A window sill has the basic function of keeping away water from the walls and the window but there are times when an air cavity or space can be interrupted or blocked, leading to the accumulation of water and moisture in the window sill; to prevent this for happening, a window sill weep is very important.

Purpose of a Window sill weep

A weep hole is a small opening that is designed to allow water to escape that might have otherwise collected in the window sill. A weep flap further allows the window sill to function at its optimum best as it is a vinyl flap that covers the weep hole so the water escapes and insects can also be kept out, at the same time.

Allotment/placing of a window sill weep

A window sill weep slot in the sill member or the bottom, is accommodated in the sash frame of the window and provides an outdoor release to the rainwater that may infiltrate the building. Materials and workmanship by themselves are insufficient to ensure that the cavity wall performance is best at all times and so, proper detailing and correct placing of weep slots is necessary for window sills to serve their purpose. Even the cavity walls constructed with the finest materials by the most skilful masons can suffer the results of poor detailing like the allotment of weeps.

Window sill weep adds value and life to a window sill

A window is subject to harsh and demanding weather conditions and change of environmental factors so is prone to wear and tear due to the elements of nature. It needs the protection of a window sill to keep away rainwater and the sill in turn, needs weeps installed in the exterior masonry wall construction to collect and divert moisture that penetrates the outside of the sill and wall. The air space separating the masonry must be kept clear of mortar droppings and other obstruction that may bridge air space, for which good workmanship is a strong asset. This will add life and durability to the window sill and keep it working as best as it should.