What goes wrong with window caulking & sills if you wait
Rotten sills and window trim
Sills are flat-ish surfaces that collect rain. Once the paint and caulking fail, water sits in the joints and the wood rots from the inside out. Rotted sills can let water drip straight into the wall below the window.
Leaks, stains and mould inside
Water that gets past the exterior caulking can run down inside the wall. You might see bubbling paint, stained drywall under the window, or mould on the window return.
Drafts and higher heating bills
Gaps around the frame let cold air in and warm air out. Many Lower Mainland homes lose a surprising amount of heat through poorly sealed window perimeters.
Condensation and blocked weep holes
Sliding windows have tracks and weep holes that drain water out. When they clog with dirt and debris, water backs up inside the track and can spill onto the sill and wall.
Common jobs we take on
- Exterior window re-caulking
- Rotten window sill repair
- Interior window trim and stool repair
- Draft sealing around window frames
How Lower Mainland weather affects window caulking & sills
Long, wet Lower Mainland winters mean window perimeters are tested almost every day from October to April. Wind-driven rain from Pacific storms hits windward walls hard, and in the Tri-Cities the extra rainfall near the mountains makes it worse. Many BC homes built in the 1980s and 1990s had window flashing details that relied heavily on caulking, which is part of why the leaky condo crisis was so widespread.
Inside, cool damp winters lead to condensation on windows, especially in bedrooms and bathrooms. That moisture sits on sills and frames and feeds mould. Summer sun and heat then dry out and shrink the caulking until it cracks, ready to leak again when the rain returns.
Warning signs to watch for
- Cracked, shrunken or missing caulking around window frames
- Peeling paint or dark stains on exterior sills
- Soft wood when you press on the sill or trim
- Drafts you can feel around the frame
- Water stains, bubbling paint or mould under the window inside
Maintenance tips
- Check the caulking around every window each fall
- Clean sliding window tracks and clear the weep holes
- Keep exterior sills painted and sealed
- Wipe up condensation and run bathroom and kitchen fans in winter
- Re-caulk every 5 to 10 years, or as soon as you see cracks
How G2 Home Services handles window caulking & sills
We cut out the old caulking completely, clean and dry the joint, add backer rod where needed and apply a high quality exterior sealant. Rotten sill and trim sections are cut out and replaced, primed and painted. We also clear tracks and weep holes so water can drain. If we see signs of water inside the wall, we show you and talk through options before going further.
Every job is backed by our written promise: a locked-in price before we start, we redo anything you are not happy with, and a one-year workmanship guarantee.
Window Caulking & Sill Repair near you
We are based in Coquitlam and take on these jobs across the Tri-Cities, Burnaby, New Westminster, Vancouver, Richmond and the North Shore. Got other small jobs too? Add them to the list and we will do them in the same visit. See small jobs & odd jobs.
Window Caulking & Sill Repair: frequently asked questions
How often should windows be re-caulked?
Most exterior caulking lasts 5 to 10 years. In the Lower Mainland, check it every fall and re-caulk any section that has cracked or pulled away.
Can you repair a rotten window sill without replacing the window?
Often yes. We can cut out and replace the rotten part of the sill or trim and seal it properly. If the window frame itself is rotten, we will tell you honestly.
Why do my windows have condensation in winter?
Warm, moist indoor air hits cold glass. Running fans, opening blinds and keeping air moving helps. Persistent condensation between panes means a failed seal, which needs a glass unit replacement.
