How to Repair a Rotten Window Sill

Have you ever started to paint an exterior window and discovered rotten wood? Our 1950's home has the original windows and several of our window sills need repair. Making the repair is relatively easy and can be done in an afternoon.
The first step in making the repair is to chip out the rotten wood with a 3 in 1 tool. After removing the rotten wood, scrape off any loose paint and wipe the window sill with a damp rag.
After the wood filler dries, sand it smooth. We recaulked our window, primed it, and painted it. One window down, six to go!
Paula Skulina
Want more details about this and other DIY projects? Check out my blog post!
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  • Amanda Hays Amanda Hays on Apr 20, 2021

    What is step-by-step instructions on how to repair a rotted window seal

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  • Edward Cogan Edward Cogan on Mar 09, 2014
    Excellent. Thanks for posting. It's a fairly easy DIY project to tackle. My daughter is buying her first home, and I get the feeling I will be "busy" - all great tips in this site. Great place.
  • M'sMammy M'sMammy on Feb 25, 2015
    Thanks for this idea. I looked at a different solution using epoxy on the This Old House site. That might solve some of the disadvantages of the Bondo.
    • Paula Skulina Paula Skulina on Mar 07, 2015
      @M'sMammy You are welcome! When it warms up I have a feeling that we'll have to use this technique on a few more windows.
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