The main purpose of the blind area around the house is to protect the foundation from the effects of soil moisture and soil movement. The blind area is necessary! But many homeowners postpone its construction until later, are somewhat dismissive and make mistakes, which will be discussed on our site of advice.
Error firstth – too narrow blind area
With the length of the blind area around the house, be it soft or hard, everything is clear. It runs along the entire perimeter, the length of the blind area depends on the size of the building itself. But with width, homeowners often make the mistake of saving and making the foundation protection too narrow. In fact, the width of the blind area should be such that not a single drop of water from the roof falls on the open ground. That is, the width of the blind area should be at least 20 centimeters greater than the width of the roof overhang.
Important! There is, for example, MGSN 1.02–02 TSN 30–307–2002, which deals with the norms and rules of landscaping in Moscow. The document says that the width of the blind area should be from 80 to 120 centimeters. If the soil is with karsts, the geological conditions of the construction are complex, then the width of the blind area is increased to 150, and in some cases up to 300 centimeters.
Mistake the second – there is no slope or it is too small
In no case should water remain on the blind area! It is necessary to provide a transverse slope of at least 10% of the width of the blind area. That is, if the width of your blind area is one meter, then the height difference between the sides of the equipped formwork should be 10 centimeters, no less. Some make a mistake precisely when pouring concrete. It is necessary to control so that it does not flow and does not level out in the horizontal plane. Otherwise, the slope will be significantly less.
Important! Do not forget also about drain holes with grates for water, gutters. These trays will become part of the overall drainage system..
Error three – violation of concrete technology
It seems that everything is simple – cement, crushed stone of fraction up to 20 millimeters, sand and water. But many homeowners violate the proportions and technology of mixing the mortar, especially if they do everything by hand, without a concrete mixer. As a result, the blind area begins to collapse quickly, cracks appear on it.
So, to get 1 m3 of concrete solution M250, which is the most popular option in low-rise construction, you will need:
- Cement M400 – 330 kilograms;
- 750 kilograms of sand;
- 1050 kilograms of crushed stone;
- About 200 liters of water.
Important! First, all dry ingredients are thoroughly mixed. Only then gradually add water.
The portal provided instructions for pouring a concrete blind area, we advise you to re-read it to do everything right.
Error fourmouth – refuse to insulate the blind area or do it wrong
The insulated blind area helps to reduce the cost of heating the house in winter and to avoid frost heaving at low temperatures. Experts say that the additional cost of insulating the blind area pays off thanks to the advantages of this construction method.
Fifth mistake – do not make the correct base of the soft blind area
A soft blind area is made of gravel, lawn or light tiles, including metlakh. The main mistake in the construction of such a blind area is to forget about the correct waterproofing. In this case, the blind area will simply pass part of the water to the foundation. Experts advise using profiled membranes as one of the base layers of the soft blind area, as the best way to divert water away from the building.
A high-quality blind area will protect the foundation, adhere to time-tested technologies, use modern materials and avoid the mistakes we have described.