Do I need to make a sand pillow under foundation: freedom from cracks or money down the drain

I remember, was still at school, parents were given another plot of land. We are interested to help, then climb on the neighboring areas. Each building as best he could. However, in the pit (or trench) before the laying of foundation all as one layer of poured sand. I was convinced that this should be mandatory. Only in the construction faculty explained that people "buried money" into the ground.

Sand makes a stronger base

If the precast foundation (concrete blocks or slabs), under it makes an ideal flat surface. Each of dense soil unevenness in dot concentrates load on the unit. Slightly smaller the load-bearing capacity, and worst of all - eventually appear irregular rainfall and, as a consequence, the bank.

Align the base of "zero" shovel virtually impossible. That is why, before laying the blocks on the surface of small thickness poured sand bed. It aligns the ground, and after loading the foundation distributes the load over the entire area. If the foundation soil durable drawdown excluded.

Sand bed - a waste of money

When in a private house it comes to the monolith, no special requirements to equalize the base there. Concrete numb to all the bumps and completely copies soil relief. Filling with sand on the ground nepuchinistyh complicates the work and increases the cost of them. We have to bring sand to fill it into the trench and tamp. While all of this can be and do.

Sand bed under the monolith to make weak and heaving soils. However, the "cure" this method can not be called.

Pour a layer of sand - made it worse

During digging trenches in the working marks can be found weak (peat, vegetable layer) or distending (clay loam) soil. How to properly manage them - a topic for another conversation. The most common way to solve the problem - to dig up a bad ground, and instead fill sand.

When the weak layer to a depth of 30-40 cm, its replacement sand - normal solution (sand bed is required ramming). If you want to go deeper, remember - well-compacted layer high in practice does not work. Even if you do it in layers. Over time, this pillow can prosest. So, we tried our best and made it worse.

Deeply immersed in the frost heave under Article do not undertake. I can only say that without water puchit not even clay. Often easier to solve the problem of water drainage than to complicate the construction of the foundation.

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