Brick pointing: the right technique for long-lasting restoration

Is the brick veneer of your home in poor shape? Has the mortar in the joints disappeared, or is it wearing thin in some places? Worse yet, are some bricks loose enough to move around? Don’t delay! You’ve got to save your walls and look into brick pointing!

Brick repointing is required to avoid water infiltration or premature deterioration of the veneer that can even lead to collapse. As with any type of repair, repointing your brickwork will be long-lasting only if the appropriate material is applied by expert hands experienced in trade practices and during pleasant weather.

Steps in restauration

Preparation

As a general rule, the pointing to be repaired must be dug out to a minimum depth of about two-and-a-half times its thickness, in other words ¾ inch to one inch for regular 3/8-inch pointing. You need to dig at least ¾ inch deep for thinner pointing.

Weak mortarA mixture of cement, lime, and sand used for laying bricks or masonry. must be removed completely, leaving a vertical surface at the end of the cavity. Using an electric grinder creates less risk of damaging the brick. A single cut should be made in the centre of the pointing using a 1/8-inch thick disc, with the removal completed manually with a hammer and chisel. Be careful with percussive tools, which can weaken the brickwork. These tools should be used with the greatest care and only by experienced workers.

If the mortarA mixture of cement, lime, and sand used for laying bricks or masonry. turns out to be decayed over more than half its depth, it is preferable to dislodge the bricks and reinstall them on a new bed.

During digging, any particle that is dislodged must be removed completely using a brush or a low-intensity water or air jet.

Mortar

It is preferable to select a mortarA mixture of cement, lime, and sand used for laying bricks or masonry. that is specially formulated for repointing (one part Portland cement and two parts lime for every eight or nine parts sand). Compared to normal bedding mortarA mixture of cement, lime, and sand used for laying bricks or masonry., it provides increased waterproofing, excellent moisture permeability and great flexibility. Premixed and sold in bags, it offers the advantage of a uniform mixture of all ingredients, batch after batch.

In addition, mixing it requires little water. This is an important characteristic, since a drier mortarA mixture of cement, lime, and sand used for laying bricks or masonry. is easier to compact for pointing, less likely to tarnish the brick and less likely to shrink while drying.

It may be coloured in the factory or on site, helping harmonize it with the existing mortarA mixture of cement, lime, and sand used for laying bricks or masonry., especially when the repointing covers only a portion of a wall.

It is important to let the contractor know if a brick wall to be repointed was coated with a waterproofing product, which could compromise the adhesion of the mortarA mixture of cement, lime, and sand used for laying bricks or masonry..

Pointing

The surfaces to be pointed (existing bricks and mortarA mixture of cement, lime, and sand used for laying bricks or masonry.) must first be moistened to minimize loss of water in the mortarA mixture of cement, lime, and sand used for laying bricks or masonry. through sponge effect. Next, the mortarA mixture of cement, lime, and sand used for laying bricks or masonry. must be pushed to the end of the cavity and firmly compressed, in fairly thin layers applied right after the previous layer hardens but before it dries.

The surface of the mortarA mixture of cement, lime, and sand used for laying bricks or masonry. must be set when doing the finishing, in other words, when profiling the pointing (giving it a concave, V-shaped, oblique or other form of jointDevice or product for sealing a surface composed of several elements (brickwork).).

Weather conditions and drying

The temperature of the surfaces and the mortarA mixture of cement, lime, and sand used for laying bricks or masonry. should ideally remain between 5°C and 30°C for at least 72 hours. In the winter, protective matting is more or less essential to keep the mortarA mixture of cement, lime, and sand used for laying bricks or masonry. from freezing in the hours after it is applied. If it freezes, it would lose the properties that ensure the quality and durability of the work.

In very warm weather (25°C or higher), shrinkage cracks caused by excessively fast drying can be prevented by repointing only the shaded side of a building or by shielding fresh pointing from the sun. It should also be protected from the wind and rain.

Since repointing mortarA mixture of cement, lime, and sand used for laying bricks or masonry. is formulated to cause less mess, cleaning the surfaces should be fairly easy, but it requires four steps:

  • wetting the wall;
  • applying a detergent with a low acid concentration;
  • rubbing with a hard non-metallic brush;
  • rinsing.

CAADoing the last step manually is not as hard on fresh repointing as using a water jet.

A 48- to-72-hour period of good weather should precede the cleaning.