Control joints

[Brent90Turbo]

I just recently purchased a home that has a detached 600sf garage that does not have any control joints cut into the slab. Garage was built 8 years ago. The floor is bare now but when I take possession I plan on doing an epoxy flooring. Should I be worried? From what I understand, the control joints are cut to reduce the risk of an uncontrolled crack during curing, and adding them at this point would only weaken the floor. GJ, please correct me if am wrong...

PS: home is in Quebec, Canada, so below freezing thermal cycles are the norm.

 

[wayne55]

No expert here, but if it hasn't cracked in 8 years, I would not touch it.

 

[Familyof8kids]

It depends on many factors in how it was pored, temp. humidity of the day during cure time, fiber additive, wire, vapor barrier, compact % of substrate, and many more.

With all of that said no matter what type of concrete you have 99.9% of the concrete slabs in the world WILL CRACK. Not how it cracked but when will it crack is for sure.

DO NOT CUT YOUR FLOOR. If it has not cracked in 8 years then you may get lucky. Cutting the floor will not help with anythig except allow the floor to settle in areas that may not have been aloowed when it was one piece.

110% when installing a new concrete slab have the installers install expansion and stress cuts. It is more important to prep the substrate than purchase the best slab technology.

If you build a firm foundation the house will be better.
If you clean the concrete surface very well the flooring will will stick better.
If you compact the substrate surface below the slab it will be less likely to crack.


It all starts from the bottom and goes up!

 

[Herb67SS]

A concrete contractor once told me there are only two kinds of concrete, concrete that cracks now, and concrete that cracks later.

 

[ConCretin]

Concrete contractors who use the old "there are two kinds of concrete" thing are just covering their ***. It's perfectly possible to construct a crack free residential slab - it just takes the right contractor and costs more than most people are ready to pay.

To the OP, control joints are most effective when the concrete is curing and has relatively low strength. If it hasn't cracked in 8 years, it's not likely to.

I would try to verify that you have a good vapor barrier before spending a bunch on epoxy.