|Window Sills for Replacement Windows|
|Window sills are installed along the bottom of the window to allow the water to drain out away from the house=|
Homeowners can install the window sill of their choice at inside and outside of their window.
 Window Sills
Window sills protect the interior and exterior sill area from moisture and mold. They can be built using any number of materials and can fit the frame style of the window. Adding windowsills and trim to a window installation creates a customized, finished look.
 Interior Sills
Interior sills are generally built with wood or vinyl materials. They tend to be decorative. The type of sill will depend on the window frame material. Some homeowners create a sill from drywall but these sills are generally seen as ineffective. Interior sills may vary from deeper sills which are up to 10 inches in depth (and may be used as decorative shelves) or shallow sills of two to four inches in depth.
 Exterior Sills
Exterior Sills must be built from materials which are weather resistant such as bricks, stones or marble. They are generally four inches or more in depth to allow rain run-off.
 Sloped Sills
An exterior sloped sill is the best way to prevent water from draining into the house through window openings. A sloped sill involves a sloped rough opening surface on the sill. Along with a sloped sill, the window installer should also slope the sill plate which channels out water that leaks down from the top or sides of the window.
 Repairing Sills
If a sill has rotted or broken, it is important to repair the sill to ensure that water will continue to run off, away from the window. A self-draining sill pan or a backdam are good options for creating a system in which the water will drain to the outside of the wall.