Waterproofing the Foundation

Step-by-step execution of foundation waterproofing can be described as follows:

• A 2–3 cm thick cement mortar is laid over the foundation. After it sets and dries, one layer of ruberoi is applied.
• Bituminous mastic is applied in 2–3 layers, ensuring a total thickness of at least 7 mm. In traditional Russian architecture, pine resin mixed in a 2:1 ratio with lime-pulverized was used instead of synthetic bitumen. Both materials are applied 'on hot'.
• While the mastic is still warm, two to three layers of birch bark or kraft paper are laid on it.
• Next, two to three layers of ruberoid are laid dry, with an overlap of at least 150 mm.
• The top two layers of ruberoid are further bonded together using heated bituminous mastic.

Waterproofing the Foundation in a Basement

When a house has a basement or cellar below ground level, the foundation walls must also be waterproofed. This is especially important when the foundation depth exceeds the level of the upper groundwater layers. Since any foundation material naturally absorbs moisture from the soil, the foundation walls must be waterproofed.

Externally, foundation walls are coated with a hot-applied bituminous mastic layer. It is recommended to apply two to three passes over the entire surface. Each new layer must be applied only after the previous one has fully dried.

The basement floor must also be protected from groundwater penetration. This is done by laying 25 cm of dense, homogeneous clay as the bottom layer in the floor structure. The clay is compacted thoroughly and covered with a 5–7 cm concrete layer. The concrete screed should be reinforced to prevent cracking.

After the concrete has cured for 1–2 weeks, and once it has gained sufficient strength, the next stage of foundation waterproofing can begin. This involves laying a two-layer mat of rubemast or ruberoid onto hot bituminous mastic. Over this mat, another 5–7 cm layer of concrete screed is poured, which should already be leveled for a finished floor or prepared for a floor system on joists.

Additionally, an elastic joint must be installed at the junction between the basement floor and foundation walls. The simplest way to do this is to saturate hemp with bituminous mastic and pack it into the joint. The external waterproofing of foundation walls should extend 50 cm above the maximum groundwater level.

If the basement has multiple windows for additional lighting, special sumps made of clay bricks and lined with compacted clay should be installed in front of these windows.