Repointing Brickwork: When It's Needed
Pointing is the mortar between bricks. It weathers over decades and eventually needs renewing, and doing it with the wrong material is one of the most common and damaging mistakes in building maintenance.
When it actually needs doing
Mortar that is receding significantly, crumbling to the touch, or missing in places. Small surface erosion is normal and not a reason to repoint.
Damp penetrating internally that traces to a specific area of failed pointing.
Loose bricks or movement, which usually indicates a problem beyond the pointing.
Whole-house repointing is frequently sold when only elevations facing prevailing weather need attention. Repointing sound mortar is unnecessary work that removes material from the joint edges.
Lime versus cement
This is the critical distinction. Older solid-wall buildings were built with lime mortar, which is softer than the brick and allows the wall to absorb and release moisture.
Cement mortar is harder than many older bricks. Water that would have evaporated through the joint is forced instead through the brick face, and freeze-thaw cycles then blow the brick surface off.
The result is a wall with intact pointing and eroded bricks, which is far more expensive to remedy than repointing would have been.
Modern cavity-walled houses built with cement mortar should generally be repointed with a compatible cement mix. Older solid-walled buildings need lime.
If in doubt about the age or construction, take advice before anyone starts, because reversing cement pointing on a soft brick wall is slow, expensive and damaging in itself.
Doing it properly
Old mortar should be raked out to a depth of at least two to three times the joint width, and to sound material.
Angle grinders are quick and widely used, and they routinely damage brick edges. Hand raking is slower and safer, particularly on soft bricks.
The new mortar should match the original in strength, composition and appearance. Joint profile matters too — a weather-struck or flush profile sheds water; a raised or ribbon profile traps it.
Timing and conditions
Lime mortar needs protection from frost while curing and should not be applied in freezing conditions or in strong direct sun that dries it too fast.
Spring and early autumn generally suit the work best.
Getting it quoted
Ask which elevations are being repointed and why. A contractor recommending the whole house should be able to justify each face.
Ask what mortar mix will be used and why that mix suits the building. A contractor who cannot answer this on an older property is the wrong contractor.
Ask how the old mortar will be removed, and ask to see previous work on a comparable building.
Access costs dominate on upper floors, so combining with other work is worthwhile where possible.
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