Window stool – Wood window stools or window sills get a lot of exposure to the elements, causing them to rot. When wood in your window stool cannot dry properly, deteriorating wood makes it soft and flaky. Rotten wood is structurally sound and should be replaced. Remove all window trim from the window before attempting this project.
Cutting window stool in the middle and two sides with a saw. Removing the middle of the stool by prying up on it with a crowbar. Slide the pry bar under the back of the side-pieces of the stool to pull them out from under the window jamb. So off any nails that remain in the window will open with a hacksaw. Push a piece of cardboard in the stool window opening to make a template of the window stool. Using the old footstool as a guide to the thickness of the stool. Take your template to a timber supply center to buy lumber to make a new window sill.
Replace a rotten window stool, Cutting new stool out of the timber by following your template. Facet top outside edge of the sill 10 percent using your old footstool as a guide. Sand down any rough edges with sandpaper. The lay a layer of insulation in between the lining and plaster boards of the sub frame at the bottom of the window opening. Attach the new stool in the window opening with 16 d finishing nails. Caulk gaps between the window frame design and siding with window caulk.