Summary
The mortar in a period property must be softer than the brick it surrounds, so that water moves out through the mortar joint rather than through the brick face. Lime mortar (typically NHL — natural hydraulic lime, grade 2, 3.5 or 5) achieves this; modern Portland cement does not. Repointing period brickwork with cement is one of the most expensive heritage mistakes — within 5–10 years the brick faces spall (blow out), permanently scarring the elevation. Reversing the damage often costs more than the original cement job.
Lime repointing is also slower work. Joints must be raked out to a depth equal to twice the joint width (typically 20–25mm), brushed clear of dust, dampened to control suction, and packed with mortar in two or three layers depending on joint depth. Each layer must cure before the next is added. Total time per square metre is 2–4 hours for an experienced operative. Cost reflects skill and time, not material.
This guide covers labour rates, lime mortar grades, raking-out methods, pointing styles (struck, weather-struck, recessed, flush, tuck-pointed), the conservation regulatory framework, and worked pricing for typical period property work. For broader brick/stone work see repointing and listed building consent.
Key Facts
- Standard lime repointing — £80–£120 per m² regional, £100–£160 per m² London
- Heritage / listed building repointing (NHL specified) — £180–£300 per m² depending on detail and access
- Mason / pointer day rate — £220–£320 regional, £280–£380 London
- Productivity — 4–8 m² per day per operative (less on listed/heritage)
- NHL2 (feebly hydraulic lime) — softest, for lime-mortar mid-walls and very soft handmade bricks
- NHL3.5 (moderately hydraulic lime) — most common for general period repointing in exposed brickwork
- NHL5 (eminently hydraulic lime) — strongest NHL, for chimneys, exposed copings, very wet locations
- Lime putty + sand mortar — non-hydraulic, used for internal pointing and very soft heritage brick
- NHL bag (25kg) — £18–£32 supplied
- Lime putty (25kg tub) — £35–£60 supplied
- Pointing sand (well-graded, sharp) — £6–£12 per 25kg bag
- Mortar mix — 1 part lime : 2.5–3 parts sand typical (1:2.5 stronger, 1:3 softer)
- Joint depth raked out — 20–25mm typical (minimum 2× joint width)
- Joint width domestic — 8–12mm typical
- Curing time per layer — 24–48 hours; final cure 28 days
- Frost-protection requirement — no application below 5°C; carbonation slow below 8°C
- Standard scaffold cost — £400–£900 for one-elevation scaffold (3–5 days hire)
- Tower scaffold (4m) — £80–£150 per week hire
- Cherry picker (12m, daily) — £150–£280
- Repointing-only quotes (no scaffold) — common above ground floor; customer aware they need scaffold
- VAT — 20% standard rate (0% on approved alterations to listed buildings until April 2012; standard rate now)
Quick Reference Table
Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.
Try squote free →| Elevation Type | Area | Time | Labour | Materials | Scaffold | Full Price |
|---|---|---|---|---|---|---|
| Single chimney stack | 4–8 m² | 1–2 days | £300–£700 | £30–£70 | £200–£400 | £530–£1,170 |
| Rear single-storey extension | 15–25 m² | 3–5 days | £900–£1,800 | £80–£150 | £400–£600 | £1,380–£2,550 |
| Front elevation, two-storey | 25–40 m² | 5–8 days | £1,800–£3,500 | £150–£250 | £700–£1,200 | £2,650–£4,950 |
| Full property repoint, four elevations | 100–160 m² | 4–8 weeks | £8,000–£18,000 | £500–£1,000 | £3,000–£6,000 | £11,500–£25,000 |
| Listed building, heritage work (rear elevation) | 20–30 m² | 6–10 days | £3,500–£6,500 | £200–£400 | £700–£1,200 | £4,400–£8,100 |
| Single chimney repoint + cap repair | 4–6 m² | 2–3 days | £600–£1,100 | £50–£100 | £200–£400 | £850–£1,600 |
| Internal cellar repoint (no scaffold) | 10–15 m² | 2–3 days | £700–£1,200 | £60–£100 | £0 | £760–£1,300 |
Detailed Guidance
Cement vs Lime — Why It Matters
A solid 9-inch (215mm) Victorian wall built in 1880 was constructed with brick fired in a beehive kiln (uneven temperature, soft to medium-hard) and laid in lime mortar. The wall's water-management strategy is: rain hits the face, some absorbs into brick, some absorbs into mortar; in dry weather, water evaporates out through mortar joints (which are deliberately softer and more permeable). The wall stays in moisture equilibrium.
