Concrete Slab Foundation Problems and Defects

Unless you have problems your concrete slab foundation is something you probably don’t really think about. However taking some time to give it a look over even when there are no major issues could save you in the long run.  Small defects can lead to serious problems. It is best to catch these issues before they become a nuisance and money drainers.  It is essential to know just how important a concrete slab really is.  Remember that it is responsible for stabilizing your entire home.  Issues with concrete slab foundation should be dealt with as soon as possible.

Don’t get me wrong concrete slabs are quite durable.  They are very strong and do not need much maintenance. Also note, that some cracking may not be a big deal.  But there are other cases where small fractures can lead to major problems later.  Some situations require that things are dealt with as soon as they are identified.  Here are some common defects and descriptions of what is going on when you see them.

Concrete slab foundations are known to have three main types of cracks: shrinkage cracks, settlement cracks, and frost heave cracks.

Shrinkage cracks are a result of a change of moisture in the concrete slab.  Concrete is by nature porous and therefore contains small empty spaces.  These spaces expand when they absorb moisture and shrink when the moisture dries.  Shrinkage cracks occur when the concrete dries.  These cracks are not that serious because they do not indicate structural damage.  However, these void spaces can sometimes be an entryway for radon and water entry.

Settlement cracks are a result of inadequate site preparation when the concrete was poured.  Small cracks may appear along expansion points and may be relatively harmless.  In worse case scenarios soil settlement under the ground can hollow out space under the floor causing the collapse of the floor structure.  Because the severity of these cracks differs dramatically it is important to get them looked at to determine the size of the problem.

Frost heaves are the most destructive cracks.  They cause uneven and cracked flooring as a result of soil expansion pushing part of the floor up while the rest of the floor down is left down.  They put the whole house’s foundation at risk and need attention as soon as possible.

Blisters happen when air gets trapped underneath an already sealed slab surface.  They are typically fixed during installation but some blisters may still be found after.  Blisters are more of a harmless defect than a problem.  They do not cause any structural problems so nothing to worry about with this kind of defect.

Curling happens when the corners of your concrete slab foundation rise up.  This occurs because the top dries out and shrinks faster than the bottom wetter part.  Installers will typically deal with this problem before it becomes a defect during the drying of the foundation.  While a quality contractor like Brosco Concrete would never allow such a defect to occur during construction the same cannot be said for all installers.  If you find curling on your concrete slab call us.  Left unchecked curling can lead to significant cracking over the years.

Scaling is when the surface of the concrete degrades taking of 1.5mm to 10mm of depth off of its surface. This is usually due to poor surface strength.  However there is no clear reason for the cause. The blame game ensues, it was the homeowner, it was the contractor, it was the redi-mix company, or it was the finishers. The main issue with scaling is that if left unchecked coarse aggregate can eventually become exposed and could start falling out in chunks. There are methods to both prevent and repair scaling and these treatments are highly recommended.

Because defects and their severity are not always easy to identify it is always best to call in a professional when you see anything abnormal in your foundation.  What may appear minor could quickly grow into a much larger issue and there is no telling how long of short that time-line may be.  Address your issues and call in Brosco Concrete for an inspection as soon as possible.