Leaky Sliding Door

House Doctor | Gary Dymski

October 19, 2000

Q. I live on the ground floor of a two-story condominium and there is a sliding-glass door on a part of the living-room wall. The door leads to a patio, which is beneath an upper balcony. The floor of this upper balcony permits some rain to come through the sliding glass door portion of the wall. I have lived here for 13 years, and this is my first problem.

I have been told that the outside of my condo belongs to the homeowners association and I cannot alter it in any way. The inside, however, belongs to me and I can do with it as I please.

I am an 85-year-old widow and would appreciate your advice.

-Rose Fasullo, Middle Island

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A. My first step would be to complain loudly to the homeowners association about the leak. I can't be sure, but I suspect there is a problem with the flashing on the exterior of the building, which, if you are correct, would seem to be the responsibility of the homeowners group that apparently maintains your condo.

If water is leaking through the sliding glass door, there likely is a problem with flashing, the sheet-metal material that is formed and fitted between exterior joints to prevent rain and moisture leaks.

There are several types of flashing for doors and windows, siding, roofs and eaves and extended porches. If these flashing systems wear out, leaks can occur. Why does flashing wear out? It's a thin piece of metal in most cases, held in place with nails and caulk. These materials can't stand up to the constant change in temperature and moisture. It's best to have flashing inspected in the fall, before the snow, and again in the spring, before the heavy rains come.

If these flashing systems aren't repaired, there will likely be water damage to interior walls.

You don't always have to have a professional opinion before determining if there is a flashing problem. You can make a visual inspection. Your first step should be to look at the exterior molding around your sliding glass door. There should be flashing on the top of the header, which is the piece of molding that runs along the top edge of the door. This flashing is shaped in the form of a Z and is kept in place with nails and caulk.

If that flashing appears OK, the next step would be to look at the balcony. I suspect that your building has some sort of siding, vinyl or wood, and perhaps a leak has developed between the pieces. Again, depending on the type of siding, a flashing system must be in place here, too. The more likely spot for a flashing breakdown appears to be the floor or roof of the balcony above your sliding glass door.

The design of the balcony aside, it still must have a flashing system to divert water from the openings of the building, doors, windows, chimneys and such.

On the balcony, look for cracks or openings along the eaves. Are any shingles cracked or broken? Is there any molding or siding material that appears to be pulling away from the joints?

Several types of flashing are used on eaves. Drip edge is used to prevent rainwater and ice from seeping back up under shingles along the edge of the roof. Rake flashing is used on gables, and step flashing-pieces of formed metal overlapped in steps - is common when a sloping roof intersects a vertical wall.

You write that one problem might be that your upstairs neighbor often waters plants on the balcony above your sliding glass door. I doubt that this is the cause of your leak-however, any water that is not diverted properly with flashing could be getting into your wall.

Urge a representative of your homeowners association to examine the exterior of the building. If you have trouble getting a response, show up at the association's next meeting and ask to be heard. I'll bet you'll get some sort of reaction to your complaint.

Depending on the location of the problem, it's likely a roofing contractor or a exterior door and window contractor will be able to make the necessary repairs.