Lining vertical stacks

What goes wrong in a stack

Most older apartment buildings, hotels and high-rises have cast iron stacks. Cast iron rusts from the inside. Over decades the wall thins, scale builds up and narrows the pipe, and cracks open, often along a seam or at a joint. The first signs are usually a stain or a leak on a ceiling or wall below a bathroom, a sewer smell in a unit, or drains on one stack backing up while the rest of the building is fine.

Why line it instead of replacing it

• Replacing a stack means opening the wall or chase on every floor it runs through, then patching and repainting each one.
• Lining works from inside the pipe, through an opening at the top or bottom of the stack, so the walls stay closed.
• People stay in their units. Only the fixtures on the stack being lined are out of use while the crew works and the liner cures.
• Each branch that joins the stack is reopened from inside after the liner cures.

What it can't fix

A stack with a section rusted through to a hole, or a joint that has come apart, may need that piece replaced before the rest can be lined. A camera run down the stack, with distances, shows which you have, and where.

Telling the residents

Every unit on the stack loses its sinks, tubs, showers and toilets for the time the work takes. Ask for the schedule, give notice in writing, and post it where everyone will see it. One flush during the cure can spoil the liner.

Who does the work

The company that answers this number lines vertical stacks as well as underground sewer lines, in hotels, high-rises, industrial and light commercial buildings, and homes.

What to ask

1. The camera video of the stack, top to bottom, with the bad spots marked.
2. Where the crew gets in, and whether any wall has to be opened.
3. How each branch will be reopened, and how the crew will know it found every one.
4. How long each unit's fixtures will be out of use.
5. The warranty, in writing.