Rowhome Party-Wall Leaks: Causes and Fixes
Why water comes through the shared wall in Philadelphia rowhomes, what causes it and how it gets fixed.
In a rowhome, the party wall is shared with the house next door. Water showing up on it, often near the top floor ceiling or in the basement, is one of the most common leak complaints in Philadelphia.
Common causes
- Flashing where your roof meets the neighbor's roof or a parapet has cracked or pulled away.
- A neighbor's roof that's lower, higher or in worse shape and sends water toward the seam.
- Deteriorated mortar or a parapet cap letting water into the masonry.
- Plumbing in the house next door.
- Basement seepage along the shared foundation wall.
How it gets fixed
- Check both rooflines and the flashing along the party wall.
- Repair or replace the flashing and seal the seam.
- Talk with the neighbor if the problem is on their side.
- Once dry, repair the interior plaster or drywall.
Related: roof leak repair · water damage drywall repair
FAQ
Who's responsible for a party-wall leak?
It depends on where the water is getting in. If the source is on the neighbor's roof or property, it usually means working it out with them.
Can a party-wall leak cause mold?
Yes. Damp plaster or drywall that stays wet can grow mold, so repair it promptly once the leak is stopped.