DIY Rotted Wood Railing Repair
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 DIY How to Fix Rotted Wood for Good!

DIY how to fix rotted wood address the window sill rot, the rot on wooden railings, and similar surfaces. To begin the process of fixing something, you must first identify what’s broken. This is a delicate process because you already know or have suspicion that there is rotten wood. Some signs of rotted wood might be it has started splitting, stick out or up, it literally may have begin falling apart or falling to the floor or ground.

How to Stop the Wood Rot?

So now that you have identified and located the rotted wood, you don’t want to just paint it or cover it up. This creates a nice environment for further rot to emerge. Ultimately, we want to first stop the rot and repair the rot. In my DIY experience, this requires removing a piece or a section of the rotted wood. Here I’d advise you to mark the spot where the rotted wood transitions into “good” wood that can be salvaged. Then, you guessed it! We would remove the rotted wood up until the salvageable wood.

Using Wood Filler

Next, we’d get some replacement wood and/or wood filler. It depends how wide or long the open space now is that will determine next steps. If the space is 1inch or smaller, use wood filler. If the open space is wider, then use a combination of replacement wood and wood filler. Depending on your needs, you might need to use the replacement wood as a wood filler, in addition to the wood filler. 

I use Bondo brand Wood Filler it’s $20.49 at Amazon (see below)

Another tip with wood filler is that you can use spray foam and go over it with wood filler. For example, if you were covering a lock hole in your door. You could spray foam in the hole to create a filler effect. Let it dry, then cut the excess like using spray foam on windows. Then cover it with a layer of wood filler.

What to expect when you use wood filler. So if you get Bondo, there is a quart sized amount of wood filler. There is a small tube of activator located underneath the cap. Mix a generous amount of filler with activator. The activator hardens the filler. This gives you a short working time up to around 15mins. (check the label) before it hardens. Once it hardens, it is literally solid as wood and you have to sand it to even it out.

Our goal in this post is to go from this:


DIY Rotted Wood Railing Repair
DIY How to Repair Rotted Wood Railing

 To this:

DIY Rotted Wood Railing Fixed
DIY Rotted Wood Railing Fixed

Step 1 Mark the Good Wood

Mark the part of the wood where the rotted wood meets with the “good” wood. Cut away the rotted wood. 

DIY Remove rotted wood
DIY mark and cut away rotted wood

To remove the rotted wood, you can use a reciprocating saw (that’s what I used). It’s $99 on Amazon (see below).

Step 2 Apply Wood Filler and/or Replacement wood

Depending on the size of the area you may need just wood filler or both replacement wood and wood filler to fill the gap from the rotted wood you removed. You do not need special replacement wood, it can be any piece of wood you have around or spare wood from another project.


DIY prepare replacement wood
DIY swap rotted wood with replacement wood
DIY placement of replacement wood
DIY position replacement wood
Now that you have the replacement wood positioned, you are ready to apply wo

Now that you have the replacement wood positioned, you are ready to apply wood filler to create the bond between the existing wood and replacement wood (see next step).

Step 3 Sand the Wood Filler 

Sand the wood filler so it is level with the existing wood. You also want it smooth so it can receive the paint. Note, paint it on a dry day. I painted it may be an hour before it rained and let’s just say it looked like it was never painted. To be clear, you can use an orbit sander or a corner cat sander depending on how big the area is. If it is the corner of a window or in a tight space, you’d use the corner cat to reach a smaller space.

Step 4 Be Proud

Congratulations DIYer, you just fixed your rotted wood!

Other Helpful Resources

DIY Window Replacement Installation

DIY Window Remodel & Removing an Old Window


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