Greetings!
Brrr! The weather may be frightful at this time of year, but in
many areas of the country, you can still place decorative concrete even when
it's cold outside. To be successful, however, you need to heed some
precautions. Actually, placing decorative concrete in cold weather is not much
different than when placing plain, unadorned concrete (see Precautions Before Placing Concrete in the Cold). But what if you
plan to use colored release powders, stains, or sealers on your concrete? Here
are a few tips to get the best results and avoid discoloration problems.
Jim Peterson,
The Concrete Network
|
Take the Concrete's Temperature
Keep a dial pocket thermometer or an infrared thermometer on hand to test the
concrete temperature. For
the concrete to gain strength, you need to keep the temperature above 50?F.
|
Don't Use Calcium Chloride
Don't be tempted to add calcium chloride accelerators to the concrete mix to speed setting time. They can give colored concrete a mottled, milky appearance. Instead, use nonchloride accelerators, which don't cause this mottling effect. (See Changes to the Concrete Mix During Cold Weather.)
|
It's OK to Apply a Colored Release
If you plan to stamp the concrete, you can still apply a colored release agent (either powder or liquid) as long as you take care not to scratch the surface when you put down the curing blanket.
|
Wait to Apply Stain or Sealer
If air temperatures fall below 50?F, it's best to wait until spring to stain or seal the concrete. "Those who choose to seal concrete at temperatures below 50?F increase
their risk of failure substantially," says our technical expert Chris Sullivan. For tips on using
sealers at or close to 50?F, read Sealing Concrete in Cold Weather.
|
Apply Curing Blankets with Care
To keep the concrete warm, always have curing blankets on hand in case the temperature plummets. However, you need to apply them with care to colored concrete to avoid getting a mottled appearance. Solutions include putting down a layer of landscape fabric first to create a breathable membrane between the concrete and the plastic of the blanket or to use wet curing covers. These blankets maintain constant dampness on the surface and are less likely to cause mottling. (See Methods for Curing Colored Concrete.)
|
