Interior basement drainage systems
If water keeps showing up at the base of the walls, an interior drain catches it before it can spread and sends it to a pump.
An interior drainage system runs around the inside edge of the basement, under the floor. The installer breaks out a strip of slab beside the walls, digs a shallow trench, sets perforated pipe in washed stone, and slopes it to a sump pit. Water pushing through the wall or rising at the floor joint drops into the pipe and is pumped outside. The trench is then filled with fresh concrete, and you get your floor back.
Is interior drainage right for my house?
It's often the practical choice in Johnstown's older neighborhoods. Stone and brick foundations can't really be sealed from the inside, and rowhouses or closely built homes may leave no room to dig outside. An interior drain doesn't keep the wall itself dry, but it manages the water once it arrives, without tearing up porches, driveways or a neighbor's side yard. It also works under newer poured or block walls when seepage shows up on several sides.
How does the installation go?
- Diagnosis. The company maps where water enters and checks the walls for cracks, bulges or loose mortar.
- Making room. Shelves, stored items and sometimes finished wall panels near the perimeter are moved out of the way.
- Trench and pipe. The slab is cut, the pipe is laid in stone, and many systems add a wall membrane so seepage runs down behind it into the drain.
- Pit and pump. A lined sump pit collects the water, and a pump pushes it out through a discharge line.
- Patching. New concrete goes over the trench.
Questions worth asking
- Which walls get the drain, and why not the others?
- How is the pipe protected from silt and iron sludge clogging it over time?
- Where will the pump discharge, and is that allowed where you live?
- Does your municipality require a permit, and who applies?
- What does the warranty cover, and does it transfer to a buyer?
What drives the cost?
- Linear feet of wall that need drainage
- Slab thickness and how easily the crew can get equipment in
- Finished walls, flooring or built-ins that must come out
- Choice of pump, backup system and discharge route
We don't quote prices. The waterproofing company prices the job after it has looked at the walls, the floor joint, the sump pit and the outside drainage, because the same symptom can need very different fixes. Treat any firm number given over the phone, sight unseen, with caution.
Where we connect you with help
Common questions
Does an interior drain make the walls dry?
No. It collects water after it gets through or under the wall. A membrane on the wall can steer that water into the drain so the floor stays dry.
Can I get an interior drain in a finished basement?
Yes, though the bottom of finished walls usually has to be opened up and rebuilt. Make sure the quote spells out who handles that and how.
Related services
More background: Johnstown basement water guide.
Wet floor after a storm, a crack that weeps, or a sump that never rests?
Call and we'll put you in touch with a waterproofing company that works in the Johnstown area.