The cause of "spalling" or "scaling" concrete is simple. Concrete is porous and soaks up a lot of water. When that water freezes, it expands and breaks up the concrete surface. Prevention is pretty simple too: Apply a sealer to reduce water penetration.
There are many types of sealers. For most sidewalks and driveways, the best choice is an acrylic sealer. Acrylics work by forming a clear coating on concrete. The coating is easy to apply with a roller or sprayer and will last two to five years, depending on weather and traffic. Some products give concrete a glossy "wet" look, while others leave a duller matte finish.
You'll pay $20 to $40 per gallon, and cost is often a clue to quality. Also check the label; higher quality acrylics are "nonyellowing" and require new concrete to be fully cured (14 to 28 days, for example). Acrylics cover 100 to 200 sq. ft., depending on the porosity of the concrete.
Home centers carry acrylic sealer (in the masonry aisle), though some sealers don't say "acrylic" on the label. A few common brands are Quikrete High Gloss Sealer, Quikrete Acrylic Cure & Seal, Rust-Oleum Concrete Sealer and Sikagard Sealer.
Acrylic coatings can make concrete slippery. So if you have smooth steps or walkways, there's an alternative you should know about: Penetrating sealers such as "silane" and "siloxane" create a barrier within the concrete rather than on the surface. Available only at specialty concrete suppliers, they usually cost more and degrade faster than acrylic.
— Gary Wentz, Senior Editor
The problem:Concrete soaks up water, which freezes and busts up the surface.
The solution:Apply a sealer to lock out water.
The result:The concrete looks just like it did before, but water beads up on the surface and doesn’t soak in.
Check out these related concrete repair articles from The Family Handyman:
- DIY concrete crack repair- Remove oil and other concrete stains- Concrete garage floor resurfacing
I agree with everything Gary said here...the only thing I would add is...a sealer won't stop concrete that is already falling apart from continuing to deteriorate. Once you get voids in the surface, water will sit in the voids, freeze and cause more concrete to pop and crumble. So if your concrete is falling apart already, be sure to address this first.
HI, I do agree with most of what had been mentioned, however there are also many
other things to consider regarding why concrete would flake, peel, spall or "pit".
Some contractors, add coloring agents to the concrete. If the coloring agents were not mixed in properly, that will play a big factor in the deterioration of the concrete surface & how fast it actually begins.
In colder climates, once salt or other ice melting products are applied to the surface, the problems start and take off pretty quickly from there. I've seen these such issues happen within the first year on occasion.
Other reasons for a failing concrete surface could be : too much water added to the mix & also too much air. Calcium which is in concrete also could cause the surface to fail. Some contractors add more calcium to the mix in order to make it dry faster in colder temperatures etc.
Protective Seal Coatings are always recommended for driveways, patios, walkway surfaces in all surface types. Asphalt, interlock, concrete, wood surfaces etc., all require proper surface protectors applied in order for the product to achieve its longest possible lifespan while at the same time maintaining a beautiful cosmetic appearance.
Keeping on the topic of concrete and seal coatings, Acrylic is the better known type of sealant to use however, water based sealants have come along way within the last 2-3 years.
The water based sealants are V.O.C compliant and they aren't as bad for the enviroment.
My company has been using acrylic sealers since we started sealing concrete & Interlock Stone surfaces about 15 years ago, but as V.O.C's are becoming a very strong issue, we are now beginning to use the water based products.
The same goes for asphalt or paved driveways. We have always used oil based sealants, as of this year, we started using the water based sealants. They're just as strong, dry much faster & the our warranties are able to remain the same (2 years)
When using the acrylic based products plain, the surface does remain somewhat slippery.
The solution to that is to have a polymer additive added to the sealant. Any sealer supply store, paint store & home improvement stores such as Home Depot, Lowe's & Rona, should carry the product. "Non-Slip additive"
Simply mix / stir it into the pail of sealant (1ltr of non-slip agent to every 5 gallon pail). Mix well and apply to the surface your sealing.
The best method of application that I have found is to spray the products on.This type of application will allow for a very even surface coating which also allows for an even wear when the products begin to extract or wear off. Two coats of sealer is usually recommended in order for the product to last atleast 2 years.
If using acrylic products, the dry time is normally 1-2 hours. two applications can definately be applied on the same day (weather permitting).
One thing to always keep in mind is that Acrylic Sealers enhance the appearance that your working on.
Concrete and interlock stone surface will have a wet look when complete.
If homeowners don't want this, they should be sure to tell that to their contractor.
If buying the product off the shelf it would be best to ensure that its a non color enhancing product that they are buying.
Thanks for reading & good luck with all your sealing projects.
John Catalano
The Sealer People Inc.
www.thesealerpeople.com
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