Interior perimeter drains in Lancaster, PA
When water keeps showing up where the wall meets the floor, a drain along the inside of the foundation gives it somewhere to go.
An interior perimeter drain is a channel set into the basement floor along the foundation walls. The floor is cut open at the edge, a trench is dug, and a perforated pipe or channel is laid in clean stone, then the floor is patched back. Water that seeps through the wall or rises under the slab drains into it and runs to a sump pit, where a pump lifts it outside. For Lancaster County homeowners whose basements get a wet band at the floor edge every heavy rain, it's often the most practical way to keep the floor dry without digging up the yard.
Signs you may need one
- Water along the base of more than one wall after storms
- Seepage that comes up through the floor near the walls
- Damp spots that return no matter how often you patch
- Plans to finish the basement in a house with a history of water
- A stone or block wall that weeps at many points
Why does water collect at the floor edge?
Water in the soil follows gravity down the outside of the foundation to the footing, and the joint between the wall and the floor is the easiest way in. In much of Lancaster County, limestone-derived soils with clay-rich subsoils slow that water down, so it lingers. Older houses rarely have a working footing drain outside, and many farmhouse cellars were built with no floor slab at all, so there is nothing to catch the water before it spreads.
How do the systems differ?
- Pipe in stone below the slab. A perforated pipe in a gravel bed beside the footing, covered with new concrete. It's the most common approach in poured and block basements.
- Channel systems at the floor edge. Shallower channels that sit at the wall-floor joint, sometimes used where the footing is shallow or irregular, as in many stone cellars.
- Wall membranes. A dimpled plastic sheet on the inside of the wall can guide seepage down into the drain, though on stone walls it should not trap moisture against masonry that needs repair.
- Cleanouts. Access ports let the drain be flushed if silt builds up, which matters in fine, silty soils.
Every interior drain needs a sump pump system to empty it, and the discharge needs a plan. In limestone country that means spreading the water out rather than dumping it in one spot, for the reasons in our wet basement guide.
What affects the price?
- Length of wall to be drained, and whether it's every wall or just one or two
- Floor thickness, or no floor at all, and how much old patching is in the way
- Footing depth and condition, especially in stone cellars
- Number of sump pits and pumps, plus any backup
- Furnace, water heater, stairs and finished walls that must be worked around
The waterproofing company sets the price after an inspection. We don't quote jobs.
Where we connect you with help
Common questions
Does an interior drain stop water from coming through the wall?
No. It catches the water at the bottom and carries it away before it spreads across the floor. If the wall itself is wet or crumbling, it may also need masonry repair or a membrane.
How long does an interior drain installation take?
It varies with the size of the basement and access, but many jobs take a few days. The company you're connected with will give you a schedule.
Can an interior drain go in a cellar with a dirt floor?
Often, yes. Some companies will set the drain and then pour a new floor or lay a heavy vapor barrier over the dirt so the drain and the cellar stay cleaner.
Related services
- Stone foundation repair
- Sump pump systems
- Exterior excavation waterproofing
- Basement moisture and mold control
Background on soils, sinkholes and Pennsylvania contract rules: Lancaster County wet basement guide.
Stone walls weeping, a wet floor edge, or a pump that never rests?
Call and a Lancaster County waterproofing company will come find where the water gets in.