Moisture-proof for houses and buildings

One of the causes for the structures of buildings and buildings is destroyed is water. There have been many traditional methods of moisture resistance, but the reality is not perfect, that is, moist air still penetrates the wall.

This problem is even more critical for old houses of special value.

When the waterproofing layer is destroyed, the underground water penetrates through the wall, destroying the outer plaster layer of the protective material and also the stone building blocks due to outside capillary seepage.

The frequent impact of moisture on the wood structures (beams, columns and other bearing structures) will gradually appear ' mold houses ' and only after a short time can it be damaged those structures. Mold grows quickly and penetrates any kind of building material easily.

Frequent wetness combined with heat in the basement and half-basement rooms facilitates the appearance of black mold markings. In old houses, fixing these phenomena will be very complicated and labor intensive.

We often see on walls of old buildings and new white speckles - that is, harmful salts such as Chloride, Sulfate and Nitrate groups. These salts have very special properties that they can absorb moisture even in the air, accumulate and release moisture. When this process is repeated many times, it will create crystalline salts. The bonding of new salt crystals with existing salt crystals will lead to the destruction of the wall material, which means that the plastering layer is peeled off, the mortar is uneven, bricks and all kinds of Other wall materials were also destroyed.

Normally, all construction materials have capillaries and water penetrates through these capillaries. To fill the capillary network in brick blocks, it is common to use special bitumen and waterproof mortar. But in long-term construction, capillary anti-capillary layer also lost its properties and uses.

Today, when repairing and renovating old buildings to prevent moisture from the soil from following the capillaries in the walls, hard metal shields or holes are placed. These holes are 30mm in diameter and drilled at 30 degrees, separated by 15cm along the surface of the wall on a certain base and have a depth equal to the thickness of the wall minus 8cm. The holes are then filled under a pressure equal to a special solution until the capillaries are saturated. Usually this process should be done at least 3 times. After filling holes, the solution needs to be cleaned. The solution will turn the mortar in the wall into an insoluble silicon compound and settle in the capillaries to make them narrow or completely filled. Thus, the capillary barrier will become a waterproof layer and the wet gas no longer has the permeability.

Examples of screen layouts (Photo: VNE)
a. Outside, on the ground
b. Inside of the basement room
c. Outside with the inner waterproofing layer
d.Both the exterior and interior of the house when the basement wall is built in double.

The construction of such screens can be done according to several options as follows:

- The screen can be built outside the house higher than the ground to prevent moisture from the soil. Making the masonry block under the screen always dry is difficult to guarantee, so in this case the inside of the wall and the protruding wall footprint should be reinforced with special mortar (see figure a ).

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Fix plastering layers instead of screens.(Photo: VNE)

The screen can be located on the inner wall of the basement rooms along with the waterproofing layer on the outside, so the surface of the wall is always kept dry if the external waterproofing layer is not destroyed or when needed can be repaired. In this case groundwater should be directed to a regular drainage system (b).

- The screen can be located on the outside with the waterproofing layer inside, under the influence of water under a certain pressure (c).

- The screen can be arranged on the open surface of the water in case of groundwater and standing water regularly. On the surface of the wall should be coated with an elastic waterproof layer inside and to avoid condensation of the steam, a special layer of mortar must be applied.

- When the basement wall is double building blocks, ie the thickness of the wall is 1m or more, the screen should be arranged both inside and outside of the house (d).

- When repairing thick walls, the construction of screens will not be economical. In this case, it is recommended to repair interior and exterior plastering layers (see picture).

According hau.edu.vn 'Housing construction' magazine of Russia, VNE