower the load on the foundations. The foundation of a frame house will be less powerful and costly than, for example, for a brick one.
- Good deformation resistance. A building is better than a brick or block perceives small shifts of soil. Cracks do not appear on the walls.
What foundation to choose for a frame house
When choosing the type of foundation you need to consider several features:
- soil strength at the site;
- groundwater location level;
- number of storeys of the building;
- the need for a basement device.
To find out the characteristics of the soil, engineering and geological tests are carried out at large construction sites. In private construction, ordering an expensive procedure is not necessary. There are two ways to find out the type of soil and the location of groundwater:
- passage of pits;
- manual drilling.
It is necessary to develop the soil to a depth that is 50 cm higher than the estimated mark of bearing the foundation. The type of soil is usually determined by eye, after which, according to special tables, you can find out the strength characteristics. The characteristic features of each type of soil can be found in GOST “Soils. Classification".
It is necessary to check the characteristics before building the foundation for a frame house with your own hands. This will allow you to choose the type of foundation, its cross section and the depth of the foundation. The wrong choice of the support part is a big problem in the future.
Column foundation
An economical option is the columnar design. Performing such work yourself is quite simple. But the option has the following limitations:
- a low level of groundwater location is required (the distance from them to the base of the foundation should be at least 50 cm);
- Strong bearing soils are required (mainly pillars are used on good soils - coarse soils, refractory clays, loams and sandy loams);
- the impossibility of building a basement.
When building on heaving soils, it is necessary to lay the bottom of the pillars below the level of freezing of the soil or use bored piles.
The foundation can be made in two ways: from prefabricated elements, from monolithic reinforced concrete. In the first case, typical FBS blocks are used. When choosing this option, there is a need for lifting equipment, since the foundation details weigh hundreds of kilograms.
Monolithic reinforced concrete is a good option for private construction. To build your house in this way is possible without the use of lifting equipment. But you need to take care of the delivery of concrete with a mixer and the rental of a concrete pump. This minimum of technology will allow you to make the foundation for a frame house quickly and with minimal labor costs.
Before you begin construction, you need to perform the calculation of the column foundation. The initial data will be the characteristics of the soil and the load from the building. For the soil you will need to find out:
- the strength of the carrier layer (selected approximately depending on what type of soil is on the site);
- soil freezing depth (can be found on a special table for individual cities);
- groundwater location level.
The last two indicators affect the depth of the foundations of frame buildings. It is recommended to support the sole so that it is approximately 30 cm below the freezing mark and 50 cm above the groundwater level. If it is impossible to fulfill both of these conditions, use shallow supports. At the same time, great attention must be paid to waterproofing and insulation.
In the calculation, it is necessary to find the minimum area of the bottom of the column, its dimensions in plan. This is best done by a professional. But if necessary, you can find simplified formulas that allow you to perform rough calculations. To increase the bearing capacity and reduce material consumption, columns with a widened sole are used.
The construction of a columnar base for a frame house with your own hands begins with soil preparation. It is required to dig holes with a step of support. This takes into account the cross-section of the pillars and their length. The soil at the bottom of the pit is compacted, sanding medium or large fractions with a thickness of 15-50 cm is carried out.
The next step is to fill in the footing. Skinny concrete of classes B7.5 – B12.5 is used for these works. The thickness of the footing is 70-100 mm. Such preparation will allow to further level the base, provide waterproofing for the monolithic column during pouring and building strength. It is used in the construction of pillars using monolithic technology.
Next, formwork is installed. It can be made of wood. Recently, foam formwork has become popular. It is not removed after completion of the work and plays the role of insulation.
For vertical reinforcement, class A400 reinforcement with a diameter of 10-12 mm is used. The number of rods per section is selected depending on the load. To connect the rods to each other, use clamps made of reinforcement of class A240 with a diameter of 6 mm in increments of 50-100 cm. The fittings must be installed so that it does not extend beyond the concrete by about 20-30 mm. Such a protective layer will prevent damage due to corrosion (rust).
For pouring supports it is recommended to use concrete of classes B15-B20, depending on the strength of the soil and the mass of the building. One element of the foundation is poured at a time. This will avoid the appearance of seams, which become the weak point of the structure during operation.
After pouring, it is necessary to give the foundation time to set strength. On average, concrete gains full strength in 28 days. This condition is relevant at normal humidity and average daily air temperature of +20 degrees Celsius. The colder the slower the hardening of the material. Formwork can be removed after concrete reaches 70% (50% in exceptional cases) strength. After stripping, you need to take care of the waterproofing of the posts. This can be done using bitumen mastic or roll insulation (roofing material, linocrom, hydroisol, etc.).
Two columns of rolled waterproofing material are laid along the edge of the posts. After that, you can proceed with the installation of the lower trim of the frame house. For this, a beam is used, the cross section of which must be selected depending on the load and the pitch of the foundation columns. Read more about technology in the article about columnar foundations.
Strip foundation
What is the best foundation for a frame house, if necessary, to make a basement? Here you can give an unambiguous answer: tape. Only this option will allow you to make a basement or underground. This is not the cheapest foundation. The cost increases due to the high complexity and material consumption. Significantly increases the volume of earthworks.
As well as the previous version, the tape can be manufactured using monolithic and prefabricated technology. For the basement you will have to do a recessed tape. It is necessary to carefully check the location of groundwater and the lack of likelihood of flooding the basement.
The width of the strip foundation is chosen so that it is about 10 cm larger than the thickness of the walls. Overhang of the frame from the supporting part of the building is not allowed. In preliminary calculations, the required width of the sole of the tape is found.
It is also necessary to choose reinforcement. Its total diameter depends on the cross-sectional area of the foundation. As working fittings, rods of class A400 with a diameter of 10-14 mm are used. They are placed along the tape. To ensure joint operation of the reinforcement, it is also necessary to provide transverse horizontal and vertical reinforcement. It is made of reinforcement with a diameter of 6-10 mm.
For filling the tape, it is recommended to use concrete of classes B17.5-B20. Before starting work, prepare the base: compact the soil, make a sand bed 30-50 cm thick. Next, formwork is installed from wooden boards or expanded polystyrene.
When filling the tape, vertical seams are not allowed. If it is not possible to perform work in one step, concrete is poured in layers. At the same time, the weakened seam is horizontal. First fill in one area, and the next day - another is impossible. Read more about technology and subtleties in the article on shallow strip foundations.
Screw piles
If it is not possible to make columnar foundations for the frame house with your own hands due to the low strength of the soil or high humidity, use pile supports. The best option here would be metal screw elements. Their bearing capacity is enough for a frame house. Most often, piles with a diameter of 108 mm are chosen.
Pile pitch is determined by the calculation of the foundation.
The advantages of such a foundation for a frame house include:
- low cost;
- lack of earthwork;
- ease of installation;
- availability;
- the possibility of use on marshy soils without dewatering;
- the ability to use on weak soils.
To immerse screw piles using special equipment or hand tools. You can use a manual drill for these purposes.
The length of the pile is selected depending on what base is available on the site. Well, if the end of the element will be able to get to the ground with good strength.
After completing the installation of the supports, you can begin to manufacture the grillage. In the case of a frame house, it is made of wood and also serves as the lower wall trim.
There are several other types of foundations that can be used. For example, piles using TISE technology are perfect for heaving soils. And with a very high GW, you can consider the option of manufacturing a monolithic slab.