Foundation cracks and a wet basement: masonry repair, drainage or both?

Updated November 11, 2026 · KeystoneProGuide editorial team

Why do foundation walls crack and leak?

Mostly because of water and movement. Penn State Extension says stormwater can cause cracks in foundations and water damage around windows and doors, and that flooded basements are among the common and expensive results of heavy storms. The National Park Service (NPS) lists the causes of cracking in masonry walls generally, starting with differential settlement of foundations and including drying shrinkage, thermal and moisture movement, freeze-thaw cycles, rusting steel and expanding salts.

So before deciding what to repair, it helps to know which of those you are looking at.

What do the cracks tell you?

• Thin cracks along the mortar joints, especially in a stair-step pattern, are the kind the NPS associates with a wall that is probably moving with heat and moisture.
• Cracks through the blocks or bricks themselves are more often structural, the NPS says. In foundations, settlement is the first cause it names.
• A wall that bows inward or leans has moved, and the NPS warns that moisture damage left alone can leave a wall unable to carry its load.
• A crack that changes. The NPS advises watching a crack over time to see whether it is active; an active crack is sealed with a flexible material, an inactive one can be pointed.

A dated pencil mark at each end of a crack, checked every few months, is a simple way to see whether it is growing.

What is the damp line on my basement wall?

If the lower part of a stone or brick basement wall is damp up to a fairly even line, often with white salts along it, the NPS calls this rising damp: moisture wicking up from the ground by capillary action. It says the tide line often sits 3 to 4 feet above the basement floor. Over time the moisture breaks down the masonry, causing chipping and disintegration. Its warning about coatings applies here too: an impervious coating on the base of a wall can push the moisture higher and hide the damage.

What should you do first?

Start outside. Both FEMA and Penn State Extension begin with the water around the house.

• Downspouts. Penn State Extension says all downspouts should be directed away from foundations to avoid basement flooding, and suggests sending them to lawn or garden areas where possible.
• Grading. The Federal Emergency Management Agency (FEMA) advises adding fill with a binding material such as clay around the foundation and angling it away from the house.
• Openings. FEMA advises using mortar and masonry caulk to fill foundation cracks and to seal places where pipes, wires and cables pass through the wall.
• Pumps. FEMA describes sump pumps for basements that flood regularly or where the water table sits above the foundation, with a battery backup for power cuts.

Penn State Extension adds that complicated stormwater problems are worth an engineer's or landscape professional's opinion. FEMA also notes that a standard homeowners' policy does not cover flood damage.

What can a mason fix?

The masonry itself. A mason can repoint failed joints in a stone or brick foundation, replace deteriorated units, and rebuild a damaged section. HomeGuide prices repointing a stone foundation at $5 to $28 per square foot and a whole stone foundation at $3,500 to $10,000, and gives $250 to $800 per crack for foundation crack repair, a range Angi matches.

The NPS's principles for old walls still apply below ground: mortar should match the old in strength and composition, and hard, impervious coatings are never recommended for historic masonry. For concrete foundations, the General Services Administration's repair specification for historic concrete warns that patching compound should not be used to bridge cracks that are still moving; those are sealed with a flexible material instead.

What masonry repair cannot do is stop the cause. The NPS says structural repairs come before cosmetic ones. A crack from settlement, a bowing wall or water pouring in from a downspout will come back after repointing if the cause is not dealt with.

When is it more than a masonry job?

When the wall has moved or keeps moving. Signs such as bowing, leaning, or cracks through the units that keep widening call for a structural assessment before the repair is designed. Angi's foundation repair page gives a national average of $5,175 and suggests budgeting $500 to $3,000 for a soil report where the soil is in question. Work that cuts away part of a load-bearing wall or removes a beam or other load-bearing support is, under the state code, not an ordinary repair, and needs a permit.

What about digging outside the foundation?

Exterior waterproofing, drains and regrading all involve excavation next to the house. Pennsylvania 811 warns that buried lines can run along property lines and between lots, and it says the contractor doing the digging must notify it before work begins, and you should ask to see the eleven-digit PA One Call serial number.

For other signs that masonry needs attention, see warning signs. Before hiring, questions to ask covers cause, method and price. Masons are listed on the masonry contractors page.

Sources

1. Common Problems with Brick Masonry, U.S. National Park Service
2. This Masonry is for the Bees!, U.S. National Park Service
3. Is Stormwater Damaging My Property?, Penn State Extension
4. How Can I Control Stormwater on My Property?, Penn State Extension
5. Fact Sheet: Be Flood Smart. Protect Your Property, Federal Emergency Management Agency
6. Installation of concrete patching compounds, U.S. General Services Administration
7. How Much Does Foundation Repair Cost? [2026 Data], Angi
8. How Much Does Masonry Work and Brick Repair Cost? (2026), HomeGuide
9. How Much Does Tuckpointing or Repointing Cost? (2026), HomeGuide
10. 34 Pa. Code § 403.62. Permit requirements and exemptions., Commonwealth of Pennsylvania (Pennsylvania Code)
11. FAQs Homeowners, Pennsylvania One Call System (Pennsylvania 811)