How to Replace Rotted Wood Around a Window

Wood accents on a home add warmth and personality, but they inevitably will deal with some sort of wood rot later on. Wood rot is unavoidable for the most part, but once you identify serious wood rot, you should work quickly to rectify the situation to preserve the integrity of your home.

One of the areas you should be especially cognizant of is windows. A rotted wooden window frame can let pests and water seep in, and the spread of rot may continue.

Replacing rotted wood around a window is a project many homeowners like to take on themselves. If that sounds like you, here’s what you need to know about how to do it DIY-style!

Signs of Rotted Wood Around a Window

First, you’ll need to know what you’re looking for before you get out your tools and start ripping out wood.

A few things to look for include:

  • A gutter nearby that may be clogged
  • A wall leak beneath the window frame
  • Peeling paint
  • Trouble opening or closing the window from swollen wood
  • Developing mold smell or visible mold
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You might not even realize you have wood around your window, but noticing the signs of rot and acting quickly is imperative to controlling the problem before it gets worse.

Your Options

There are a few ways to handle the replacement of a rotted wood window frame. Some people prefer using epoxy wood filler to repair minor wood rot, but this tactic doesn’t work well if there’s a lot of damage.

The other popular method is installing replacement wood pieces to create a full-frame replacement. This method is best for extensive damage, as it can include replacing other components such as jambs and casings.

Materials Needed

Before you begin taking apart the rotted wood, you should ensure you have all of the needed materials on hand. Go shopping before you start any of the work to avoid any mishaps.

Some items you’ll want to have at the ready include:

  • Chisel or flathead screwdriver
  • Pry bar
  • Drill or claw hammer
  • Circular saw
  • Epoxy wood filler
  • Epoxy wood consolidant
  • Nails
  • Putty knife
  • Utility knife
  • Sanding block or sandpaper
  • Primer
  • Paint
  • Paintbrush

Once you have all of these items handy, you can get started on your removal and repair project.

Step-by-Step Process:

The step-by-step process looks slightly different depending on whether you’re using the epoxy method, or the total removal method.

If you’re using the full removal method, skip steps 4 and 5, and jump straight to step 6 after completing step 3.

If you’re using the epoxy method, use steps 1-5 only.

1. Scope Out the Damage

First, you must take a close look at the damage to the window to gauge its severity and determine which method of repair is best for your situation.

Get down and dirty by using your pry bar or chisel to remove as much wood as you can. It should be soft and crumbly if it’s rotted. Then, you’ll have a better picture of the real damage.

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If the rot is deep, then a more extensive repair job may be necessary. If it’s shallow, epoxy may be enough.

2. Mark the Window’s End

If the rot hasn’t extended much past the window into the siding, you will want to protect this area during your repair. Use the putty knife to make an approximate mark where the window ends and where the siding begins so you don’t remove or damage it during the remaining steps.

3. Clean Out the Gap or Remove Rotted Wood

You will then either clean out the gap from the wood you’ve removed or take out all of the rotted wood altogether.

If the damage isn’t bad, simply clean out the gap with your hammer and chisel. Clean it out until only solid, dry wood remains.

If the damage is extensive, you may need to use your pry bar and hammer to completely remove the rotted wood planks.

4. Fill with Epoxy Wood Filler (If Using Epoxy Method)

If using the epoxy method to fix a small area of rotted wood, first, cover the area with epoxy wood consolidant and let it dry. Then, apply the epoxy wood filler to the areas where you removed wood to restore the window frame to its original dimensions.

Try to mold the filler to match the natural shape of the window frame, using a putty knife to refine it. Then, let the area dry for at least 24 hours.

5. Sand and Paint Area (If Using Epoxy Method)

Once the epoxy has dried overnight, you can sand and paint the area to match the rest of the window. First, sand out any rough edges and try to match the window shape as close as possible.

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Then, use the same shade of paint and paint the new piece. You may want to add a final coat over the entire window frame to smooth out any edges.

6. Measure Removed Wood Portions

If you’re replacing full pieces of wood from the window frame, measure the size of the pieces of wood you’ve removed to gauge the approximate size for the new piece of lumber.

7. Cut New Lumber

Use your measurements to cut new pieces of solid, dry, and healthy lumber. You will need to fit it and make adjustments as needed.

Cut New Lumber

8. Paint and Prime New Lumber

Before installing the new lumber, you’ll want to prime and paint the new pieces so they can dry before setting them in place. The primer will also act as a barrier to rain and help the wood stay dry for longer.

9. Secure New Wood Pieces

Install new wood pieces using your drill and sturdy nails.

10. Caulk and Final Paint

Use caulk to patch up any open gaps or holes in the window sill, and apply a final layer of paint to blend the new and old pieces together.


How big of a project is this?

It can be done at home by yourself over a weekend.

How big of a project is replacing rotted wood from windows?

Does bleach stop wood rot from spreading?

Bleach will kill the mold fungus that causes rot, but it will not do anything to repair the wood that has already rotted.

How much will it cost me to replace wood rot around a window?

Replacing wood rot around a window will set you back a few hundred dollars, depending on the extent of the damage.


There you have it – the process of replacing rotted wood around a window is quite simple. If you have the time, patience, and willingness, it’s a simple enough project to do on your own with these step-by-step instructions.