Specializing in hardwood furniture, trim carpentry, cabinets, home improvement and architectural millwork, Wade Shaddy has worked in homebuilding since 1972. Trim the ends of the sill with a router or chisel so they fit the dados on the jambs. How to Remove Garage Door Plastic Window Inserts. After dry-fitting everything, apply liberal beads of adhesive or caulk along the undersides and dado of the sill nose and slide it into place, matching the bottom dado to the outer edge of the jamb. When the saw comes into contact with the other side, turn it off and pull it free. As a result, the sill -- or its outside end called the "nose" -- often rots or cracks before any other part of the window frame begins to deteriorate. Pull or cut any nails out of the dados and remove nails or caulking under the sill clean to the bottom jamb or brickwork. Use a reciprocating saw to cut the remainder of the sill loose in both corners where the circular saw would not reach. The casing comes off to clear the way for removing the old sill. They are trimmed inside the window with a cap called a "stool" which sits on a base, called an "apron." Find the seam at the back, where the sill nose joins onto the jamb or spacer. No matter how much paint you apply to it, it won't help. Sand lightly, rounding the outer corners, then prime and paint with an oil-base exterior paint. The window sill supports the jambs which support the headers which support -- well, the entire wall eventually. Paint as needed. An avid perennial gardener and old house owner, Laura Reynolds has had careers in teaching and juvenile justice. If your exterior sill is showing any signs of damage, don't be intimidated by what appears to be a built-in piece of wood. Save the trim to use as templates for the new ones. Use a sill nose as an extension for a very deep sill or just the end of the sill that needs to be replaced. They are also the most exposed portion of the structure of the window, lying open to sun, rain and wind. Use a miter saw to cut the two-by-six fir to length. Remove caulking between the window frame and sill then clean out any caulking in the corners between the jambs and the sill. If the saw didn't cut all the way through the sill, pry harder to break it off and pull the sill free of the sash. If you use preserved timber, lay it flat outside to allow the preservatives to "vent" any vapours before using it or painting. Dry-fit the sill into the space and make any adjustments necessary to the blocks so the sill slides into the dados and sits level from side to side so water doesn't drain toward a jamb. Some window sills have a sill nose. Cut off any remaining pieces of wood that broke off under the trim with the chisel. Most sills are wedged between the side window jambs and tilt at about a 14-degree angle for good drainage. Remove the last few inches of the sill for a partial replacement. A retired municipal judgem Reynolds holds a degree in communications from Northern Illinois University. Dry-fit the sill into the space and make any adjustments necessary to the blocks so the sill slides into the dados and sits level from side to side so water doesn't drain toward a jamb. Pry both pieces up and out one at a time. (See below for tools and a shopping list. Her six children and stepchildren served as subjects of editorials during her tenure as a local newspaper editor. Fashion several supports for your new sill out of 5 by 10 cm (2 inch by 4 inch) blocks with slanted tops so the sill will sit on them with a 14-degree outward downward slant. Use coated or non-corrosive hardware to withstand rain, dampness and building materials' chemistry. Pound the new sill into place under the trim with a hammer, protecting the sill by placing a wood block between the sill and the hammer blows. 1 multimedia home enthusiast brand, offering trusted information and expert advice through award-winning television, a highly regarded magazine, and an information-driven website. Shaddy began publishing in various magazines in 1992, and published a novel, “Dark Canyon,” in 2008. This Old House and Ask This Old House are produced by This Old House Ventures, LLC and are presented on PBS by WETA Washington, DC.Follow This Old House and Ask This Old House:Facebook: http://bit.ly/ThisOldHouseFBTwitter: http://bit.ly/ThisOldHouseTwitterhttp://bit.ly/AskTOHTwitterPinterest: http://bit.ly/ThisOldHousePinterestInstagram: http://bit.ly/ThisOldHouseIGhttp://bit.ly/AskTOHIGTumblr: http://bit.ly/ThisOldHouseTumblrFor more on This Old House and Ask This Old House, visit us at: http://bit.ly/ThisOldHouseWebsiteHow to Replace a Rotted Windowsill | This Old Househttps://www.youtube.com/user/thisoldhouse/