How to Replace Rotted Wood Around a Window: A Complete Guide


Wood window frames can become rotted over time, and you might want to replace them. Various methods exist, including wood filler epoxy for minor rots, replacement pieces for extended decay, and complete window replacement for deterioration beyond repair. It would help if you had the right tools, including a chisel. Here is a quick guide on Replace Rotted Wood Around a Window.

Method 1: Repairing Minor Rot with Epoxy

  • Determine the extent of the rot

Use a screwdriver or your fingertips to inspect the wood for spongy areas. If the wood rot is less than 20%, it qualifies for epoxy repair. Check for other decay signs, too, such as peelings and discoloration.

  • Remove the rotten wood.

Use a  chisel to scrap the rotted areas; don’t damage the surrounding wood. Remove all the rotted sections, as unremoved regions could spread the rot to other parts. 

  • Prepare wood epoxy filler.

Mix up the two bonding components of epoxy in equal parts. Prepare enough filler to cover the scraped-out areas on the wooden frame. Be careful to work on a surface that won’t let the filler stick behind.

  • Apply the filler

Use a putty knife to apply the wood filler epoxy to the damaged spots. Then glide your putty knife over the repaired area to obtain a smooth finish. Epoxy starts to dry up within 60 minutes of mixing it.

  • Let the filler rest for up to 4 hours.

During this time, the epoxy wood filler will expand as it fills out extended areas. It would be water-tight, refrain from touching the stuffing as it dries up; you could end up deforming it.

  • Begin the sanding process
Sand the window frames.

Sand the window frames.

For effective results, sand the epoxy in tight, smooth circular movements. While you should commence with a 180-grit sheet, a 120-grit sheet will help with finer details. Wear a face mask and eyeglasses to guard yourself against dust. 

  • Paint the patched surface

Apply up to 3 coats of paint to the epoxy and the surrounding wood surface, letting the area dry up between coats – as recommended. Wait for 24 hours (or more) before modifying the repaired area.

Method 2: Installing Replacement Pieces for Badly Rotted Wood

  • Inspect the wooden windows to determine the degree of the rot

Use your fingers or a small hand tool to press along the edges of the wood frame, paying attention to spongy areas. These sections will likely show other decay symptoms – peeling, chipping, splintering.

  • Remove the rotted pieces.

Use a pry bar to loosen the rotted areas, then pull them out with your hand. When it comes to pieces, you can’t budge barehandedly. Use a skill saw or reciprocating saw to ease the job. It entails making shallow cross cuts into the wood before forcing out the sections with a prybar.

  • Measure the pulled-out pieces

Use a tape measure to determine the thickness, length, and width of the individual pieces you removed from the window. Your replacement pieces will need to match these dimensions.

  • Check for any cracks around the window.

Seal any visible openings before proceeding to install your replacement pieces. Use caulk on medium-sized cracks and spray foam insulation on larger cracks. Install adhesive flashing on any surrounding sheathing that exhibits signs of water damage.

  • Cut sections of new wood

Cut your replacement wood frames, matching the measurements to the pieces you initially removed. Make seamless cuts that will slide into place without the need for further modifications.

  • Install the new pieces

Use galvanized nails to secure the pieces, paying attention to each piece’s top and bottom corners. Experts recommend utilizing 8D finishing nails for this reason. Use wood putty to fill any sunken nail holes.

  • Paint the replacement sections
Draw an old window frame.

Draw an old window frame.

Apply at least 2 coats of paint to the replacement pieces, ensuring the shade matches the surrounding wood. Allow each coat to dry for some time before applying the next one. Then let the last skin dry for 24 hours.

Method 3: Window Replacement for Extensive Rot

Extensive rotting wooden window frames.

Extensive rotting wooden window frames.

  • Probe the window for signs of decay

Use a reliable hand tool or your fingers to press into the entire window frame. Check for any spongy,  peeling, or chipping signs – touch-test every piece so you don’t miss a spot.

If the rot is irreparable, your best bet would be to consider a complete window replacement.

  • Reach out to an expert

Unless you’re an expert in the game, replacing a whole window frame, including glazing, can be difficult on your own. So, while it might be costlier, please get in touch with a professional to help with this.


Now we are sure you know what to do if the wood around your window gets rotted. If you have any questions, feel free to contact us

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