Basement wall crack repair
A crack that leaks isn't always a structural problem, but it won't seal itself. The right repair depends on what the wall is made of and whether it's still moving.
Poured concrete shrinks as it cures, so thin vertical cracks are common in walls only a few years old. Block, brick and stone walls crack along their mortar joints, and that mortar softens and washes out over the decades. Water finds every one of those gaps. A good contractor starts by identifying the wall type, measuring the crack and asking whether it has changed.
Which cracks are more than a leak?
- A horizontal crack, or a wall that bows inward
- Stair-step cracking through block or brick joints
- A crack noticeably wider at one end
- Cracks that keep growing or reopen after patching
- New cracks in the floor slab at the same time
Those can point to soil pressure, settlement or, in the Johnstown area, ground movement over old mines. An engineer's look may be worth it before anyone seals the crack. A narrow vertical crack that just seeps is usually the simpler case.
How are cracks fixed?
- Injection in poured concrete. Ports are set along the crack and resin is pumped in until it fills the crack through the wall. Flexible polyurethane is mainly for stopping leaks; rigid epoxy bonds the concrete back together.
- Block walls. Leaking mortar joints can be repointed. Hollow cores that fill with water are often drained into an interior system.
- Stone and brick. Older walls may need repointing with mortar soft enough to match the original. Hard modern mortar can trap water and damage old masonry.
Will I need a permit?
The City of Johnstown says building permits are required for all repairs, renovations, remodels and new construction other than painting and flooring, so assume a city foundation repair needs one. Outside the city, ask your borough or township. Your contractor should tell you who is applying.
What drives the cost?
- How many cracks and how long they are
- Poured, block, brick or stone construction
- Finished walls, framing or ductwork in the way
- Any bracing or structural work the wall needs
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
Is hydraulic cement good enough for a leaking crack?
It can slow a small leak for a while, but it only covers the surface and water often works around it. Injection fills the crack through the wall's thickness.
Could my cracks be from mine subsidence?
It's possible in parts of Cambria County. Check DEP's mine subsidence map for your address, and if cracks are growing or the floor is moving, get them evaluated before waterproofing over them.
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.