How to Replace a Window Stool

What You'll Need
New wood for stool
Pry bar
Skill saw
Paint brush

The window stool, or window sill, receives a lot of wear and tear during the year because of being exposed to the rain, sun, and cold weather. After a certain amount of time being exposed to these elements, the stool will begin to absorb the water and rot. When this happens you will need to replace it. Here are the steps you can take to replace your window stool.

Step 1: Remove Window Trim

Before you can get at the window stool you will need to remove the trim from around the window. Pry it carefully so that you will not have to replace them. Use a thin pry bar and gently pry loose the trim pieces. If you make some marks on the board themselves you can touch them up with wood putty and paint.

Step 2: Remove the Apron and Stop Molding

These are the vertical pieces on the top and bottom of the window frame. Again, pry these up carefully so as to not damage them and need to replace them also. Use a small pry bar of the claw of your hammer. 

Step 3: Remove the Window Stool

Once you have all of the trim pieces removed you will be able to remove the stool. In a lot of cases the stool will be embedded very tightly and have to be pried out. You can also use a skill saw to cut small slits in the stool so that you can pry it out in pieces. If you need to, you can also use this piece as a template for the new stool. If you elect to do this you will need to be careful when removing it.

Step 4: Cut New Stool

Trace the old stool into the new piece of wood and cut it out. You can use a skill saw to do this and sand off the edges with a sander. 

Step 5: Install new Window Stool

Lay a bead of weatherproof caulking onto the section where the stool will go. Set the new stool into position on your window frame. Tap it into place with a hammer. Do not force it too much or you will leave indents on the surface. If it is not going to fit too easily, then sand down the edges a little more until it slides into place. 

Step 6: Nail in Place

Once you have the stool so that it will fit snugly into position you can then secure it with galvanized nails. Many people elect to nail it from the bottom so that the nail heads do not show. Pre-drill the holes so that the nails will rest under the wood. Fill in the nail holes with caulking, or wood putty, and smooth it out with sandpaper. 

Step 7: Paint new Window Stool

After you have finished with the installation of your new window stool you will need to replace the trim pieces and paint the window so that it is all a consistent color. Use an oil-based paint with a primer for better protection against the weather elements.