How to Repoint Old Brick: A Complete Step-by-Step Guide

Most homeowners look at crumbling mortar joints and assume they need a mason, a scaffold, and a four-figure invoice. I’ll be honest: that assumption costs people real money every single year, because the vast majority of repointing jobs on a single-story home or a ground-floor foundation wall are well within DIY range if you understand what you’re actually doing.

What surprised me when I first got into this properly (and I mean beyond just slapping new mortar into old joints, which is a mistake I’ll come back to) was how much the prep work matters relative to everything else. The mixing, the actual trowel work, none of that is the hard part. The hard part is removing the old mortar correctly and matching your mortar type to the age of the brick. Get those two things wrong and you’ve made an expensive problem worse.

Why Old Mortar Fails (And Why It Matters Before You Buy Anything)

Old brick mortar is almost always a softer lime-based mix, especially on anything built before the 1930s. Modern Portland cement mortars are significantly harder than the brick itself. This is a real issue, not just historical trivia: when you repoint old soft brick with a too-hard mortar, the rigid new joints force stress into the brick face during freeze-thaw cycles, and you end up with spalling brick instead of just worn joints. I’ve seen this exact damage on a 1908 Craftsman bungalow in Milwaukee where a previous owner had repointed with standard Type S mortar. The original brick cost over $4,000 to replace. The repointing job probably cost $600.

The American Society for Testing and Materials classifies mortar into types M, S, N, O, and K, roughly from hardest to softest. For most residential repointing of pre-1950s brick, you’re looking at Type N (a 1:1:6 ratio of Portland cement, lime, and sand) or even a straight lime putty mortar with no Portland at all. Post-1950s brick can generally handle Type S. If you’re not sure what era your brick is from, go with Type N. It’s the safer choice.

And color matching: this genuinely takes some effort. Hardware store mortar pigment kits from Quikrete or Custom Building Products work, but you’ll want to test on a scrap piece of wood, let it cure for 72 hours (not just dry), and compare in natural light. The wet color lies. I’ve been burned by that more than once.

What You’ll Actually Need (With Real Numbers)

Before we get to the steps, here’s what the job costs, because I find vague ranges useless.

A typical 10x10 section of wall might run you $80-$120 in materials if you’re buying tools for the first time. If you already own the grinder, you’re under $50. Compare that to a mason charging $8-$15 per square foot for labor alone (current rates as of July 2026 in most mid-size U.S. cities), and you can see why this is worth learning.

Step-by-Step: How to Actually Do This

Step 1: Assess the scope. Walk the wall in decent light, ideally with a headlamp, and probe joints with a screwdriver. Soft, crumbly mortar that comes out without much pressure needs to go. Solid joints that resist probing? Leave them alone. You’re repointing compromised areas, not refinishing the entire wall for aesthetics.

Step 2: Remove the old mortar to depth. This is where most DIYers undercut themselves. You need to go back at least 3/4 inch, and 1 inch is better. Any shallower and the new mortar won’t bond well and will pop out within a few freeze-thaw cycles. An angle grinder with a mortar raking blade (Bosch makes a good one) handles horizontal joints quickly. Vertical joints are trickier with a grinder; a hammer and cold chisel is safer for staying on course. Work carefully near the brick edges. A slip that chips the brick face is visible forever.

A reader named David from Pittsburgh emailed me last fall about this exact issue: he’d used only a chisel on a 12-foot section, it took him an entire weekend, and he was ready to quit. When he rented an angle grinder for the horizontal joints on the next section, he finished twice the area in three hours. Use the right tool.

Step 3: Clean the joint. Blow out debris with compressed air or use a stiff (not wire) brush. Then dampen the joint with water using a spray bottle. This is not optional. Dry masonry sucks moisture out of fresh mortar too fast, killing the cure and weakening the bond significantly. Dampen, don’t soak.

Step 4: Mix your mortar. For most jobs, aim for peanut butter consistency, maybe slightly stiffer. It should hold its shape when you roll a small ball in your palm without cracking or slumping. If it’s too wet it’ll slump out of the joint; too dry and it won’t compact properly. Mix small batches (maybe 1/3 of a bag at a time) so you’re not watching it dry out while you work.

