Maintenance is the key when it comes to avoiding leaking windows. Virtually every window frame, whether aluminum, vinyl or wood, has a simple water drainage or "weep" system. It is normal for water to accumulate in the track in a wind-driven rain and then drain to the outside through the weep system. To allow this drainage to occur as designed, keep the sill or track areas of all windows and patio doors free of dirt, sand, sheetrock particles, dead insects, etc. For mechanically joined (screwed together) frames, be sure corners are caulked to prevent water penetration to the interior.
Once a year before the rainy season, check the sill to insure that the sill remains clean. Vacuum to remove debris in the sill. Check the sill for good sealant adhesion. Some locations on the window to check would be the jamb corners at the head and sill or the joints between the center post and the head and sill. If necessary, re-seal these joints with an acrylic small joint sealant. This sealant is available at a local window store. Remove the screen during this cleaning process so that the screen track area in the sill is cleaned and scaled. Clean out your window and door "weep holes" using a small, soft bottlebrush. These weep holes are visible on the inside track areas (both the vent track and screen track) as well as the exterior sill surface of the frame. Be careful not to damage exterior weep hole covers or baffles. Weep holes must remain clean and clear to properly drain water to the outside.
Check weather stripping around operable window and door panels. Clean and fluff the weather strip each year before the rainy season. Make sure it is not excessively worn and seals evenly.
By taking a few minutes and following a few easy steps you can help prevent your windows from leaking and causing water damage to your home.
Check every 6 months or sooner:
Check for condensation.
Check for mold.
Security, hinges and operation.
In some areas, clean the frame surfaces.
Check once a year (before rainy season):
In all areas clean the frame surfaces.
Clean sill track and weep holes.
Check for sealed joints.
Check for properly operating hardware.
Check for roller operation.
Check the weather strip.
KEY DO'S AND DON'TS
Do clean the frame surfaces;
Don't use a razor blade, putty knife or abrasive pad.
Do use a glass cleaner or mild detergent;
Don't use any petroleum-based cleaners or solvents.
Do clean tracks and weep holes;
Don't use oil-based lubricants or damage weep hole covers and baffles.
Do check weather strip and hardware;
Don't live with poor performing components - replace them.