Caulking: Application Conditions and Shelf Life

What other things do homeowners need to keep in mind when caulking their doors and windows? The Ins and Outs of Caulking reminds us of two important factors: the conditions when the work is done and the shelf life for the materials.

thermometer2The range of acceptable application temperatures will be indicated by the sealant manufacturer. Emulsion (“latex”) sealants cannot be applied below about 40°F (4.4°C). Silicone sealants typically have the widest acceptable range of application temperatures. Surface frost, however, remains a concern when temperature at application is below freezing. High temperatures will accelerate cure time. In some cases acceleration can be excessive, and adhesion to substrates will be compromised if the sealant “skins” before tooling can be accomplished.

Sealant should not be applied during or immediately after a rain. Freshly installed joints usually can withstand modest rain exposure, provided that the sealant has first “skinned” and provided that raindrops do not forcibly impact the sealant. Latex sealants are more likely to be deformed by rain exposure shortly after installation than are other sealant types. It is good practice to refrain from installing sealant joints if there is a threat of rain within 3 to 6 hours. The acceptable time “window” will depend on ambient temperature and sealant type.

Shelf life is also important with caulk. Do not use caulk that has been stored for excessive periods. The caulk manufacturer may indicate shelf life on the product packaging. If it is difficult to force the caulk from the tube at normal temperatures, the shelf life has probably been exceeded. However, easy dispensing of caulk from the tube does not necessarily indicate product freshness. Some caulks that have exceeded their shelf life may be pumped easily from the tube, but will fail to cure. Latex caulk that has been frozen in storage should be discarded.