How Do the Weep Holes in Windows Work?

Weep Holes

• All types of windows, whether wooden, vinyl or aluminum framed, contain weep holes on the bottom of the sill's outside trough. Each window contains two weep holes. Weep holes are also found on doors and on some building exteriors. All serve the same purpose -- keeping water from entering the structure.

Basic Principles

• Water flows downhill, and that is the basic principle for any type of water drainage. The sills of most windows will slope down and away from the window. When it's raining, the water strikes the outside of the window, drops to the sill and drains away from the dwelling. If any water does collect on the sill, it drains out through the weep hole onto the ground. The same principle holds true for snow or ice melting on the window sill.

Replacement or Installation

• If replacing or installing windows yourself, make sure the weep holes are in the correct position, and don't install the window upside down or backwards. Weep holes can't function if placed at the top of a window or in the interior of the building. If painting or doing other repair work, take care not to paint or caulk over the weep hole.

Cleaning

• Weep holes can't function if they are clogged or dirty. Make weep hole cleaning a part of your regular window maintenance. Check the weep holes periodically, especially if anticipating a major storm or the beginning of the wet season. Remove all debris from the window, including dead leaves, insects, grime and dirt. If the weep hole clogs, open it by using a screwdriver, soft brush or similar object to poke the obstruction through.