Masonry Foundation Repair in Chicago: Brick and Stone Walls

Masonry foundation repair is the work of restoring a basement or crawl space wall built of brick, limestone or rubble stone: repointing the joints, replacing failed units, fixing the water that is causing the damage and, when a wall has moved, rebuilding it to an engineer's plan. Plenty of older Chicago two-flats, three-flats and greystones sit on walls like this, and most of the damage we see comes from water.

This article explains how those repairs go, what separates a mortar job from a structural one, and how permits work. It covers brick and stone foundations, not poured concrete.

What does a brick or stone foundation repair involve?

A foundation wall repair breaks into three questions, answered in this order:

1. Why is the wall failing? Usually water, sometimes movement, sometimes both.
2. Is it a joint problem, a unit problem or a structural problem?
3. What repair fits the answer?

The usual repairs:

• Repointing. Removing failed mortar and packing in new. NPS says to remove old mortar to a depth of 2 to 2.5 times the joint width, about 1/2 to 1 inch for most brick joints, and to use hand chisels or power grinders only in skilled hands and only on horizontal joints (NPS Preservation Brief 2). See what tuckpointing is.
• Replacing units. Cutting out and replacing bricks or stones that have crumbled or spalled. See how to replace spalled bricks.
• Rebuilding a section. Taking down and relaying part of a wall, typically from an engineer's or architect's plan.
• Fixing the water. Gutters, downspouts, grade and drainage, covered below.

Why old foundation walls fail

Basement walls are among the wettest places on a building. Water sits against them from the outside, and moisture and dissolved salts move through the wall. NPS says that when salts crystallize inside soft masonry, the face can spall or delaminate (NPS Preservation Brief 2).

Common signs:

• Crumbling mortar you can scrape out with a key.
• Brick or stone faces that flake or sand away.
• White powder on the wall. See efflorescence on brick.
• Damp patches, or a musty smell in the basement.
• Stair-step cracks in the joints. See stair step cracks.
• A wall that bows inward or leans. See bowing brick walls.

Chicago requires the exterior of a structure to be maintained in good repair and structurally sound, and masonry joints not kept weather resistant or water tight are on the City's list of unsafe conditions (City of Chicago, 14X-3-303). That is the exterior rule, but the same masonry fails the same way below grade.

Water first, then masonry

Repointing a wall that stays wet buys you a few seasons, not years. These are the water sources worth checking before any mortar is mixed:

• Grade. University of Minnesota Extension recommends sloping soil away from a foundation at least 1 inch per foot for at least 6 feet, because backfill often settles toward the house (UMN Extension).
• Downspouts. The same source says downspouts need extensions or splash blocks that discharge at least 4 feet from the wall (UMN Extension).
• Footing drainage. NRMCA recommends drain tile or pipes around the exterior footing and exterior side waterproofing for poured basements (NRMCA CIP 7). That guidance is about poured concrete, so what it means for an old masonry wall is a question for your engineer or mason.

Mortar for old foundation masonry

The mortar rule for old brick applies to foundations too. Repointing mortar should be softer and more vapor permeable than the masonry, and no harder than the original mortar. NPS lists the assumption that harder or stronger mortar is better as a common error, because a mortar stronger than the units causes cracking and spalling of the units themselves (NPS Preservation Brief 2).

Foundation stone and soft brick are not forgiving. If the wall has been coated in hard cement, ask your mason how it will come off without damaging what is under it. For the principle in detail, see the mortar mistake that ruins Chicago brick, and for stone walls above grade, see tuckpointing limestone on a greystone.

When it needs an engineer first

Some foundation conditions are not a mason's call. If you see a wall that bows or leans, a crack that has widened, a wall that has moved or sagged, or movement together with water, get an Illinois structural engineer or architect to find the cause before a repair is priced. We are not going to give you a severity rule here. Nobody can honestly do that without seeing the wall.

For a plan-based Chicago permit, the City requires plans from an Illinois-licensed architect or engineer, usually an architect or structural engineer (City of Chicago).

Do you need a permit?

Chicago has one small masonry exemption. Residential buildings up to four stories (and accessory buildings like garages) can replace up to 50 square feet of masonry in kind, meaning brick, stone or concrete, without a permit (City of Chicago). Whether a particular foundation repair fits that exemption is a question for the Department of Buildings, because a foundation wall carries load.

Beyond that:

• The City's Express Permit masonry page lists routine maintenance and repair such as tuckpointing, up to 50,000 square feet, replacing the outer wythe, replacing a lintel up to 6 feet and rebuilding a masonry parapet up to 2,500 square feet.
• Rebuilding all wythes of an exterior wall, or constructing new masonry, is not eligible for Express (City of Chicago).
• The permit needs a City-licensed mason contractor, unless an eligible owner acts as their own contractor (City of Chicago). The mason license covers work in stone, concrete, terra cotta (including clay brick) and structural tile, above or below ground (mason contractor license).

Confirm the current route with the Department of Buildings before you plan on any of this. For the rest of the permit picture, see the brick repair permit rules.

What to ask before you hire

1. What is causing the damage, and how will you confirm it?
2. Do I need an engineer or architect before the work is priced?
3. What mortar will you use, and why is it right for this brick or stone?
4. Who pulls the permit, and is the mason City-licensed?
5. What will you do about water at this wall?

For an overview of how the pieces fit, start with the Chicago brick and masonry guide. If you want someone to look at the wall, our masonry crew can start there.

Common questions

This article explains general rules and common situations in Chicago. It is not legal advice, and City rules change. For a specific property, check with the Chicago Department of Buildings or a licensed professional.