Repointing brickwork: when it is needed and how it is done
Part of our brickwork guides
Pointing is the sacrificial part of a wall. It is meant to weather and be renewed, protecting the bricks themselves. Repointed correctly it lasts decades; repointed with the wrong mortar it can do more damage than leaving it alone.
Signs the pointing has gone
Mortar that crumbles when you scrape it with a key, joints recessed well behind the brick face, sand collecting at the base of the wall, damp patches inside on an exposed elevation, or plant growth rooting in the joints. Isolated failures can be patched; whole elevations weathering back together need repointing as a run.
Why the mortar mix matters
Older London brickwork — Victorian and earlier stocks in particular — is soft and was built in lime mortar. Hard cement pointing traps moisture in the brick and forces it to escape through the brick face instead of the joint, which spalls the face off. Once a brick face has blown, pointing cannot bring it back.
The principle is that the mortar should always be weaker than the brick. On soft stocks that means a lime-based mix; on modern hard bricks a gauged cement mix is appropriate. Matching the existing mortar's colour, sand and joint profile is what makes a repoint disappear rather than announce itself.
How the work runs
Joints are raked out to a depth of roughly twice their width — deep enough for the new mortar to key, not so deep it undermines the brick. Grinders are used with care, or not at all on soft or narrow joints, because a slipped disc cuts brick arrises permanently. The wall is brushed and dampened, the mortar packed into the joint in layers, then finished to the original profile once it has taken up.
- Rake out to twice the joint width, by hand where the bricks are soft
- Brush out dust and damp down the joints
- Pack mortar firmly in layers so there are no voids
- Finish to match the existing profile — struck, flush, bucket handle or recessed
- Protect fresh work from direct sun, rain and frost while it cures
Frequently asked
How long does repointing last?
A correctly specified and properly packed repoint on a sheltered elevation can last several decades. Exposed elevations weather faster. Failures within a few years are almost always a mix or workmanship problem rather than the age of the wall.
Can you repoint in winter?
Not in frost. Mortar that freezes before it cures loses strength and fails. We work around forecasts and protect fresh work, but there are days when the right call is to stop.