How to Install Window Stools

Window stool molding adds a finished look to interior windowsills.

Window stool is an interior molding that trims the window sill at the base of the window opening. It is a decorative molding that is part of the overall interior window trim. Installing window stool is not a difficult task; however, attention to detail is important in order for the stool to fit correctly into place. Take your time and prepare the window stool carefully and you will have an attractive stool molding installed as part of your interior window trim.

Things You'll Need

• Tape measure
• Pencil
• Miter saw
• Scribing tool
• Sandpaper, 120-grit
• Hammer
• 1 box finish nails

Instructions

1. Measure the length of the window sill using a tape measure. Add two times the width of the side window trim to that measurement. This is the length required for the stool molding.

2. Place the stool molding flat on a work surface. Measure and mark the stool molding to the required length from step 1 using a pencil.

3. Set the stool molding flat on the table of a miter saw with the back edge flat against the fence. Align the pencil mark with the saw blade and guide the saw in a steady motion through the wood to complete the cut.

4. Insert the cut molding into place at the base of the window. There will be a gap between the back edge of the window and the back side of the molding. Adjust the scribing tool to the width of that gap. Run the scribing tool along both ends of the molding using the wall and window frame profile as a guide to transfer the profile onto the molding.

5. Cut out the scribed profile from each end of the molding using a band saw. Place the molding flat on the table of the saw and guide the molding through the saw as the blade cuts through the wood to complete each cut.

6. Sand the cut edges lightly in the direction of the wood grain with 120-grit sandpaper. Insert the molding into place at the base of the window frame. It should fit tightly against the window sill and window frame.

7. Hammer finish nails through the top surface of the molding into the base of the window frame. Space the finish nails every 4 to 6 inches along the length of the molding.

Tips & Warnings

• Make a cardboard template of the profile you need to cut out if you have several of the same size stool moldings to install.

• Wear eye protection when operating woodworking tools.

References

• This Old House: How to Trim Out a Window
• Gary M. Katz Online: Installing Traditional Stool and Apron