Properties of soil and their influence on the foundation

Before the beginning of construction works it is necessary to collect the information about characteristics of a ground of that place where house building will be carried out. If the official data is absent, do all necessary checks without by yourself. To carry out this work it is necessary to dig a pit 2 meters deep and to define a condition of ground waters and frost depth for a ground.

If ground waters are deep enough (more than 2 m below the ground level) such ground is called dry. The sandy foundation is necessary for similar ground.

The sole of the foundation in dry soil should be established on depth 80-90 cm. Then it is necessary to fill a bottom of a trench with sand in several layers (each layer is 10-15 cm thick). Thus each layer should be watered. Then concrete is allocated in a timbering, and the top of the foundation should be established on a mark of 50 cm from earth level. Then the top of the foundation is accurately leveled by a sand-cement mixture. Waterproof the top of foundation with appropriate material.

If level of ground waters is considerably below the frost depth of a ground but less than 2 m deep than the foundation should be 1 m deep in sandy and loamy soils.

If the depth of frigidness of a ground coincides with level of ground waters in that case process of installation of the foundation will be more difficult and labor-consuming. At such a case the foundation laying should be de below the frigidness depth 40 cm. For reduction of expenses and materials a sandy pillow may be applied.

The bases on a sandy pillow, as a rule, are used under following circumstances:

— For replacement of soil in the basis;

— For economy of building materials;

— For lifting of the floor level over the level of ground waters.

Before their installation it is necessary to fill a hole with coarse-grained sand in a layer of about 20 cm. After that sand pillow should be well watered and properly stamped. In the presence of strongly flooded ground it is necessary to make a drainage, otherwise there can be a silting of sandy pillows.

After timbering removal, by means of hot bitumen it is necessary to finish the foundation walls in order to avoid increase in coupling of walls during the winter period.

How to build a strip foundation

Spring is just around to come, my friends, and with it the construction season. If you want in this year to build a house, I advise you now to think about the first steps - the foundation. Of course, I have no doubt that you will definitely hire the architect for a project, builders. And leave for yourself the responsibility of monitoring and general management. But do not forget that a decent control can carry out only those who know something in construction technology. I hope I convinced you? Then let's deal.

Strip foundation is good because it allows you to build garage or cellar under your house, or maybe just a basement room for different economic needs. It’s good because it can withstand fairly heavy stone or brick walls and ceiling. Strip foundations can be divided into several types: sunken, shallow-buried. And depending on the technology, we can distinguish monolithic and precast foundation.

Buried foundation is needed in wet, freezing soil, as well as in those homes where you are planning to build basements. When calculating the width and depth of the foundation it’s necessary to consider two factors: the composition of the soil and the weight of bearing structures of a future home, that is, what load will be sent directly to the foundation. Here is an interesting thing. Somehow, most of the future homeowner believes that the smaller the load, the less attention you can give to your foundation. But it’s not true. The fact that the house built presses the foundation. As it presses it into the soil pressure on top gives it extra stability. But the foundation is affected not only by the vertical load of the weight of the walls. There are a load which spreads horizontally. It’s particularly strongly felt when the soil is freezing and thawing. If the pressure of the walls is insufficient then, the horizontal pressure can warp the foundation. And that trouble threatens us cracking and distortions of the walls and other "joys". The solution, in essence, is simple. If simplified, the sound will be as follows: under construction on heaving soils, the lower the weight of the whole construction of the house, the thicker must be the foundation. For stability you can do not the whole wall wider, but design the expansion of the inner side of the wall to the bottom.

By the way, about the soil. In fact, with proper approach, heaving soil does not pose a strong threat. Much worse, if the soil is heterogeneous - somewhere in the sand, somewhere in the clay, but somewhere sandy loam. Here, in this case there is a real danger that the "wrong" foundation will “distort” the house. Therefore, in such soils the foundation should be laid below the frost point not less than 20cm (or approximately 8 inches).

Buried foundations are erected in two ways. The first - by digging the foundation pit, then by putting a solid foundation or by putting blocks in the case of construction of precast foundations. Pit in this case increases the cost of the works, but gives the opportunity to build a basement. In the second method simply dig a trench in which the foundation is laid. Frankly, the second method, though allows saving on the earthworks, but I personally do not like it. Most of the building teams do as follows: knit reinforcement, put it in a trench and pour concrete. In this case, by definition, the foundation walls are rough, part of the moisture from the mixture soaks into the ground. This leads to a decrease in the strength of the foundation.

Technology of construction of shallow-buried basement is very simple. The land is marked. By the way, do not forget to check out the angles, they must be strictly straight. Among other types, I prefer solid foundation. Of course, it’s more time-consuming process, and the erection of formwork takes extra time, but the monolithic foundation fully justifies all expectations for reliability and durability. Dig a trench to a depth of about 50 cm (20 inches) - depending on the weight of future construction and composition of the soil. Bottom of the trench is filled with sand, periodically watered and thoroughly compacted. You can fill it by rubble, and then pour cement mortar. It will prevent a moisture of the monolith foundation from being leaked out in the sand. Then we’ll do the formwork, bringing it to 30cm above the ground surface. The height above ground will serve as a socle (pediment) for future home. Do not forget to immediately leave the holes for water and sewer pipes, otherwise they will be cut through the monolith foundation in the future broking the integrity of the monolith. During the construction thoroughly check the verticality of the walls. It is very important as it influences the durability of the foundation. The mixture should be poured gradually, in layers of 15cm. Each layer is rammed, don’t leave voids. You can and should tap the wall of formwork - again, to fill the entire volume of mixture evenly. After the erection of the monolith it is covered by the waterproofing materials. It will protect the walls of the house from capillary moisture. Builders generally use roofing felt, but I would advise you not to save on the little things and take a more modern materials. Roofing felt quickly becomes useless.

Shallow-buried foundations can be placed just under the rather mild low-rise buildings. If the soil heaving, the foundation can be strengthened as follows: after the construction of the basement just fill up the trench with clay, it will serve as a safety cushion. Also it’ll stop soil moisture. Remember that it must be thoroughly compacted. There’s another way. If you want to be sure of durability design, treat the soil adjacent to the base by polymer binding substances.

Must take care of the blind area. Otherwise at the very beginning of construction, water will seep under the foundation. Incidentally, the issue of water in the area is one of the most painful. I, unfortunately, often seen as ineptly designed location of the house itself and the drainage system on the sites - the house stands in a valley, the garden - a little higher, and all the water drains directly to the walls of the building. Or another option - there is no organized drainage water that flows during the rainy season from the roof. You can just say that soon the owners expect trouble. And if in a wooden house foundation and sagging walls can still somehow be repaired, the stone houses have no possibilities to perform deep repair. The walls are just cracked, and easier to rebuild a house than to repair. So, try to think several moves ahead, and you’ll succeed.