Sill Slope and Weep Holes

By the time the second window is in, a good installer has already checked the drain paths on the first, and the intervals san bernardino window installers ncw india uses are shorter than the manual says. A window installation in San Bernardino, CA still needs a sloped sill and weep holes, because winter storms off the San Bernardino Mountains push water into every gap.

Why a sill must slope

A sill that is dead level or tilted toward the house holds water that gets past the sash. The sill is set to slope slightly outward, about a tenth of an inch per foot or more, so water runs off instead of pooling. A quick check with a level and a marble shows the direction of the slope.

Where weep holes sit

Weep holes are small slots in the bottom of the frame or the outer track. They let water that collects inside the track exit to the outside. Aluminum windows and sliders often have them near the ends of the sill. Covering them with sealant or paint defeats their purpose.

Keeping the path clear

Dust from the valley, along with Santa Ana wind debris, can fill the track and block the slots. A small brush and a vacuum clear them. Installers also check that the exterior sealant does not bridge over the weep hole, since a bead run across it traps water inside the frame.

Drainage behind the window

The sill pan beneath the unit catches anything that gets past the frame. It is lapped over the weather barrier so water travels out and down. A slider set in a pan that drains toward the wall cavity will leak within a season, even if the window itself is perfect.

Checking the work

A tablespoon of water poured into the track should leave through the weep holes within a few seconds. If it stands, something is blocked or the sill is not sloped. The same test works on single hung and double hung windows, and it takes less than a minute to do. Sliders are tested with the sash slid to each end of the track, since the water path is different at each end, and a window that passes with the sash in the middle can still leak at the corner.