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Residential buildings|Repairing cracks in walls and floors of private houses
10.03.2020

Cracks can occur in walls and floor of a house as a result of foundation subsidence due to weakening of subsoil.

In order to eliminate cracks, the reason why they occurred needs to be dealt with first, i.e. strengthen the soil and lift foundation to its designed height. This can be easily done by using URETEK geopolymers injection technology.

Among other things, the condition of a private house depends on the condition of the soil under the building. Foundation exerts pressure on the soil and may therefore gradually sink. The house remains stable as long as subsidence does not exceed permitted limits. If these limits are exceeded and foundation subsidence is uneven, it is necessary to take steps to solve the problem.

In case of foundation subsidence there is a danger of damaging floors, load-bearing and non-load-bearing walls, ceilings and partition walls. These structures may crack, window apertures and doorways may bend, utility lines break, etc. In cases like these, patching cracks in floor and walls is ineffective, because it does not eliminate the reason why they occurred – in many cases it is due to weakening of soil under the structure.

Soil weakening may be caused by irresponsibly performed construction works, e.g. insufficient compaction of soil under the structure. Naturally, there are cases where soil properties are altered because of breakage of water and sewer pipes or underground reservoirs. Weakened soil may also result from changes in surface water level.

Strengthening of soil and stabilisation of foundation

Traditionally, heavy machinery has been used to strengthen the soil under the structure and lift the foundation. Residents had to move out for the time of repairs and extensive earthworks were required to access the foundation. In that case, works performed for strengthening soil and securing foundation take 1–1.5 months.

Now, due to URETEK geopolymers injection method, soil can be strengthened, and foundation lifted with only two to three days. Meanwhile, there is no need for repairs and residents can remain in the building. All works related to geopolymers injection are performed outside the building, around its perimeter or indoors without using heavy machinery.

Geopolymers injection

There are two methods of URETEK geopolymers injection used for eliminating cracks in floors and walls of private houses. Deep Injection method allows lifting the foundation and strengthen the soil at remarkable depth. Meanwhile, Slab Lifting method makes it possible to lift concrete slabs on the ground floor by injecting geopolymer resin directly under the concrete slab, between slab and soil.

After injection, geopolymer resins expand quickly, filling all voids and cavities, strengthening soil and exerting vertical pressure. Resin achieves its final structure and hardens within 15 minutes. If geopolymers are injected in excessively humid soil, they force moisture out and strengthen the soil.

The course of lifting structures and eliminating cracks is monitored by using laser level with only ±1 mm deviation. Injection is performed though technical holes with diameter of 12–16 mm, bored in the concrete floor on the ground floor or in the ground around the building.

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