Fixing Window Sill Wood Rot

Get rid of any rotted wood behind the apron and sill.

Fixing window sill wood rot.

Rot that occurs deep inside of the sill is more difficult to repair. Just fill the checks cracks and voids but don t cover the surface of the wood. Once removed any sections of the windows that were compromised with rot need to be treated with a two part timber treatment preservative. If the sill was pretty rotted there s a good chance that water worked its way in behind it and rotted siding and possibly even framing members.

Repair any rotten spots on the old sill with epoxy. Windows are an integral part of our homes allowing us fresh air and view of the outside world. Trim the back edge of the new sill as needed so that its lower edge fits tightly against the siding and its back edge fits against the old wood. The rot is often found when homeowners decide to install a.

The way to prevent this is to avoid skim coating window sills or other wood. This old house general contractor tom silva shares some tricks of the trade for installing a new long lasting windowsill. When we replace window sills and other wood trim that is most prone to wood rot we recommend using a composites like azek which has no wood content. The material costs more but eliminates the worry associated with not doing the required annual maintenance to avoid a repeat of the problem in 5 to 10 years.

It is therefore very important that you keep your windows in great shape so that they will last for many years. Like windows cracks and gaps between a door and the siding or threshold permit water to enter making them prime spots for wood rot. Set the depth of the router bit to create a stepped patch to fit into the window sill. If you notice that the wood around your window has rotted take care to address this as soon as possible.

This type of repair is common when replacing the window sill so together the repairs would take 2 to 3 hours plus shopping time as there are no standards for thickness of the window trim. Surround the damaged area with wood strips to serve as a router guide. Drill pilot holes every 16 inches or so through the new sill s front and back edges. John leeke covers the topic in depth in his book save america s windows which i recommend reading whole heartedly.

See below for tools and a shoppin. Use your chisel or multitool and get rid of any wood that s rotted crumbling or punky.