Repointing mortar

If old mortar has cracked or deteriorated, get advice from a structural engineer about whether it is a sign of a structural problem or simply due to settlement. If settlement is the cause, mortar can be repointed (shown here) or “stitched” (a technique involving special “stitching rods” and an epoxy resin). If the problem is more serious, follow your engineer’s advice on tackling it.

Tools and materials

Gloves, goggles, joint raker, club hammer, cold chisel, brush, misting spray, brick trowel, brick jointer, paintbrush

1. To prepare the wall, use a joint raker to remove any loose, crumbly bits of old mortar. Guard against flying debris and scrapes by wearing goggles and gloves.

2. Use a club hammer and cold chisel to “peck” out solid chunks of mortar from between the bricks. Then dust out the old mortar joints to remove all debris.

3. Use a spray to wet the bricks and mortar joints. This prevents the bricks from soaking up the new mortar and ensures that it will adhere.

4. Use a brick trowel and a brick jointer to press new mortar into place. Use the jointer to match the profile of existing mortar joints.

5. Use a dry paintbrush to remove any of the excess mortar and to tidy up the joints.

Shaping mortar

Joints are key components in masonry work. Not only do they hold the bricks in place, and keep the structure solid, but they also form part of the design, particularly in the case of brickwork. Garden wall joints, for example, can be pointed in various ways. The jointer creates a V-shaped profile, and a trowel can angle the mortar so that it is recessed at the top and flush with the brick at the bottom, to shed water.

How the joint raker works

A hardened masonry nail is positioned between two wheels on a cast aluminium frame. A simple wingnut mechanism adjusts the depth of the nail. The raker is then wheeled across the wall surface, with the wheels straddling a joint, allowing the nail to scrape out the old mortar. Wear gloves to protect your hands.

DIY Doctor, published by Dorling Kindersley (priced £9.99), provides quick-fix techniques for tackling the most common DIY problems. Presented with clear, straightforward instructions and step-by step photographs, this book shows readers exactly what to do and provides advice on the best tools and materials for the job.
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