Repointing
Chimneys, gables and elevations raked out and pointed in the right mix.
In short
Pointing is the mortar in the joints between stones or bricks, and it is meant to be sacrificial: it weathers so the masonry does not. Once it has eroded back, water sits in the open joint and gets into the wall. Repointing means raking the failed mortar out to a proper depth and filling the joint with a mix suited to the masonry, which on traditional Scottish stone usually means lime rather than hard cement.
The mix matters more than almost anything else. A hard cement pointing on soft sandstone forces moisture to escape through the stone instead of the joint, and the face of the stone spalls off. It is a very common and very expensive mistake on Glasgow tenements and Ayrshire stone property.
Signs a wall or stack needs repointing
- Joints eroded back so the stone or brick stands proud
- Mortar that crumbles away when you rub it
- Damp on an internal wall with no other obvious source
- Vegetation or moss growing out of the joints
- Spalling stone faces, often a sign of previous cement pointing
- Previous repointing that has cracked or is falling out
What the job involves
Every roof is different, but the shape of the work is usually the same. Here is how a typical repointing job runs.
Work out the right mix
The masonry decides the mortar. Traditional stone generally needs a lime mix that stays softer than the stone around it.
Rake out properly
Failed mortar is raked out to a depth that lets the new pointing key in, rather than being skimmed over the top.
Clean and prepare
The joints are cleaned and dampened so the new mortar does not dry out before it has cured.
Point and finish
Joints are filled and finished to match the existing work, so the wall looks right rather than looking repaired.
Protect while curing
New pointing is protected from frost, rain and strong sun while it sets.
Want someone to take a look?
Call 07464 695657 or send a photo on WhatsApp and you will get a straight answer on what it needs.
Repointing near you
E Stewart Roofing Ltd covers Glasgow, Ayrshire and Central Scotland. Pick your area for local detail, or call 07464 695657 if you are not sure whether you are in range.
Frequently asked questions
How often does a wall need repointing?
Good pointing lasts a long time, often several decades. It depends heavily on exposure: a west-facing gable in Ayrshire takes far more weather than a sheltered rear elevation, and it will need attention sooner.
Why is lime mortar used on old buildings?
Because it is softer than the stone and lets moisture escape through the joint. Hard cement pointing traps water in the wall and forces it out through the face of the stone, which then spalls and is very expensive to put right.
Can you repoint just one area?
Yes, and it is often the sensible thing to do. The finish is matched as closely as possible, though a patch on a weathered wall will always be slightly visible until it beds in.
Will repointing stop my damp?
It will if the damp is coming through open joints, which is common. It will not fix a leaking gutter, a failed flashing, or rising damp, so it is worth establishing the cause before spending money on the wall.
Can repointing be done in winter?
Not in a hard frost. New mortar that freezes before it has cured will fail, so this work is planned around the weather.