Repairs
Wood Rot on Trim and Fascia: How to Spot It Before You Paint
Where wood rot hides on Georgia homes, how to check for it with a screwdriver, what causes it and why it has to be repaired before the house is painted.
By Andrés R. Paz Barillas, Owner 3 min readPublished · Updated
Quick answer
Wood rot usually starts where water sits: fascia boards behind gutters, window sills, the bottoms of door frames and trim near the ground. Press a screwdriver into suspect spots — if the wood feels soft, spongy or crumbles, it is rotting. Rotted wood should be repaired or replaced and primed before painting, because paint will not hold on decayed wood.
Fresh paint can make rotten trim look fine for a season. Then the paint cracks, the soft wood underneath swells, and the problem is bigger than it was. In a humid climate like Atlanta's, checking for rot is one of the most important steps before an exterior repaint.
Where rot hides on Georgia homes
- Fascia boards: especially behind gutters that overflow or pull away from the house.
- Window sills and the trim below windows: water runs down the glass and sits on the sill.
- Door frames: the bottom few inches of exterior door jambs take splash-back from rain.
- Corner boards and trim near the ground: mulch, soil and sprinklers keep them wet.
- Garage door trim: the lower ends are close to driveway runoff.
- Where a roof meets a wall: missing kick-out flashing can send water down the siding.
The screwdriver test
Take a flathead screwdriver and press it into the wood at a few spots, especially low corners and joints. Healthy wood resists. Rotting wood feels soft or spongy, lets the tip sink in, or breaks away in fibers. Other clues: paint that bubbles or flakes in one spot, dark staining, mushroom-like growth, or wood that looks swollen compared to the boards around it.
What causes it
Rot is a fungus, and it needs moisture to grow. The usual sources:
- Clogged or overflowing gutters
- Failed caulk at joints, corners and around windows
- Sprinklers spraying the siding
- Bare, unprimed end grain on boards
- Soil, mulch or plants touching the trim
Fixing the cause matters as much as fixing the wood — otherwise the new board will rot too.
Repair or replace?
Small, shallow spots can sometimes be cut out and rebuilt with an exterior wood filler or epoxy system. When rot runs deep or covers a long section, replacing the board is the lasting fix. Many homeowners choose rot-resistant replacement materials such as PVC trim for the spots that stay wet the longest. Every new or repaired piece should be primed on all sides and caulked properly before paint.
Why it has to happen before painting
Paint is a skin, not a structure. It can't bond to decayed wood, and it traps moisture in boards that are already wet. Doing the carpentry first — by the same crew that paints — means the repaired areas are primed, caulked and painted as part of one finished system.
Key takeaways
- Check fascia, window sills, door frames, corner boards and trim near the ground first.
- A screwdriver that sinks into soft, spongy wood is the simplest test for rot.
- Rot needs moisture: fix gutters, caulk, sprinkler spray and soil contact too.
- Small spots can be rebuilt; deep or long sections should be replaced.
- Repair, prime and caulk rotted areas before painting — paint will not hold on decayed wood.
Frequently asked questions
Can you paint over wood rot?
No. Paint cannot bond to decayed wood and will crack and peel, often within a season. The rotted section should be repaired or replaced and primed first.
What is the best way to check trim for rot?
Press a flathead screwdriver into the wood at low corners and joints. If it sinks in easily or the wood crumbles, the board is rotting.
Should I replace rotted trim with wood or PVC?
Both work. Primed wood matches existing trim easily; PVC trim does not rot and is a good choice for spots that stay wet, like the bottoms of door frames and trim near the ground.
Related services: Wood Rot Repair & Replacement · Exterior Painting · Siding Repair & Replacement
