Despite below-freezing temperatures, winter construction is possible and can be high quality when the correct precautions are taken. While there are inevitable schedule delays due to high winds, snow, and extremely cold temperatures, winter construction is feasible. We’ve outlined the risks associated with this type of work, as well as the appropriate precautionary measures that must be taken to ensure a quality repair.
Generally, sealants (caulking) should be applied between 4°C and 40°C. Sealants can be applied below 4°C with specified precautions. Without these precautions the sealant may not adhere to the substrate material or the lifespan may be significantly decreased. Confirmation of sealant quality can be confirmed using field adhesion tests. To successfully apply sealant in cold weather, consider the following:
- Consult the manufacturer to determine suitable products and preparation for the expected temperatures. Some manufacturers advise the installer to heat the substrate just prior to application to achieve the desired temperature, while others prefer not to use this method to reduce risk of dew forming as the substrate cools.
- Sealant applied at lower temperatures will usually have a longer cure time because of the increased time it will take for moisture to evaporate from the product. For example, sealants applied at -4°C may take 5 days to become tack-free, when in summer weather it would take approximately 1 day. Protection or notices should be provided so no one disturbs the sealant during the curing.
- The substrate should always be cleaned and free of frost or moisture prior to application. To clean substrates, it is normally recommended to use MEK (methyl ethyl ketone), a high-quality solvent that is soluble in water, which can more effectively remove frost from surfaces. MEK is hazardous and should only be used on the exterior and stored safely.
- Whether installing sealants in the summer or winter it is always good practice to retain a third-party consultant. The consultant should review the work in progress and also carry-out test cuts once the sealants have cured to check bond and proper profile.
We often hear that there are two seasons in Canada: winter and construction seasons. We now know that the construction season can be extended year-round provided there are proper precautions taken. Proper quality control and third-party review is critical to protecting your investment on any construction project, and even more so if you are considering winter construction. By keeping a close eye on the forecast and taking proper precautions, winter construction can produce high-quality, long-lasting repairs.
Check back for Surviving the Cold – Winter Construction: Flat Roofing!
Shawna Smigelski, B.Sc.(Eng.), P.Eng.