Plumbing in Semi-Detached Homes

Pipes we expect to find

Semis from the seventies and eighties mostly drain through ABS plastic, with copper supply or, in homes from roughly the mid-eighties to the mid-nineties, grey polybutylene. Newer semis in the north end use PEX with a manifold near the water heater. The two halves of the building are usually laid out back to back, so the kitchen and bathroom stacks run up near the shared wall.

Faults that bring us out

• Poly-B fittings cracking and leaking inside finished basement ceilings.
• Sump pumps failing in storms where the lot drains toward the house.
• Shower valves leaking into the wall shared with the main bathroom stack.
• Slow kitchen drains from grease built up in long horizontal runs.
• Water heater relief valves dripping as tanks reach the end of their life.

Jobs we do most in semis

Poly-B gets cut out and swapped for PEX or copper, swap tired sump pumps and add check valves, and open bathroom walls to change cartridges and pressure-balancing valves. Grease-heavy kitchen lines get snaked or jetted from the cleanout. See sump pump installation and shower valve replacement.

Living close to the neighbours

Your drain line and your neighbour's usually leave the house separately, but they can run close together out to the street. When both homes back up in the same storm, the cause may be the city sewer rather than either lateral. A backwater valve is the usual protection, and we fit them in semis regularly.