Lime where lime belongs.

The one rule

Mortar is meant to be the sacrificial part of a wall. It should be softer and more breathable than the brick or stone around it, so that moisture leaves through the joint and the joint wears instead of the brick. Most of London's terraces, squares and mansion blocks were built with lime mortar for exactly that reason. Repoint them in hard cement and the water has nowhere to go but through the brick face, which then blows in the first hard frost. You can see the result on half the streets in London: crisp grey joints and crumbling, pock-marked brick.

What a proper repointing job involves

1. Raking out by hand or with a fine tool to about twice the joint width, without widening the joint or chipping arrises. Disc cutters on narrow Georgian joints are the usual sign of a bad job.
2. Matching the mortar: lime type, sand colour and grading, and the joint profile (flush, weather-struck, bucket-handle, tuck). On a listed front the council may ask for a sample panel.
3. Dampening and packing the joint in layers, then finishing when it has firmed, and protecting it from sun and frost while it cures. Lime needs weeks, not hours.

Tuck pointing

A London trick from the eighteenth and nineteenth centuries: the joints are filled with a mortar coloured to match the brick, then a fine white or black line is set into the surface so that cheap brickwork reads as fine gauged work from the pavement. It survives across Bloomsbury, Islington and Kensington. Restoring it is skilled work and is priced by the metre of line, not the square metre of wall.

Brick repair, replacement and tinting

Spalled or shattered bricks are cut out and replaced with matching reclaimed or new stocks, laid in lime. Where a new brick is a shade off, or a repair stands out, the face can be tinted with mineral stains that soak in rather than sit on top, so the patch disappears. Cracked walls are usually stitched with stainless helical bars set in the joints before repointing; that is a structural question for a surveyor first.

Stone repair

Small repairs to sills, steps and cornices are done with lime-based mortar repairs; larger losses are cut out and a new piece of matching stone indented. Published 2026 guides quote minor stone repairs from about £150 to £500 and a sill repair in the £150 to £350 range; a new indent is priced per piece.

Cost

2026 cost guides put brick repointing at about £50 to £60 per square metre and stone at £60 to £100, with a typical semi-detached house in the £4,000 to £5,000 range. A London terrace front with scaffold, lime mortar and a conservation officer involved will sit above the national guide. Get the mortar specification in writing before comparing prices.

Consent

Councils generally treat small like-for-like patch repointing of a listed building as maintenance, but substantial repointing, or a change of mortar or joint style, usually needs listed building consent. The rules, and penalties, are on the consent page.