A sill is the horizontal masonry or stone piece set at the bottom of a window or door opening, sloped to shed water away from the wall instead of letting it sit against the opening or run down the face below.
Every window and door opening in a masonry wall is a break in the wall's water defense, and the sill covers that gap at the bottom. A proper sill slopes away from the opening and usually projects slightly past the wall face with a drip edge underneath, so water rolling off the glass or frame doesn't run straight down the brick or wick back under the frame. Stone and precast sills are common on masonry openings because they hold up to that constant wetting better than most alternatives.
A sill that's cracked, has lost its slope, or was set flush instead of projecting is one of the more common water entry points we find on older brick homes in the area. Water that pools on a flat or damaged sill has nowhere to go but down into the mortar joints below it, and over a freeze-thaw winter that turns into spalled brick right under the window before anyone notices the sill itself is the cause.
More masonry vocabulary from the glossary.
The services where this term comes up.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
