Some cities in Quebec offer subsidy programs for cracked buildings. Obviously, you must meet the eligibility criteria to be eligible for the grant. Thus, the causes of the subsidence of the foundations must be linked to the condition of the soil and not to a defect or a construction defect.
Cracks or shears are stair-shaped cracks in the exterior brick cladding. It should be noted that the exterior envelope, which is made of bricks, is very vulnerable to the movement of foundation walls and the subsidence of the ground under the building.
Subsidence of foundations
Normally, cracked buildings present a problem of sagging foundations. So there are, in general, structural cracks in the foundation walls. These are oblique and open cracks with a width of more than 1 mm and, sometimes, there is a displacement - on both sides of the crack - in the foundation wall.
The building is considered to be " cracked " if there is at least one structural crack in a foundation wall as well as a lizard (shear) in bricks. This crack and this crack must be the result of the subsidence of a foundation wall.
Cracked buildings and subsidence
Ground subsidence may affect all of the building's foundation walls or some walls. In some cases, we notice a partial subsidence which touches a wall or a corner of the building. Garages are particularly susceptible to partial subsidence due to possible problems with insulation and drainage of the foundation walls of the garage.
Mesurer sinking foundations
In all cases, at the places where there are structural cracks, in the foundation walls, and cracks in the bricks it is necessary to measure sagging foundation walls. Either this subsidence is generalized to all foundation walls or it is partial. This involves determining the extent of this subsidence on the integrity of the building structure and proposing an adequate solution. This can be to insert pious under all foundation walls or just under part of the building.
The subsidence of the foundation walls may be negligible or considerable. If ever the problem is major, this can cause damage to the wooden structure and various building elements such as doors, windows, floor joists, etc.
Cracks and cracks
Note that not all cracks and shear in bricks are caused by sagging foundation walls. Indeed, there are other deficiencies that can cause cracks in the bricks, such as corroded steel lintels or unreinforced concrete lintels (above the openings, etc.).
Also, not all cracks - found on foundation walls - are structural cracks caused by subsidence. There are several types of cracks which have different causes, such as concrete shrinkage cracks and cracks caused by lateral thrust from the ground, etc.
To quantitatively assess the subsidence of foundation walls, you need expertise with a structural engineer. The latter measures the subsidence, with a laser level, and checks the extent of the subsidence over the entire building and offers an appropriate solution.
The most notable subsidence is often found in buildings that rest on clay soils, as these have a low bearing capacity. In this case, the subsidence is likely to be generalized and to affect all the foundation walls.
In many homes, we find that the front section of the garage (near the garage door) presents a certain structural movement partial in the foundation walls. This movement, at this location, is the cause of the cracks and large cracks that are often found in the foundation walls of the garage.
Generally, in case ofsignificant sag foundation walls, excavate outside to the footings of foundation walls. Subsequently, piles are installed under the footings to support the walls of the foundations. At the same time, you must take advantage of the excavation to repair cracks, foundation walls and install a French drain. It is essential to fill the excavated trench with non-freezing materials (such as crushed gravel ¾ clean). At the end, the required exterior landscaping work must be carried out. It is also necessary to redo the displaced bricks and repair the cracks, to prevent water infiltration behind the brick facing.