Caulking in Cold Weather Caulking in Cold Weather

You've been meaning to apply new caulking around your windows all summer but there just didn't seem to be time. Now, the temperature has dropped and the winter winds are starting to blow. Does that mean you have to put off your caulking job until spring? Not necessarily. You can still apply caulking in cold weather.

Isn’t Caulking Supposed to be Applied in Warm Weather?

Latex caulking specifically should only be applied in warmer weather. In fact, if you read the tube it probably says some like "should only be applied in a temperature range of 40°F to 80°F." However, there are caulks that can be applied in much colder weather, all the way down to -20°F. These high-performance caulks generally have a rubber or silicone base that won't freeze like latex.

So You Just Need Silicone Caulk?

Starting with a cold weather caulk is obviously important, but applying caulk in cold weather requires a little more effort than just getting the right type.

Make sure the substrate is clean and dry. In cold weather, a thin layer of ice can form and if you apply caulk on top of it, the water between the caulk and the substrate will prevent the caulk from adhering. You can use a hair dryer to melt the ice and warm the substrate or, even better, clean the substrate using either methyl ethyl ketone or acetone (available at home stores). This will not only get rid of the ice, but ensure the surface of the substrate is clean so the caulk can bond tightly.

Keep your tubes of caulking warm until just before you want to use them. Cold caulk—even high-performance, cold weather caulk—won't flow smoothly or easily, so it won't get right down into the joint. Store the caulking inside at least overnight before you plan on using it. On the job, you can keep tubes of caulk warm by putting them in a jar of warm tap water for a few minutes or keeping them in a portable cooler with a jar of warm water (or a hot water bottle) inside. Placing the tube on a heat register or even on the dash of your car or truck with the defroster turned on will also keep the caulk warm enough to flow smoothly.

Allow for movement of the substrate. Don't start caulking first thing in the morning; wait until mid-morning at least, as all materials contract in cold weather and expand when warm. While wood is relatively stable, metal (aluminum) and plastics (vinyl) actually contract and expand quite a bit with changes in temperature. This will give the sun some time to warm the substrates and allow time for this natural movement to take place.

Use a caulk with a high joint movement capability. This is expressed as a plus/minus number usually on the tube of caulking. Caulks fall into one of two groups, either plus/minus 12.5% or plus/minus 25%. Look for the plus/minus 25% as it can withstand more movement without cracking or splitting.

Murray Anderson is an experienced freelance writer over 500 articles published on the web as well as in print magazines and newspapers in both the United States and Canada. He writes on a wide range of topics and is a regular contributor to DoItYourself.com. He can be contacted at [email protected].

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