By LE Construction · Published October 6, 2026
Dry rot is fungal decay in wood. Despite the name, it only starts where wood stays damp: about 20% moisture content or more is commonly cited as the range where decay fungi grow. Near the coast in Oxnard, Port Hueneme, Ventura and Carpinteria, the marine layer and salt air keep exterior wood damp longer, so rot shows up more often and spreads further before anyone notices.
Where it hides in coastal homes
- Window sills and trim, especially on walls facing the ocean.
- Door thresholds and the bottom of door jambs.
- Fascia and rafter tails under clogged gutters.
- Deck ledgers and joists, where the deck meets the house.
- Sill plates in damp crawlspaces.
- Bathroom subfloors around toilets and tubs.
- Behind stucco where flashing has failed.
Why the coast makes it worse
Wood dries slowly in damp air. A wall that gets wind-driven rain, a planter that wets the stucco, or a deck that holds water stays damp for days. Salt air also corrodes fasteners and flashing, opening more paths for water.
How it is repaired
- Find and fix the moisture source: flashing, drainage, a leak, a sprinkler, poor ventilation.
- Remove all decayed wood back to sound material.
- Replace it with appropriate lumber, often preservative-treated where it will be exposed.
- Protect it with proper flashing, sealing and paint.
- Improve drying, for example by ventilating a crawlspace or adjusting irrigation.
Small areas, like a window sill or a section of fascia, are modest repairs. Structural rot in sill plates, joists or deck framing costs more and may need a permit.
Prevention
- Keep gutters clean and downspouts directed away from the house.
- Keep sprinklers off walls and soil below the weep screed.
- Repaint exterior wood before the finish fails.
- Keep crawlspace vents open and clear.
- Look for soft spots once a year.
See our dry rot and termite repair page and our guide to termite damage repair.
Frequently asked questions
Is dry rot actually dry?
No. The name is misleading. Dry rot is fungal decay that needs moisture to start and grow. The wood looks dry and crumbly once the fungus has consumed it, but the cause is always water.
Can dry rot spread to healthy wood?
It can spread through wood that stays damp. Removing the decayed wood and fixing the moisture source stops it. Treating the surrounding wood with a borate product can help where it is appropriate.
Is dry rot covered by insurance?
Usually not, because insurers treat it as gradual damage or a maintenance issue. Coverage may apply if the rot resulted from a sudden covered event. Check your policy.
How do I find dry rot before it gets serious?
Probe painted wood at window sills, door thresholds, fascia, deck ledgers and the bottom of trim with a screwdriver. If it sinks in easily, the wood is decayed. Check the crawlspace too.