Vertical Cracks Vertical cracks through foundations and concrete walls in the basement or under space are also serious. This is also a sign that high pressure levels press against foundation walls. Chances are that your foundation is about to fail. These small cracks can be the result of normal settlement or, possibly, differential movement.
Differential movement is usually due to varying humidity levels around or under the base, and the common reason for that humidity is inadequate drainage around the home. The location and direction of the cracks are essential. For example, a crack in the upper region of the base wall may be nothing more than damage when the base was filled. A long horizontal crack near the center of the wall (vertically) may indicate pressure on the wall from the ground.
A long diagonal crack may indicate base settling or lifting, especially if the crack is wider at one end. Cracks in concrete walls and slabs are common. They appear on floors, entrances, walkways, structural beams and walls. Cracking cannot be prevented, but it can be significantly reduced or controlled by considering the causes and taking preventive measures.
Most cracks shouldn't be cause for alarm. Concrete poured when the temperature is cold will have fewer shrinkage cracks than concrete poured when it is hot; and in general, the more water added when mixed for the first time, the more shrinkage cracks there will be. They are typically constructed by pouring concrete into metal or wood forms, and then the forms are removed once the concrete has set or hardened. For example, concrete finishers can add too much water to the concrete mix to make it more malleable.
This additional water dissipates or evaporates causing stress on the concrete that causes the concrete to contract. For example, a crack in the step only in the mortar between concrete blocks or bricks may be less of a concern than a crack that goes through the concrete blocks or bricks. Precast concrete walls: These are concrete walls built off-site, trucked to the construction site, and then placed in place. If cracks appear soon after pouring the concrete base, it is possible that the concrete was mixed poorly or poured too quickly.
Evaluating a crack in a concrete foundation wall is often different from evaluating a crack in a concrete block or brick foundation wall. A cold joint is where a batch of concrete is poured and it has started to set or has hardened and then another batch of concrete is poured against the previous batch. A more massive vertical crack can occur when construction contractors improperly prepare concrete foundations and when the wall had poor steel reinforcement when workers poured concrete for the wall.
