There’s a row of brick houses over near the Licking River where four of them were repointed together in the early 2000s, one contractor, one weekend rate. Three of those four now have brick faces popping off in coin-sized flakes along the lower courses. The fifth house in the row, the one that didn’t participate, is fine.
I get called to the three. And the conversation is always harder than people expect, because the damage isn’t in the joints they paid for.
What the brick around here is
Most of the nineteenth-century brick in this town was made close by, from river valley clay, fired in small batches. That gives you units of uneven color and size — you can see it on any unpainted wall in the old neighborhoods, the way the reds run from orange to near purple within one course.
It also gives you a soft, absorbent brick. That was fine, because it was laid in a lime mortar that was softer still, and the whole wall was designed to take on water and give it back.
The word that matters is sacrificial. The joint gives up material so the brick doesn’t have to. Repointing every sixty or eighty years was the maintenance cycle those buildings were designed around.
What hard mortar does to it
Put a modern Portland-based mortar into that wall and the ranking reverses. Now the joint is the strong part.
The wall still moves — it expands in July, contracts in January, and around here it does that through a lot of freeze-thaw cycles, more than the Deep South and fewer than Wisconsin, but with the wet winters that make every one of them count. Something has to yield, and it’s no longer the mortar. The brick spalls at the edges nearest the joint.
Water does the other half. With a dense joint, moisture that gets into the wall can’t leave through the mortar, so it leaves through the brick face, carrying dissolved salts. Those salts crystallize just under the fired surface and pop it off. That’s why the damage concentrates at the bottom of a wall — that’s where the water is.
How to tell before you hire anyone
Look at the relationship, not at either part alone.
- Perfect joints, crumbling brick edges — incompatible repointing, and it’s ongoing.
- Receding joints, sound brick — normal aging. This wall needs pointing and it’s in no danger.
- Scratch test. A key marks lime mortar without effort. If it skates off, that’s Portland.
- Color line. Modern repointing usually reads greyer and more uniform than the original, and you can often see exactly where the earlier work stopped.
What can be done about it now
Here’s the uncomfortable part: you can’t undo it cheaply. Cutting hard mortar back out of a soft wall risks more damage than leaving it, because the mortar is now stronger than the thing you’d be prying it away from.
What I recommend, in order of how much it helps per dollar:
Get the water off the wall. Gutters, downspouts discharging well away, grade falling away from the base, no sprinkler hitting the brick. On a wall already in trouble this slows the spalling more than anything else available.
Leave it uncoated. The instinct is to seal a spalling wall. A film-forming sealer traps the moisture that’s causing it, and you’ll take off more face in three years than you would have in fifteen.
Replace units selectively as they fail, in a compatible lime mortar, matching size and color as closely as salvage allows. $40 to $75 per brick.
When a whole elevation is due, redo it properly — cut out by hand, repoint in a matched lime mix at $25 to $45 per linear foot of joint. Expensive, and it ends the cycle instead of extending it. The distinction between that work and cosmetic tuckpointing is worth understanding before you buy either, and I’ve set it out in repointing and tuckpointing are not the same job.
If you’re getting bids, ask what mortar type they’d use and why, and whether they cut joints by hand or with a grinder. The technical notes from the Brick Industry Association cover mortar selection for older masonry, and a contractor who’s read them will answer in specifics rather than in reassurance.
Frequently asked questions
Why is my brick flaking off after repointing? Because the new mortar is harder than the brick. Movement and trapped moisture then damage the brick face instead of the joint. It’s the most common cause of spalling on nineteenth-century walls and it continues until the water is managed or the wall is properly repointed.
Can hard mortar be removed from old brick? Sometimes, by hand, at real risk to the brick — the mortar is now stronger than the units around it. It’s usually only worth doing as part of a full repointing of an elevation, not as a spot correction.
What mortar should be used on old soft brick? A lime-based mix softer than the brick, matched to the original by analysis where the building warrants it. The joint should always be the sacrificial element in the wall.