Some professionals estimate that an unsealed 1/8-inch gap in a door or window contributes to as much energy loss as a window that’s left open six inches wide throughout the entire winter. The best way to prevent this problem is to carefully seal gaps and cracks with a high-quality elastomeric caulk. Before taking on a window or door caulking project, consider the following tips:
Identify problem areas. Sometimes it’s obvious to see areas that need caulking, but as a general rule, apply a bead of caulk anywhere two dissimilar materials meet (brick and wood, wood and glass, wood and metal).
Scrape and sand the surface. Fresh sealant adheres best to clean surfaces, so remove any old caulk before starting. Prime the area and allow it to dry. Technically, it’s possible to apply caulk to raw wood or masonry, but applying it to a primed surface yields much better results.
Windows
• Caulking window trim at the top and sides and leaving the bottom unsealed will prevent dripping and windblown water from entering your house while simultaneously allowing condensation to escape.
• Untrimmed windows require a bead of sealant around the entire window. Place tape on the window 1/8 inch away from the gap to assure a straight, professional-looking bead.
• Clear elastomeric caulk is less visible than the white variety but provides the same benefits. Don’t be alarmed if it goes on white—it’ll become transparent as it dries.
• Wood windows usually consist of multiple pieces, which produce more gaps that need to be sealed. Make sure to caulk any place where two pieces of wood join together, like where the trim meets the siding, the header trim and the sill.
Doors and frames
• All doors (entry, garage and pet) need special attention. Problems often occur where the doorframe meets the threshold, so apply a thin bead of caulk to prevent water damage. Also, caulk the areas where the trim meets the doorframe or siding.
• In garages with concrete floors, the frame can soak up moisture from the floor, which causes peeling. Apply a small bead of clear caulk to prevent this from happening
• Paneled entry and garage doors require a very good seal. Make sure you sand and prime all the panels before applying caulk (this includes any panels on wood and Masonite garage doors).
