Tuckpointing near you

A simple check tells you a lot: drag a key along a joint. Sound mortar resists, while mortar that crumbles into sand or comes out in chunks has done its job and needs renewing. Look over the whole wall, but pay extra attention to the places where water lingers.

In a healthy wall, the mortar is the sacrificial part. It should be slightly weaker and more porous than the brick around it, so that movement, moisture and salts work on the joints, which can be renewed, instead of on the bricks, which are much harder to replace. When the mortar is harder than the brick, the roles flip: stress and water are pushed into the brick edges, and the faces can crack or pop off along the new joints over the following winters.

That's why hard, cement-rich modern mortar can damage older brick. Many older Canadian houses were built with softer brick laid in lime mortar, and repointing them with a strong modern mix is a common way they get harmed. Newer, harder brick tolerates a stronger mortar, so the right mix depends on the wall. A careful mason judges the age and hardness of the brick and the existing mortar before choosing, and on historic buildings follows the conservation approach of the Standards and Guidelines for the Conservation of Historic Places in Canada.

Repointing changes how a wall looks more than most owners expect, because the joints make up a big part of the visible surface. Colour comes mostly from the sand and any pigment, and mortar dries to a different shade than it shows when wet. On a whole-wall job, ask for trial panels in a hidden spot and compare them, once cured, with a cleaned piece of the original mortar rather than the grimy surface. The shape of the joint matters just as much.

The old mortar is removed to an even depth, far enough to reach sound material and give the new mortar a good grip. Soft or historic brick calls for hand chisels, and grinders belong only in skilled hands, because a blade that wanders nicks the brick edges and widens the joints for good. The joints are then cleaned out and dampened so the brick doesn't pull water out of the fresh mortar too quickly.

New mortar goes in thin layers, each pressed firmly and left to stiffen before the next, and the final layer is tooled to the chosen profile once it reaches the right firmness. Grinding out mortar throws off fine dust containing crystalline silica, which CCOHS links to serious lung disease and lung cancer. Expect grinders fitted with dust extraction, respirators for the crew and closed windows and vents on that side of the house, and keep children and pets away. Work above the ground floor needs scaffolding or a lift and fall protection.

Fresh mortar needs moderate conditions to cure, so tuckpointing is seasonal work across most of Canada. The mortar has to stay damp enough to harden properly and must not freeze while it's still green.

Tuckpointing renews the joints; brick repair replaces the units. If the mortar is worn but the bricks are sound, repointing is the whole job. If some bricks are cracked, spalled or loose, they're replaced first and the joints around them repointed afterwards. If a section bulges, leans or has lost its ties to the house, neither is enough, and that part of the wall has to be rebuilt.

Either way, find out why the joints failed. Mortar worn away under a leaking sill, behind an overflowing gutter or at a wall base buried in soil will wear out again unless the water is dealt with. Stair-step cracks that keep growing point to movement below, and repointing over them only hides the evidence; the brick repair and foundation cracks pages cover what to check.

In Quebec, repointing is masonry work, so the contractor needs RBQ subclass 4.1 or 4.2, which you can confirm in the RBQ registry. Like-for-like repointing rarely needs a building permit, but on a designated property or in a heritage district, even a new mortar colour or joint style can need approval, and Quebec's classified properties need the Ministry of Culture's authorization before repairs. Ask your municipality before work starts.