By Jim Salmon
Cracked and missing mortar can lead to damp inside your home so try and deal with the problem before it becomes too serious. Here’s how to tackle small problem areas. You will need a pointing trowel with a 3-4in blade and a wooden handle for comfort. If the entire wall is affected, you may want to call in a professional.
Time to complete job: Repointing is a time-consuming job. A square yard patch of wall should take around four hours to rake out and repoint.
You will need: Club hammer, Narrow cold chisel, Bucket, Water spray, Mortar (ready-mixed pack), Carrying board, Pointing trowel, Stiff brush, Safety goggles, Thick gloves
Step 1: Preparation
Remove the old weathered mortar to a depth of about 12mm (0.5in) so that the new mortar will have enough brick area to form a good bond. Chip away any pieces of mortar stuck between the bricks with the cold chisel and club hammer. Old brickwork is usually very absorbent. Spray the bricks and mortar joints with a plant sprayer and cold water.
Tip: Always wear goggles and thick gloves when using a cold chisel.
Step 2: Applying the mortar
Mix up a small batch of mortar mix. A ready-mixed pack is ideal for small areas but it’s cheaper to use cement and sand for larger sections. Use a mix of one part cement to six parts builder’s sand and one part lime. Load some of the mix onto the carrying board and start to push mortar into the vertical joints with the pointing trowel. Next, force more mortar into the horizontal joints. Try to keep the mix away from the brick face to prevent it staining.
Tip: Keep the carrying board just underneath the joint to catch mortar that falls as you work.
Step 3: Shaping the mortar
Once the patch has been repointed, test the mortar to see if it is ready for shaping by pressing your thumb into the surface. If the mortar holds a clear print, it’s dry enough to be shaped. Try to match the existing pattern of pointing as much as possible. You can make the pointing flush with the brickwork with the edge of the trowel or a joint strike. Leave the mortar to harden for at least an hour, then brush off any debris from the face of the brickwork.
Tip: To make a concave shape to match old pointing, drag a piece of bent metal pipe along the joints – shape all the vertical joints first, then finish with the horizontal pointing.
