Tuckpointing Mistakes That Cost Chicago Owners Twice

Tuckpointing mistakes are rarely visible on the day the scaffolding comes down. The wall looks clean and uniform. The cost shows up one to a few winters later, when joints open again or the brick itself begins to fail. Here are the mistakes behind that, why each one fails, and how to tell whether your wall has been done wrong.

What are the most common tuckpointing mistakes?

In rough order of how much damage they do:

1. Using mortar that is harder than the brick.
2. Not grinding the old joint out deep enough, or damaging the brick edges while doing it.
3. Mortar that does not match the original in color and texture.
4. Pointing in freezing or fast-drying conditions, or skipping the curing steps.
5. Dust control skipped.
6. Repointing without fixing the water source.

Mistake 1: mortar harder than the brick

This one ruins walls. The National Park Service says repointing mortar must be softer and more vapor-permeable than the brick, and no harder than the original mortar. It calls the idea that harder or stronger mortar is better a common error (NPS Preservation Brief 2). The Brick Industry Association agrees on the principle: repointing mortar should be similar to or weaker than the original, to avoid damage to the brick that cannot be repaired (BIA).

The NPS calls the joint the sacrificial element: the mortar should relieve stress in the wall, not the brick (NPS). The mechanism is simple. When mortar is less permeable than soft brick, moisture and dissolved salts leave through the brick instead. Salt crystallizing inside the brick can make the face spall or delaminate (NPS). We cover this one in full in the mortar mistake that ruins old brick.

Mistake 2: joints not ground out deep enough, or brick damaged doing it

Old mortar should be removed to a depth of 2 to 2.5 times the joint width. For most brick joints that is about 1/2 to 1 inch. Loose mortar deeper than that comes out too (NPS). A new joint that is only skimmed into the surface has nothing to hold on to. It pops out, usually the first time it freezes.

The tool matters too. The NPS says hand chisels are the traditional method, and power grinders belong only in skilled hands and only on horizontal joints, with care (NPS). A grinder run carelessly widens the joint and chews the brick edges. That damage does not go away when the new mortar goes in. See how deep to grind mortar joints.

Mistake 3: color and texture that do not match

Mortar color and look come mostly from the sand, which is the largest ingredient by volume. The NPS says to match sand color, gradation and texture to the historic mortar, plus tooling and joint profile, and to build a test panel (about 3 feet by 3 feet for brick) to set the standard of work (NPS). A job done without a test panel is a job the owner approves after the whole wall is done. See matching mortar color.

Mistake 4: wrong weather, no curing

Mortar needs wall temperatures between 40 and 95 degrees F to avoid freezing or drying out too fast. The NPS says not to use antifreeze admixtures, which can add salts that cause efflorescence later, and to warm the sand and water and protect finished work from freezing instead (NPS). Lime-rich mortar dried too quickly can chalk and lose adhesion. The NPS advises light misting once joints are thumbprint-hard and tooled, and covering walls with burlap for the first three days (NPS). For below-40 conditions the trade standard summarized by BIA has specific steps for protecting the work (BIA summary of cold weather masonry rules). See tuckpointing in winter.

Mistake 5: no dust control

Grinding out mortar throws silica dust. OSHA's silica standard requires a tuckpointing grinder with a shroud and dust collection, and respiratory protection for the crew (OSHA). A crew without that equipment is cutting corners that tend to show up elsewhere too.

Mistake 6: repointing without finding the water

If water is getting behind the wall, fresh joints are a short-term fix. BIA says to find and fix the moisture or salt cause before removal work (BIA). On Chicago buildings that often means looking at missing flashing, failed lintel flashing, and the top of the wall: caps and copings sit at the most exposed location and are there to channel water away (BIA guidance on flashing, caps and copings).

How can I tell if my tuckpointing was done wrong?

• Joints that are standing proud of the brick, or noticeably lighter, grayer or whiter than the brick.
• Brick faces flaking or popping off right beside the new joints.
• Joints that have fallen out again within a few seasons.
• Bricks with chewed or widened edges beside the joint.
• A color or texture patchwork, new joints that never blended.
• Efflorescence (white salts) returning after the job.
• No record of a permit for the work. The City lists tuckpointing as eligible Express masonry work, so there should be one (Express masonry page).

How is it fixed?

It depends on what failed. Joints that are only shallow or badly color-matched can often be ground out and redone with the right mortar. If the wrong mortar has already damaged the brick, the first step is removing the hard mortar carefully, without making the damage worse, and replacing the bricks that have lost their faces. Then the wall is repointed with a softer mortar suited to the brick, after the water source has been found. A masonry contractor should look at the wall before quoting, because the repair scope depends on how far the damage went.

What should I ask a contractor?

Ask what mortar they will use and why, how deep they grind and with what, whether they will do a test panel, how they handle dust, and what they will do if they find water getting into the wall. For help answering those, see our tuckpointing crew and the Chicago tuckpointing guide. Brick Industry Association guidance notes that the terms pointing, repointing and tuckpointing are used interchangeably (BIA), so make sure the quote spells out the scope.

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.