Brick Repointing: How to Restore Crumbling Mortar Joints

TL;DR: Crumbling mortar lets water into a brick wall and eventually loosens the bricks. Repointing restores the joints — here's the right way.

_Last reviewed: July 2026 · 2 min read_

Mortar is the sacrificial part of a brick wall — it's meant to weather and be renewed, while the bricks last. When joints crumble, water gets in and eventually loosens the bricks, so repointing (replacing the surface mortar) protects the whole wall. Four steps: spot the bad joints, rake them out, match the mix, and tool them to match.

How do I know if brick needs repointing?

Look for crumbling, cracked, or recessed joints — mortar that's powdery, falling out, or set back from the brick face. You can often scratch failing mortar out with a key. Catch it early: once water gets deep into the joints and behind the bricks, you're looking at bigger masonry repair, not just repointing.

How deep do I rake out old mortar?

Rake out the old mortar to a consistent depth — generally about ¾ inch, or roughly twice the joint width — using a hand tool or a grinder with care. Consistent depth gives the new mortar enough to grip. Don't go so deep or aggressive that you chip the bricks; the goal is removing failed mortar, not the brick edges.

Why match the mortar mix?

Match the new mortar mix to the original — this matters more than people think. Old brick is often soft and needs a softer, lime-based mortar; using a hard modern Portland mix on soft brick traps moisture and can crack the bricks themselves. Match the type, and the color, so the repair blends and the wall stays sound.

How do I finish the joints?

Tool the new joints to match the existing profile (concave, flush, raked, etc.) once the mortar is thumbprint-firm. Matching the profile makes the repointing blend into the wall instead of standing out. A jointing tool gives the clean, water-shedding finish that also looks original.

Log the masonry work

Recording the mortar mix and repointing date helps with future matching. Okoniq Property Hub keeps it with your home maintenance records in one private place. Avoid blasting joints when pressure washing.

Frequently asked questions

Can I repoint brick myself?

Small areas at ground level, yes — with patience and the right mortar. Large areas, anything high up, or historic/soft brick is best left to an experienced mason to avoid damaging the bricks.

How often does brick need repointing?

Quality mortar joints can last 25–50+ years. Inspect periodically and repoint sections as they fail rather than waiting for widespread deterioration.

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FAQ

How much does brick repointing cost per square foot?

Expect $10 to $30 per square foot for professional repointing, depending on wall height, access difficulty, and whether mortar needs to be custom-matched for historic brick.

What happens if I use the wrong mortar mix for repointing?

Using a harder Portland-cement mortar on soft old brick traps moisture inside the wall and can cause the bricks themselves to crack or spall, creating more damage than the original failing mortar.

Can I repoint brick in cold weather?

Mortar shouldn't be applied when temperatures are below 40°F or expected to drop below freezing within 24 hours, as freezing prevents proper curing and weakens the bond.

How long does repointing mortar take to cure before it gets wet?

New mortar joints need at least 24 to 48 hours of dry conditions to cure enough to resist rain; cover the wall if weather threatens during that window.