Installing a window stool in an interior window trim is not difficult and can add a lot to the look and value of your home. The stool acts as a small shelf on the inside of the window. While most people won't use this as a shelf for storage, it can be great as a separation between the window and wall for curtains and blinds.
Step 1 - Find the Measurements
The first thing you want to do is figure out how large of a stool you are wanting. The stool cap pieces will be available in several different styles, and they all have different lengths and widths. It's a better idea to visit a home improvement store and purchase a few small samples to give you a better idea. Then you go back and purchase what you need.
Step 2 - Have It Cut
If you have the measurements of the window with you, you can have the home improvement store cut it to the right dimension for you. This will ensure perfect square cuts.
Step 3 - Install the Cap
Place the cap in the bottom of the window, and tap it in place until it's snug. You can use finishing nails to secure it when you have a good fit. After this is done you can work on the surrounding trim.