Step 5: Pack the joint. Load your hawk (or a scrap of plywood works fine), take a small amount on your margin trowel, and pack it firmly into the joint in layers if it’s deep. Don’t try to fill a 1-inch-deep joint in one pass; two layers of about 1/2 inch each is better practice. Press firmly so there are no voids behind the mortar face.

Step 6: Tool the joint. Let the mortar firm up until it holds a thumbprint but still dents (typically 20-60 minutes depending on temperature and humidity). Then tool the joint to match the original profile. Most brick uses a struck, weathered, or concave joint. A piece of 3/8" copper pipe curved into a slight arc is a perfectly serviceable jointing tool for concave profiles and it’ll cost you nothing if you raid your scrap bin.

Step 7: Clean and cure. Once the mortar is thumbprint-firm, brush off excess with a dry stiff-bristle brush. Don’t use water at this stage; it smears mortar into the brick face and is a nightmare to remove. After 24 hours, lightly mist the finished joints for two to three days to slow the cure and improve final strength. Avoid direct sun on fresh joints if you can time your work; hot, dry days accelerate surface curing while the interior stays soft, which causes cracking.

When to Stop and Call a Mason

I want to be straight with you about this part, because some situations genuinely need a professional.

Anywhere you’ve got active water infiltration behind the wall (bubbling paint on interior walls, efflorescence patterns suggesting hydrostatic pressure, or areas near grade where soil is against the brick) needs a diagnostic before you repoint. Repointing over active moisture intrusion just traps the water differently. It doesn’t fix the problem.

Structural cracks, meaning diagonal stair-step cracks through the mortar that are wider than about 1/4 inch, or any horizontal cracks in a load-bearing wall, are a structural engineer question, not a repointing question. I’ve seen homeowners repoint over foundation movement cracks three times in a row before finally calling an engineer who found a drainage issue causing lateral pressure on the foundation wall. The total repair bill was around $18,000 by that point. The engineering consult up front would have run $350-$600.

High work (anything above 8 feet without solid scaffolding) is also where I tell people to reconsider. I don’t mean a ladder for a small chimney flashing joint. I mean renting proper scaffold or hiring someone to handle second-story or gable walls. Falls from ladders are the leading cause of construction fatalities. That’s not fear-mongering; it’s the BLS data every single year.

Worked Examples

Front stoop, 1940s brick, 8 linear feet of deteriorated horizontal joints at grade level. → Homeowner ground out joints to 1 inch depth, used Type N mortar with tan pigment, finished in one Saturday. → New joints solid after one winter; matched original color within one shade.

Two-story chimney on a 1912 house in Cleveland. → Homeowner attempted DIY off a 24-foot extension ladder with moderate wind. Fell, broke wrist, damaged chimney cap. Total cost: roughly $11,000 in medical and repairs. → Same job with a mason and scaffold would have run about $1,400.

Basement foundation wall, 180 linear feet of joints, 1950s construction. → Owner rented a rotary hammer with a chisel attachment for $65/day, completed removal in two days, mixed Type S mortar in small batches over a week of evenings. → Total material cost: $310. Mason quote had been $2,800-$3,200.

Sources

• American Society for Testing and Materials (ASTM C270): Standard specification for mortar for unit masonry, defining mortar types M, S, N, O, K and their applications.
• National Park Service Preservation Brief #2 (Repointing Mortar Joints in Historic Masonry Buildings): Detailed guidance on mortar analysis, joint preparation, and matching historic mortars; particularly relevant for pre-1940 construction.
• Brick Industry Association Technical Notes on Brick Construction (BIA TN 7): Covers mortar selection, mix ratios, and installation practice for residential masonry.
• Bureau of Labor Statistics (BLS), Fatal Occupational Injuries Summary: Annual data confirming falls as the leading cause of construction fatalities; relevant for scaffolding and ladder safety decisions.
• Quikrete Mortar Mix Product Data Sheet (current formulation): Specification data on Type N and Type S premixed mortars, curing times, and coverage rates referenced in this article.

Photo: Vidul Arora via Pexels