Repair Water Damaged Wood Window Sill

How to refinish a stained water damaged window sash.

Repair water damaged wood window sill. Repair rotted window sill. Repairing window sills isn t a hard diy and i try to share simple ways to make diy improvements to your home. If you ve got badly weathered window sills you re not alone. Trim the back edge of the new sill as needed so that its lower edge fits tightly against the siding and its back edge fits against the old wood.

Restoring a sill ranges from the application of toothpaste and baking soda for water stains to the more labor intensive process of repairing rotting wood with epoxy primer and wood filler. Rot moving up vertical trim boards. Moisture problems are common on wooden framed windows. Wood that has been exposed to the sun s destructive rays for years without a protective layer of paint can begin to weather so badly that it may appear to be beyond saving.

Run a bead of waterproof marine grade adhesive along the old sill. A window sill is the bottom portion of the window and usually but not always has a lip that overhangs the trim molding and over time these can get damaged or even rot. Drill pilot holes every 16 inches or so through the new sill s front and back edges. While most wood rot starts at the window sill the length of time the damage is ignored will affect the amount of damage that needs to be repaired.

A water damaged window sill can however be brought back to its best with a minimum of knowledge or know how. Sand the wood with a fine grit sandpaper. Where the damage in the photo above is large it fortunately has not extended to either side of the vertical trim board. They have direct water exposure from the outside and sometimes condensation forms on.

Actual footage from a job repairing water damaged window sills. Most window sash and sill damage is caused by moisture in the form of condensation getting into the wooden window sill. But with the magic of a good wood epoxy you can save damaged wood like this and make it look like new. Remove any splinters and rough or peeling paint until the damaged sill is as smooth as possible.

Repair any rotten spots on the old sill with epoxy. Some paint can remain on the sills but it must.