Hairline cracks in a concrete slab are rarely a cause for concern.
Stress cracks in concrete walls.
98 of the homes in the united states have foundations constructed out of concrete masonry blocks or brick all of which tend to crack when there is movement and excessive stress.
Poor concrete mix rapid curing or possibly other states.
Concrete walls containing horizontal cracks are serious issues.
Plastic shrinkage cracks are typically very narrow in width and barely visible.
Within a year after construction hairline cracks about the width of a sewing thread commonly appear on the inside of basement walls most often near windows and doors or in the corners of the.
Measure the width of cracks with measuring tape.
Horizontal cracks in concrete walls however indicate poor wall designs or pressure buildup behind the wall.
Vertical vertical cracks in your concrete block tend to appear as your concrete cures.
Call in a structural engineer for an in depth evaluation.
While nearly invisible it is important to remember that plastic shrinkage cracks don t just exist on the surface they extend throughout the entire thickness of the slab.
Cracks less than 1 8 inch wide are likely stress cracks while larger ones are often more serious.
Concrete block walls can fall victim to a number of different types of cracks.
Several masonry patching products such as hydraulic cement do an adequate job of filling cracks in concrete walls.
The process will bring the particles closer together and create cracks that are often too small to cause any problems.
If the crack is simply an aesthetic nuisance you can cover it yourself without worrying about the structure of your home.
However these products can fail after a few years if your foundation or retaining wall continues to move slightly leaving you with little choice but to chip them out and start all over again.
In any case concrete shrinkage causes the concrete to develop internal stresses.
A crack in a slab of 1 8 inch or less is typically a normal shrinkage crack and not a cause for concern.
Concrete cracks due to inclusions photo above of shale and iron sulfide mineral pyrrhotite cracking.
The cracks might indicate a more serious structural problem.
In poured concrete foundations shrinkage cracks are usually due to conditions at original construction.
See details at pyrrhotite inclusion cracking.
Each type of concrete foundation wall basement slab floor slab or slab on grade crack is discussed and described with photographs below.
In areas with expansive soils clayey type soils there is usually more soil and foundation movement than in other areas.
