Ask the Contractor: What you should do to preserve your concrete
Our recent winter storms brought picturesque scenes and a chance to play in the snow, and I am sure many friends enjoyed sitting around a warm fireplace.
But with the snow flying, out came the salt and deicers on sidewalks and driveways. And now there has been an increase in phone calls pertaining to concrete issues.
“Our concrete is starting to flake.”
“Rocks are popping out of our driveway.”
“Our driveway looks rough.”
“Did we use the wrong type of deicer?”
“Our sidewalk has deicer stains.”
And the calls continue.
Here are some care techniques to help you out should we have another “snow spell.”
Why do spalling and pop-outs occur?
The freeze/thaw cycle is the build-up of water (melted ice) being absorbed into the porous concrete and then freezing and expanding. This expansion causes pressure to build up; it eventually will exceed the limit that the concrete was built to withstand, and when the pressure becomes too much, scaling occurs.
The concrete absorbing the melted ice (water) is a fact of nature and cannot be blamed on the deicer. However, when deicer is used you have more melted ice and therefore the potential for more water to be absorbed into the concrete.
When deicer is used, remove the slush from the driveway or sidewalk as quickly as possible. This will reduce the amount of water that may penetrate the concrete.
Another way of reducing the damage caused by freeze/thaw is to use a deicer that will keep melted ice in a liquid state for a longer period of time. Deicer products containing ammonium nitrates and ammonium sulfate are especially harmful because they will actually attack the concrete chemically.
Did you know that calcium chloride tends to leave an oily residue on the concrete, which is the cause of stains/discoloration?
I was walking up my driveway the other evening and a “rock” popped up. I looked down and could see the pop-out where a small concrete fragment had broken away from the surface. This area of the driveway was where water had frozen and was saturated with snow melt. I neglected to remove the frozen water/snow because it was not in my major drive/walk pattern on the driveway. I admit, I did not properly minimize the surface area to prevent this issue from occurring.
Pop-outs and scaling issues can be repaired. The damage can be patched, or a thin-bonded concrete overlay can be applied to cover up cosmetic flaws.
Diversified Concrete Crafters owner Brian Peterson confirmed that the risk of concrete damage can be “reduced substantially” be remembering not use deicer on new, damaged or unsealed concrete. Damaged concrete will absorb the water more readily since its seal has been broken.
It is recommended for concrete less than 12 months old that NO deicer be used. Newly poured concrete needs time to cure and settle. The application of deicer on concrete less than 12 months old may weaken the concrete structure making it more susceptible to damage in the future.
We also talked with Brian about sealers. He said “a sealer may prevent or reduce the amount of damage that occurs from the use of deicers. Even with a sealer applied to concrete, deicer use should be kept to a minimum.”
Remember, most sealers wear off over time and they need to be reapplied periodically.
Give your concrete love!
Remember to tune in to YCCA’s “Hammer Time” at 7 a.m. every Saturday and Sunday on KQNA 1130 AM, 99.9 FM, 95.5 FM or the web kqna.com. Listen to Sandy to Mike talk about the construction industry, meet your local community partners and so much more. What a great way to start your weekend.