Common Reasons for Cracked Concrete
Sub-base Issue– If the sub-base of the concrete wasn’t compacted all the way, it can cause the concrete to settle in one area rather than evenly across the entire surface. Eventually, the concrete will begin to sink to even itself out, causing a crack.
Cold Temperatures– Winter is one of concrete’s worst enemies. If the dirt under concrete freezes, it will expand and lift the concrete, putting enough pressure on the concrete to cause it to crack
Shrinking– Concrete shrinks when it dries. That is to be expected. But it’s when the mixture was too wet or not cured properly that the concrete can crack when it shrinks. To keep concrete from cracking when it dries, expansion joints should be cut into the floor.
Depending on the reason you may be experiencing cracked concrete, your repair may be temporary. If it is a problem with the sub-base, the concrete may need to be removed and redone. Repairing the crack will be only a temporary fix since the concrete is likely to shift again. If it cracked due to freezing temperatures, you may be safe until the next winter. If your concrete cracked due to an initial shrinkage, a permanent repair should be fine.
How to Repair the Crack
1. First, you’ll want to key the crack. This is done using a hammer and a chisel to undercut the edges of the crack so that the crack is bigger at the bottom than the top. This will create a more secure repair.
Tip: If the crack is very small or narrow, you may need to use a file to make the crack bigger in order to have a lasting repair.
2. Use a wire brush to clean out the crack of anything loose that may have fallen into the crack or have been knocked loose while keying it. To get a thorough cleaning, you can also use a vacuum to suck up loose particles.
3. Wash the area with water to clear away remaining dust or debris. If any oil or grease is on the area, use a strong cleaner to get rid of it before you make your repair.
4. Insert concrete repair resin into the crack.
5. Fill the crack with dry silica sand.
6. Saturate the sand with more resin to fill the crack to the surface.
7. Wait 10-15 minutes for it to dry, then scrape the area with a putty knife to smooth and level out the surface.
8. If the repair looks messy or feels rough, you can sand the surface down to make it clean and smooth.
If you still aren’t happy with the repair you’ve made or wish to have your concrete redone, consider us at Creative Concrete to do the job for you. From repairs to resurfacing, we know how to make concrete long-lasting and look good.