Where rot starts, and why
Rot is a fungus, and it needs wood that stays wet. It starts where water collects and cannot dry out: the bottom of door frames and brick moulding, window sills, the lower ends of trim boards, fascia behind overflowing gutters, and anywhere paint and caulk have failed and let water into end grain.
Rot in strata buildings
After the building-envelope failures of the 1990s, many BC condos and townhouses were rebuilt with rainscreen walls, and exterior trim, siding and windows are usually common property. If you live in a strata and see soft trim or water staining around windows, report it to your strata manager; the repair, and the cost, is normally the strata's.
How far does it go?
- Probe the wood with an awl or screwdriver. Sound wood resists; rotten wood is soft or spongy and the tip sinks in.
- Look for paint that bubbles or peels, cracks running across the grain, and staining.
- Check the edges of the soft area to see how far it extends; rot is usually larger than it looks from the surface.
- Look behind trim where you can. If the sheathing or framing behind is soft, the repair becomes carpentry on the structure.
Epoxy repair or replacement?
Epoxy works for small areas of rot in otherwise sound wood, especially on trim or historic details that are hard to replace. The rotten wood is removed, a liquid consolidant hardens what remains, and an epoxy filler rebuilds the shape, which is then sanded and painted. Replacement is the better choice when rot runs through a board or along much of its length. Replacing with rot-resistant material, such as cellular PVC trim or wood primed on every side including the cut ends, stops it recurring.
How trim is replaced
- Remove the rotted board and check the sheathing, flashing and framing behind it.
- Fix whatever let water in: missing flashing, a failed drip edge, gaps in caulk.
- Prime all sides and cut ends of new wood trim before installing, or use PVC.
- Fasten with corrosion-resistant nails or screws, caulk the joints, and paint.
What it costs
| Job | Typical cost |
|---|---|
| Minor rot repair Trim, a window sill or a few boards | $500–$1,500 |
| Window sill replacement | $150–$400 |
| Fascia repair, Metro Vancouver | $200–$800 |
| Fascia replacement | $600–$2,500 |
| Removing and rehanging gutters for fascia work | +$150–$400 |
| Handyman labour, Vancouver | $80–$110 / hr |
Stopping it coming back
- Keep gutters clear and downspouts pointed away from the walls.
- Repaint and recaulk exterior trim before the paint fails, not after.
- Keep sprinklers, soil and mulch off wood trim and siding.
- Check the bottoms of door frames and window sills every year.
Related: door frame repair and replacing deck boards.
Common questions
What is the difference between dry rot and wet rot?
Both are fungal decay and both need moisture to start. "Dry rot" describes wood that looks dry and crumbly at the stage it is found. The fix for both is the same: remove the decayed wood and stop the water.
Can I paint over rotted wood?
No. Paint over rot traps moisture and the decay keeps spreading underneath. The rot has to be removed or consolidated first.
Does home insurance cover wood rot?
Usually not. Policies generally treat rot as gradual damage or a maintenance issue. Rot caused by a sudden covered event can be an exception; check your policy.
Related guides
Compiled from published 2026 cost data (Metro Vancouver fascia and handyman contractors, window frame repair guides), in CAD. We update these figures as we complete jobs.