Caulking in Cold Weather

By Murray Anderson

You've been meaning to apply new caulking around your windows all summer and there just didn't seem to be time. Well, 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.

But isn't caulking only supposed to be applied in warm weather?

• Latex caulking 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 caulk. 
   

So you just need to get a silicon caulk?

• Starting with a cold weather caulk is obviously important, but applying caulk in cold weather requires a little more than just getting a silicon caulk. 
• Make sure the substrate is clean and dry. In cold weather a thin layer of ice can form on the substrate and if you apply caulk on top 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 when it's cold, so it won't get right down into the joint.
• Store the caulking inside at last overnight before you plan on using it. On the job, you can keep tubes of caulk warm by putting them 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. All materials contract in cold weather and expand when warm. While wood is relatively stable, metal (aluminum) and plastics (vinyl) actually 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 murand@lycos.com.