Exterior foundation waterproofing
Exterior waterproofing stops water at the outside face of the wall, before it ever gets into the foundation. It's the most disruptive option, and sometimes the right one.
Interior systems manage water after it comes through the wall. Exterior waterproofing keeps it out of the wall. The crew digs down along the outside of the foundation to the footing, cleans the wall, applies a waterproofing membrane or coating, adds drain board to relieve pressure, and lays a footing drain that carries water to daylight or a sump. Then the trench is backfilled and the grade restored.
When is exterior work the better choice?
- The wall itself is saturated and damaging finished space, not just leaking at the floor
- Water enters high on the wall, above where an interior drain would catch it
- You're already digging for other reasons, such as a new addition or a sewer lateral
- The foundation needs repair from outside, like repointing a stone wall or rebuilding a section of block
What does the job involve?
- Utility marking. Pennsylvania law requires anyone digging, homeowners and contractors alike, to call 811 at least three business days before starting so underground lines can be marked.
- Excavation. Usually by machine where there's room, by hand near porches, walks and tight lot lines common in older city neighborhoods.
- Wall prep and repair. Cleaning, patching and sometimes parging before the membrane goes on.
- Membrane and drain board. The membrane keeps water out; the board gives it a path down to the footing drain.
- Backfill and grading. Clean, free-draining fill near the wall and a finished grade that slopes away from the house.
Permits and neighbors
Excavating along a foundation may involve a building permit, and on narrow lots it can affect a neighbor's walk or yard. In Williamsport, the Bureau of Codes issues building permits; in South Williamsport, Montoursville and the townships, check with the municipal office. If your property is in a mapped floodplain, ask about floodplain rules before work starts.
What affects the price?
- Depth of the foundation and how much wall is exposed
- Access: decks, porches, driveways, landscaping and lot lines
- Condition of the wall once it's uncovered
- Where the footing drain can discharge
- Restoring lawn, walks or patios afterward
The waterproofing company sets the price, and it should do that only after someone has been in the basement, looked at the walls, floor joint and sump, and walked the outside of the house. We don't quote prices. A figure offered over the phone before anyone has seen the foundation is a rough guess, not a quote.
Where we connect you with help
Common questions
Can exterior waterproofing be done on just one wall?
Yes. If the water problem is limited to one side, such as the uphill side or a wall under a bad downspout, many companies will excavate only that section.
How long does exterior waterproofing take?
It depends on how much wall is involved, access and weather. Ask the company for a schedule in the written contract, which Pennsylvania law requires to include estimated start and completion dates.
Related services
More background: Lycoming County basement water guide.
Wet floor after every storm, or a sump that runs all night?
Call and a Lycoming County waterproofing company will set up a visit.