Brick masonry repair on a Long Island home

Mortar is designed to be the sacrificial part of a masonry wall. It is meant to be softer than the brick, so that when the wall moves, the mortar cracks instead of the brick. That means deteriorating mortar joints are normal and expected on any wall past a certain age. Deteriorating brick faces are not.

Knowing which one you are looking at determines whether you are spending a few thousand dollars or a great deal more.

What Repointing Actually Is

Repointing means cutting or grinding out the deteriorated mortar to a depth of roughly two to two and a half times the joint width, cleaning the joint, and packing in fresh mortar in layers, then tooling it to match the original profile. Done properly, a repointed wall lasts another 30 to 50 years.

Done improperly — smearing new mortar over the surface of old failing joints without cutting anything out — it lasts about two winters and looks bad the whole time. That surface smear is the most common bad masonry repair on Long Island, and it is easy to spot because the joints look raised and sloppy rather than crisp and recessed.

The Mortar Mix Problem

This is the part that quietly destroys older buildings, and most homeowners have never heard of it.

Modern Portland cement mortars are hard and strong. Older brick — particularly soft, low-fired brick common in pre-1930s Long Island construction — is comparatively soft and porous. If you repoint soft historic brick with a hard modern mortar, you invert the relationship the wall depends on. The mortar is now stronger than the brick. When the wall moves or when trapped moisture freezes, the mortar does not yield, so the brick face does. It spalls, flaking off in sheets.

You cannot undo that. Spalled brick has to be replaced, and matching salvaged brick is expensive and often impossible. A mason working on older brick should be talking to you about a softer lime-based mortar mix appropriate to the substrate. If they say all mortar is the same, walk away.

What It Costs on Long Island

  • Repointing: roughly $12–25 per square foot of wall face, higher for historic lime mortar work and difficult access
  • Spot repointing of a limited area: often a $1,200–3,000 minimum, since setup and staging dominate small jobs
  • Brick replacement: roughly $25–60 per brick for individual cut-and-replace work
  • Rebuilding a section of wall: roughly $40–90 per square foot
  • Chimney repointing: typically $1,500–5,000 depending on height and access
  • Stoop or step rebuild: typically $5,000–15,000

Repair or Rebuild? How to Tell

Repointing is usually enough when: mortar is receding, crumbling or can be raked out with a key, but the brick faces are intact; cracks are hairline and follow the mortar joints; there is no bulging or displacement; the wall is plumb.

You are probably looking at rebuilding when: the wall bulges outward or is visibly out of plumb; cracks run through the brick faces rather than around them; brick faces are spalling and flaking across an area rather than in isolated spots; you can see daylight or feel movement; or a stair-step crack has opened wide enough to indicate real structural movement or foundation settlement.

Stair-step cracking through the mortar joints is worth a specific note. A fine stair-step crack is often just seasonal movement. A wide one, especially one that is wider at the top or bottom, can indicate the foundation is moving. Repointing that crack without diagnosing the cause just hides the symptom until it reopens.

Long Island Specifics

Freeze-thaw drives most of the damage. Open joints let water in, water freezes, the joint opens further. This is why a small repointing job deferred for five years becomes a much larger job.

Salt air near the shore accelerates deterioration on South Shore and East End properties and is a factor in mix selection.

Chimneys take the worst of it. They are exposed on all four sides, they are the highest point on the house, and they get no shelter. On most Long Island homes the chimney needs attention well before the walls do. Water entering a deteriorated chimney crown travels down inside the structure and shows up as ceiling stains that get misdiagnosed as roof leaks.

Do Not Seal Your Way Out of It

Homeowners sometimes apply a waterproof coating to a wall with failing joints, hoping to stop water entry. On masonry this frequently makes things worse. Brick walls need to breathe — moisture that gets in has to be able to get out. A film-forming sealer traps that moisture inside the wall, where it freezes and spalls the brick from behind. Fix the joints. Do not paint over the problem.

Frequently Asked Questions

How often does brick need repointing?
Typically every 25 to 50 years depending on exposure, original mortar quality and how much weather that elevation takes. South and west facing walls and chimneys usually need it first.

Can I repoint brick myself?
Small, low, non-structural areas are a realistic DIY project if you cut the joints properly and match the mortar. The two ways it goes wrong are inadequate joint preparation and the wrong mortar mix, and the second one damages the brick permanently.

Why is my brick flaking and crumbling?
That is spalling, usually caused by trapped moisture freezing inside the brick. Common causes are repointing with too hard a mortar, a film-forming sealer applied to the face, or persistent water entry from a failed chimney crown, cap or flashing.

Does repointing stop water leaks?
Often yes, when the leak is coming through open joints. But water can also enter through failed flashing, a cracked chimney crown or a roof detail, so the source should be diagnosed before repointing is assumed to be the fix.

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