How much mortar do I need to repoint 1m² of brickwork?

For standard UK bricks (215x65mm) with 10mm joints raked to 15mm depth, you need approximately 3-4 litres of mixed mortar per m² of wall. This varies with joint width and raking depth. Wider joints (12mm) or deeper raking (20mm) will increase the volume proportionally. Our calculator works this out precisely for your specific dimensions.

What mortar mix should I use for repointing?

For general repointing of modern brickwork, use a 1:1:6 mix (1 cement : 1 lime : 6 sand) or a 1:4 cement:sand mix with plasticiser. For older buildings (pre-1920) and conservation work, use a lime-based mortar (1:3 lime putty:sand) — cement-based mortar can damage soft historic bricks by being too hard and preventing moisture movement.

How deep should I rake out joints before repointing?

Rake out joints to a minimum depth of 15mm (twice the joint width) to ensure the new mortar has enough depth to key into the joint. For best results, rake to 20mm. The joint should be square-backed and free of loose material. Use a plugging chisel or mortar rake — avoid angle grinders which can damage the brick arrises.

What sand should I use for repointing mortar?

Use sharp sand (also called building sand or bricklaying sand) for repointing mortar. For a colour match with existing pointing, source sand locally or add a mortar tint. Avoid using soft sand (plasterer's sand) on its own as it produces a weaker mix. Many merchants sell pre-blended repointing sand with lime already included.

How long does repointing last?

Good-quality repointing should last 50-100 years on a sheltered wall, or 25-50 years on an exposed wall. The main factors affecting longevity are mortar mix quality, correct joint preparation, weather during application, and aftercare (keeping the joints damp for 2-3 days to allow proper curing). Lime mortar is more flexible and can last longer on older buildings.

Repointing Calculator — How Much Mortar for Repointing?

Calculate the mortar, sand, cement and lime needed for repointing brickwork. Supports standard, engineering and London stock bricks.

Wall Area

Total area of brickwork to be repointed

Brick Type

All use standard UK 215x65mm face size

Joint Width

Width of mortar joint. Standard: 10mm

Raking Depth

Depth joints are raked out. Minimum: 15mm

Mortar Type

Use lime mortar for pre-1920 buildings

Include wastage allowance

Adds 15% extra for dropped and unused mortar

Wastage Percentage

15% is typical for repointing work

Price Per 25kg Bag (optional)

Average price per bag for cost estimate

How We Calculate This

This calculator determines the volume of mortar needed to fill the horizontal (bed) and vertical (perp) joints in your brickwork, then converts that volume into quantities of sand, cement and lime based on your chosen mortar mix.

The formula

Mortar volume = Wall area x (Horizontal joint volume + Vertical joint volume) per m²

For standard bricks (215x65mm with 10mm joints):

Courses per metre height: 1000 / 75 = 13.33
Horizontal joint volume per m²: 13.33 courses x 1m x joint width x raking depth
Vertical joints per course per m: 1000 / 225 = 4.44
Vertical joint volume per m²: 4.44 x 13.33 x 65mm height x joint width x raking depth

Mortar mixes

1:1:6 (cement:lime:sand): General-purpose repointing mortar. Good workability and flexibility.
1:4 (cement:sand + plasticiser): Modern alternative. Stronger but less flexible than lime-based mixes.
1:3 (lime putty:sand): Heritage and conservation mortar. Softer, more breathable — essential for pre-1920 buildings.

Dry volume conversion

Wet mortar shrinks approximately 33% from the dry mix volume, so we multiply the required wet volume by 1.33 to calculate the dry material quantities needed. Sand density: 1500 kg/m³. Cement density: 1500 kg/m³. Lime density: 600 kg/m³.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Verify with your supplier.