What is most important when building? Finally, every builder answers. You can’t do something right and something wrong. The house must be fully functional. But if you have to mark the really important immaculate things, it’s the roof and especially the foundations.
However, motherboards have undergone major changes in recent years. Entire systems have been created that insulate foundations from both cold and moisture.
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You can fix the problem in the roof. A hole in the insulation can be closed. But how do you repair the foundation if the house is sitting on it? They hold him together. Cracked foundations, drifts, not deep enough, not sufficiently insulated… These are the biggest problems that can arise.
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Concrete is mostly used to build foundations. The use of earth foundations, for example, for structurally small and light houses is marginal. Otherwise, in this case, concrete is taken as the foundation, regardless of whether we are talking about houses made of brick or wood. It is equally important not to forget the second component that makes structures stronger and more cohesive – steel reinforcements.
Which foundations are built is up to the planner, who is guided by the load on the house. For light wooden structures, foundation steel piles or foundation feet can be used. They are found primarily in the skeletons of wooden buildings. If the feet are too large for the calculated load, it is better to move on to the next solution. This involves the distribution of forces over a larger area, which is represented by foundation belts or plates. Here we enter the area that is probably the most widespread in our country.
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Which concrete should be used?
This question is very important and should be answered by an expert. After all, concrete science is so extensive that it takes several semesters even at the Faculty of Civil Engineering. In general, it can be said that for structurally undemanding buildings it is sufficient to use concrete of class C12/15 or better C16/20. As problems with static loads increase, the need for quality concrete also increases. Today it is no longer worthwhile to concrete foundations yourself. The quantity is so large (especially for foundation slabs) that it is much more advantageous to buy concrete from a concrete mixer. In addition, the quality and integrity of the concrete layer is guaranteed here, which cannot be guaranteed in small series.
Both variants have been popular in the Czech Republic for many decades or even centuries (passports), and our builder is not keen to get rid of them. Beams are actually load-bearing walls that are sunk at least to a frost-free depth and then support the weight of the surrounding walls or partitions and load-bearing columns.
With simple foundation belts, only houses with lower loads can be built; high loads require graduated foundation belts. For their construction, either concrete is poured into the formwork or special fittings are used. Foundation slabs are suitable where there is less stable ground, problems with the soil, groundwater, etc. exist. This is actually a large reinforced concrete slab on which the house is then built. The board then distributes the load over the entire surface.
Of course, other problems can arise here too, which is why the floor slabs are sometimes supplemented with piles, pillars, etc. However, the floor tiles have changed significantly in recent years.
Nowadays it is no longer enough to just build a concrete slab and remove the house and its insulation etc. on top of it. Entire systems have been created that insulate these foundations from both cold and moisture. The most well-known is probably the use of foam glass, which forms an insulating thermal layer with a thickness of up to 50 cm and at the same time has a drainage character. But only to a certain extent. This material cannot be used on impermeable surfaces. The second variant that is widely used today is the construction of foundations on hardened polystyrene. Massive system thermal insulation elements are laid out on the floor plan of the superstructure consisting of lost formwork blocks. Additional insulation in the floor of the house is no longer necessary, making the entire construction simpler and more cost-effective.
Also very interesting is the possibility of releasing subsoil compaction and creating a kind of concrete base plate that is connected to an air bubble above the subsoil. So it is a crawl space system (base rails on which the floor is laid so that a ventilated air space is created underneath), but with the fact that the floor is solid, solid and made of concrete. The free space under the base plate can serve as an air reservoir for recuperation or to supply air to the fireplace. Such a solution made from prefabricated components enables quick implementation: complete foundations of 100 m² can be built in just six days.
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When you build today, you need to isolate the foundation from the rest of the structure. The insulation is designed to prevent water and heat leaks. The support strips and panels must be protected on the sides by an insulating layer, which usually consists of asphalt screed or heated asphalt strips and thermal insulation in the form of hardened polystyrene. The latter has the fundamental advantage that it is non-absorbent and is given high strength by extrusion, so that accumulated dirt does not destroy it. It is stupid to concrete floor slabs with a mixer. For such large areas you need to order a mix.
Thorough compaction of all layers is extremely important. Foundation structures must also be insulated against water penetration in the horizontal direction. Rising capillary water must not affect the structure of the house itself. Water would lead to the deterioration of insulation, the creation of thermal bridges, the destruction of building materials, interior condensation and the formation of mold…
Watch out for outbuildings
Extensions are often a problem. For example, the owner thinks that the house should have a terrace and adds it to the existing house. Unfortunately, this is a major intervention in the structure and, if carried out improperly, the integrity of the foundations in terms of insulation and insulation will be disrupted. Therefore, everything must be done with extreme care. In particular, it is important to ensure that the subsoil is perfectly compacted, because the house that has been built has already “settled”, but the terrace or the extension has not.
There is a certain amount of mutual movement to be taken into account, which means that special expansion joints have to be created and the extension cannot be firmly connected to the house. An investor should consult an experienced planner for any expansion.