Brick repointing:when mortar needs repair, and when filler will do

Brick repointing (also called pointing, and often called tuckpointing) means raking the old, failed mortar out of the joints between bricks and packing in fresh mortar. It restores the joint that keeps water out of the wall. Brick filler and caulk only cover the surface.

What brick repointing is

Mortar is the sacrificial part of a brick wall. It's meant to be softer and more porous than the brick, so movement and moisture work through the joints instead of the bricks. Over the years, rain, freeze-thaw cycles and the salts carried by water wear the joints back. Repointing replaces that worn layer before water gets behind it.

The job is simple to describe and slow to do well. The failed mortar is raked out to an even depth with square backs, the joints are brushed clean and dampened, new mortar is packed in thin layers, and the surface is tooled to match the original joint profile once it has firmed up. Done that way, with the right mortar, it lasts for decades.

Signs your brickwork needs repointing

• Joints recessed more than about a quarter inch behind the brick face.
• Mortar that crumbles to sand when you scrape it with a key or screwdriver.
• Cracks running along the joints, or stair-step cracks through several courses.
• White, powdery staining on the face of the wall.
• Damp patches, peeling paint or plaster on the inside of a brick wall.
• Bricks that rock when you push on them.

A stair-step crack, or a section that bulges or leans, can mean the wall or its footing is moving. That's a structural question to have looked at before any repointing.

Brick filler vs repointing: when filler is fine

"Brick filler" covers a range of products: acrylic and polymer fillers in caulk tubes, pre-mixed mortar repair compounds, and colored patching compounds for holes in brick faces. People reach for them because they're quick and need no mixing.

Filler is reasonable for:

• a small hole in a brick from an old bracket, cable clip or anchor
• a hairline gap in an otherwise solid joint
• a chip in an indoor or sheltered brick surface

Filler is the wrong fix for:

• joints that are sandy, recessed or missing over an area
• anything on a chimney, the top of a wall or a parapet, where water hits hardest
• steps and walls that get road salt, shovels and standing snow

The reason: a bead of filler sits on top of a shallow joint instead of filling it to depth, it doesn't bond to old mortar the way packed mortar does, and many flexible fillers hold moisture behind them. It looks fine for a season or two, then peels away and leaves the joint worse. Silicone and caulk also make proper repointing harder later, because every trace has to be cut out first.

Holes and damaged brick faces

If the face of a brick has flaked off (spalled), a colored patching compound can hide a small, shallow spot on a sheltered wall. On a deeply spalled brick, or several in a row, a patch won't last: the brick has failed and should be cut out and replaced. Spalling is often a symptom of the joints around it. When the mortar is harder than the brick, or water is trapped in the wall, the brick gives way first, so fix the cause or the new face will spall too.

Which mortar to use for brick repair

The rule: new mortar should match the old in color and texture and be no harder than the brick or the original mortar. Masonry mortars are graded from softer to harder as Type O, Type N, Type S and Type M (ASTM C270).

• Type N is the usual general-purpose mortar for above-ground brick walls, and the common choice for repointing houses built with modern cement mortar.
• Type S is stronger and is used where masonry is below grade, against soil or carrying more load, and for some steps and paving.
• Type O or a lime-rich mortar suits soft, older brick that was first laid in lime mortar, which describes many older homes around greater Boston.
• Type M is rarely right for repointing brick, because it's harder than most brick.

Bagged "mortar repair" mixes are generally fine for small jobs on modern brick if the color is close. On older brick, have the original mortar looked at before you choose. Brick steps get the hardest use of any brickwork, with salt, shovels and constant wetting, so their joints need full-depth repointing and tight tooling more than anywhere else.

Tuckpointing vs repointing

Strictly speaking, tuckpointing is a decorative finish. The joints are filled flush with mortar colored to match the brick, then a thin raised line of contrasting putty is "tucked" along the middle so the joints look narrow and crisp. Repointing just means replacing the mortar. In everyday use most contractors and homeowners say tuckpointing when they mean ordinary repointing, so when you're comparing quotes, ask what joint finish is included.

Can you repoint brick yourself?

A few feet of low garden wall, yes, with patience. The National Park Service's guidance on repointing masonry is the best free reference, and the basics are:

• Rake joints out to at least 2 to 2½ times their width, and past any loose mortar. Use a joint raker or plugging chisel; a grinder chips brick edges and widens joints.
• Brush out the dust and mist the joint so the brick doesn't pull water out of the new mortar too fast.
• Pack the mortar in thin layers of about a quarter inch, letting each firm up before the next.
• Tool the joint to match the old profile once the mortar is thumbprint-hard.
• Keep it damp and shaded for the first few days, and don't repoint when it's near freezing.

Hand it to a mason when the wall is high or on a chimney, when more than a small patch is failing, when bricks are loose or spalled, when the house is old enough to need lime mortar, or when there's an active leak inside.

What sets the cost of repointing

We won't give ranges here, because they'd mislead more than help. Repointing is mostly labor, so the cost follows the area of wall, how hard the old mortar is to remove, the joint width, access (ground level versus a chimney or a third-story wall that needs staging), how closely the color has to match, and whether bricks also need replacing. A good contractor should be able to show you which areas need repointing now and which can wait.

Chimneys, foundations and steps

Chimneys take the most weather of any brickwork and are often the first to need repointing. If yours also has a cracked crown or loose brick at the top, see chimney repair and rebuilds. Stone, brick and block foundations get repointed too, usually where joints have washed out near grade; that's covered under foundation repair. For walls, steps, veneer and general brick repair, see our masonry services.

Older brick around Woburn

Many homes in Woburn and the towns around it are old enough that their brick was laid in softer mortar, and every Massachusetts winter works on those joints. Water soaks into an open joint, freezes, expands and pushes it a little further open, and the next thaw lets more water in. Chimneys and front steps usually show it first, because they take the most weather: chimneys stand above the roof in wind and rain, and steps get snow, shovels and ice melt.

Dan in Arlington had us rebuild his brick and bluestone front stairs, and Cindy J. in Reading first hired us for a masonry repair; both reviews are below. You can see more of our work in the chimney projects and stairs and steps projects galleries, and our masonry services page covers brick repair, steps, walls and veneer. On any repointing job, we match the new mortar to the existing structure.

Who wrote this guide

Gerrior Masonry & Landscape Construction is a family-owned masonry contractor in Woburn, MA, repairing brick and stone around greater Boston for over 30 years. On our repointing work we match the new mortar to the existing structure, in color and in strength, so the repair blends in and moves with the wall. If you'd like a second opinion on your joints, the on-site estimate is free.