Blind Area For The Foundation

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

The durability of the building depends on the availability of a quality blind area. It is a mistake to think that the presence of a concrete strip around the house will save the foundation from moisture - this, unfortunately, is just a path for walking along the house. The article provides information for the zealous owner about creating the right blind area

The main task of the blind area

The decorativeness of the blind area, which everyone is puzzled with, is not the main factor. The main task of the structure is to drain water at a sufficient distance from the plane of the foundation walls and preserve the soil in a dry state. Today the blind area is a prerequisite for construction. If this element is missing or destroyed, then it must be created from scratch or restored.

Types of blind area

Depending on the natural conditions and the type of soil, the blind areas are made in different ways. There are three main design types, which are divided according to the properties of functionality: soft, hard. And also in terms of the complexity of technologies: two- and multi-layer; according to the structure of the material used: prefabricated, bulk, cast. Let's consider the most common options.

Rigid concrete blind area

This is the most durable, solid and durable option. It is used on solid ground or on a compacted sand and crushed stone pad. The technology provides for the mandatory removal of 30-40 cm of the soil layer. The width depends on the projection of the roof projection, usually 80 cm.

The excavated part should be treated with herbicides in order to exclude damage to the future blind area by the growth of weeds. On loose soil, to ensure moisture permeability, a layer of clay is laid out. On dense soil, a sand cushion (10-15 cm) is created and a layer of crushed stone is poured and compacted / rammed.

Further, the formwork is being built, with the installation of thermal seams with a step of 1, 5-2 meters, they will also serve as beacons when pouring. For thermal seams, you will need slats with an edge height that matches the thickness of the blind area, maybe a little more. Then, a mesh or an overlapping iron bar is reinforced.

Concrete / cement must be used of high quality with the addition of frost protection - a plasticizer. After pouring, you need to trowel and create a flat surface. Then the raw concrete should be periodically sprinkled with seeded cement and smoothed. The technique is called "iron", i.e. creation of a particularly durable top layer, which subsequently acquires a steel, dark blue tint.

Sandy blind area

An interesting way, giving out a visual similarity to the rocky surface of sandstone, is the sandy blind area. In terms of quality and stability, it is not inferior to concrete. Preparation is carried out in the same way. Sand is poured onto the compacted layer and liquid glass is poured into it in a warm form, followed by the application of a hardener. Several such layers are made, at the end of the pouring, the mass is covered with a film until it hardens completely (three days). In the form of hardeners, 10% calcium chloride or 3-7% sodium fluorosilicate are used.

The blind area is soft economical

It is created on the basis of waterproofing, without disturbing the natural balance, while maintaining the naturalness of the landscape, since grass is planted on top. Effectively removes water due to a moisture-proof membrane laid at an angle from the foundation.

In the prepared trench, a roll-up waterproofer is laid over the foundation. It is sprinkled with sand on top, then with soil and lawn grass seeds are planted. It is not necessary to tilt from above. It is not recommended to walk before subsidence of the soil and the formation of dense turf.

If we consider cold regions, then it is advisable to put protection against deformation during freezing under the waterproofing. To do this, you can use Penoplex or extruded polystyrene foam. When freezing more than half a meter, you need to take thicker sheets.

For waterproofing, you can not take a plastic film, roofing material. Also, bituminous materials are not suitable due to their fragility when freezing. It is recommended to take only a film with a PVC base, polypropylene materials.

Professional advice

Only a 3-meter width of the blind area can give a full guarantee of water drainage, therefore it is important to make gutters on the roof with a slope and drainage of storm water further from the foundation. Drainage trays and other ready-made elements mounted next to the blind area help a lot. Any elements can be installed: polymer concrete, plastic.

Such a combined design provides a complete outflow of storm water into the drainage system or removal of water at a sufficient distance from the house.