Each type of concrete foundation wall basement slab floor slab or slab on grade crack is discussed and described with photographs below. As it dries the concrete begins to shrink. These cracks are part of the natural drying process for concrete.
Another common cause of cracks in basement floors is when the concrete slab begins to settle.
Cracks in concrete basement floor. While under construction the basement floor isnt heated in the winter and the dirt under the concrete freezes causing it to expand. If you find cracks in the concrete of your basement dont panic. Be they straight jagged or spiderweb like fine cracks in the basement floor commonly result from surface shrinkage as the concrete dries. If no expansion joints are cut into the concrete floor then shrinkage cracks will likely appear.
Oct 30 2012 by matthew stock. Concrete cracks due to inclusions of shale and iron sulfide mineral pyrrhotite cracking. The typical basement floor. Other types of concrete cracking such as due to impact or loading are discussed in other articles at this website.
These types of cracks can show up as long as a year after the basement floor is poured depending on how quickly the slab dries and how humid the basement is. Newly poured concrete shrinks when it dries. These are quite common. Often they use wire mesh as reinforcement which keeps concrete pieces together but doesnt prevent cracks.
Basement floors on the other hand rarely use rebar and typically run 3 to 4 inches thick. Many professionals advise that these types of hairline cracks are just superficial and do not require repairs as there. Tackling them upstairs is hardly the right place to start when theyre reproducing themselves constantly in the floor below. The sub base wasnt properly compacted and the concrete settled in one area causing the basement floor to sink and crack.
A spider web crack versus a straight hairline crack makes it no more dangerous. Small cracks in the basement floor commonly result from shrinkage as the concrete dries which pulls the concrete apart. Although it may seem daunting repairing cracks in your basement floor is something you can do without going to the expense of hiring a professional. Why cracks in basement floors cant be fixed by urethane injection.
The most common cracks found in your basement slab are the hairline cracks the shape or pattern of the crack is irrelevant. The stress released by the shrinking process causes the cracks. Typically settlement occurs when the soil beneath your foundation is too unstable to support the weight of your home and it shifts. They typically show up two to 12 months after the.
In extreme cases wide cracks can even harbor snakes. Concrete floor cracks are perfect breeding places for ant and termites from where they can fan out everywhere in your home. There are a lot of variables. You will begin to notice hairline cracks within 12 months of the basement floor being poured.
These cracks generally occur due to surface shrinkage as the concrete dries. Basement floors crack for a many reasons. Thankfully this is uncommon especially here in toronto. The sub base heaves.
That may explain why your slab has fared so well vs.
