By Gene and Katie Hamilton
A window sill on the exterior of a house is not easy to replace because it’s an integral part of the window frame and is difficult to remove. Yet even if you’re not a master carpenter, you can repair a damaged sill by rebuilding, shaping and sanding it to conform to its original appearance
DIY Hassle Alert
The location of the window sill can be an issue. If it's on the second floor and you have to hike up a ladder or if the repair work is difficult to reach, the job may be more than the basic repair.
The material to use is a two-part wood filler and hardener from Minwax, or a wood filler and stabilizer from Bondo. Both are available at hardware stores and home centers. The filler is designed to fill holes and gouges in the wood, and the hardener or stabilizer is formulated to strengthen and reinforce the decayed or rotting wood. When the repair area is dry, you sand and smooth the surface so it can be finished with a primer and paint to match the existing finish.
A handyman will charge $240 to rebuild a window sill with these materials, which includes labor and material. But you can buy them for $65 and do it yourself, saving 73 percent. Before you begin the repair, remove any loose paint with a wood scraper, then use a putty knife to apply the filler or a disposable bristle brush for the hardener. To smooth the surface, use a pad sander and sandpaper before finishing the surface with a primer and paint.
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Home Advisor, a free referral service that connects homeowners with local prescreened contractors.
The bottom line: compare the price of a contractor’s bid torepair a rotten window sill with what it costs to do it yourself and make your decision. You adjust the cost to where you live by adding your ZIP Code.
Improvement and Repair Cost Updated 2020