If the wall is repointed with Portland cement:
- Cement is harder than the brick
- Cement is less permeable than the brick (and the original lime)
- Water now exits the wall through the brick face, not the joints
- Salt-bearing water concentrates at the brick face
- Frost cycles crystalise the salt, blow the brick face off ("spalling")
- After 5–10 years, the elevation looks like it's been sandblasted
Hence the rule: like-for-like. A wall built with lime mortar must be repointed with lime mortar.
NHL Grade Selection
Natural Hydraulic Lime (NHL) is graded by hydraulicity / strength at 28 days:
- NHL2 — softest. For internal walls, very soft handmade brick, and decorative pointing where no exposure is expected.
- NHL3.5 — medium hydraulic. The default for most UK period brickwork repointing in moderate exposure.
- NHL5 — most hydraulic. For exposed locations: chimneys, copings, wet southwesterly-facing elevations.
Lime putty (non-hydraulic) is used for the softest work — internal pointing of cob/clay walls, very early brickwork (pre-1700s).
Always specify the NHL grade in writing. "Lime mortar" is too vague; "NHL3.5 1:3 mortar with sharp sand from [supplier]" is clear and reproducible.
Mortar Mix Ratio
Standard ratios:
- 1 lime : 2.5 sand — stronger, less permeable, for exposed work
- 1 lime : 3 sand — softer, more permeable, for sheltered work
- 1 lime : 2.5 sand : 0.5 brick dust — for colour matching where reds dominate
Sand selection matters as much as lime grade. Use a sharp, well-graded sand (e.g. Portland Quarry or local equivalent) with grain size 0–4mm. Avoid soft building sand (too fine, doesn't compact). The sand colour ALSO matters — for historic colour matching, source local sand of similar tone.
Raking Out — Depth and Method
The original mortar must be removed to allow the new mortar to bond:
- Hand raking with chisel and lump hammer — slowest, safest, no risk to brick arrises. Best on listed work.
- Plug chisel or pointing chisel — manual, controlled, good for awkward joints.
- Angle grinder with raking disc — fast, but risks brick damage. Often prohibited on listed buildings.
- Routing tools (mortar routers) — semi-mechanical, controlled depth, acceptable on most non-listed work.
Depth: minimum twice the joint width. A 10mm joint must be raked out 20–25mm. Shallow raking gives the new pointing nothing to bond to.
After raking, brush all joints with a stiff hand brush to clear dust. Dampen with a fine spray immediately before pointing to control suction (a dry joint sucks moisture out of the lime mortar before it can carbonate).
Pointing Styles
UK period work uses several distinct styles:
- Flush pointing — mortar finished flush with brick face. Common on Victorian and Edwardian work.
- Weather-struck and cut — mortar pressed back at top, sloped down to expose lower brick edge. Sheds rainwater. Common on north-facing elevations.
- Struck (recessed top) — mortar pressed back at top, flush at bottom. Inverse of weather-struck.
- Bucket-handle (concave) — joint finished with a curved tool. Modern, occasionally found on later period work.
- Tuck pointing — fine raised band of pure-lime mortar laid into a wider joint. Very high-skill, used on Georgian and early Victorian.
- Recessed (flush back) — mortar set back 3–6mm from brick face. Decorative; reveals brick edge.
The match-existing rule applies. Look at sheltered (unweathered) corners of the property to see the original pointing detail, and reproduce it. Customers and conservation officers will notice if you switch styles.
Curing — The Carbonation Window
Lime mortar carbonates (sets) by absorbing CO2 from the air. The process is slow:
- Initial set: 1–7 days (mortar firm enough to apply next layer)
- Full carbonation: 28 days (final hardness)
- Cold weather: carbonation effectively stops below 5°C; very slow below 8°C
- Hot/dry weather: shrinkage crack risk if mortar dries too fast
In practice:
- April to October is the lime-pointing season
- Damp curing (light mist 2–4 times per day for first 3 days) prevents shrinkage
- Cover with hessian or hessian-and-polythene during curing to retain moisture and protect from sun/rain
- Never apply if frost is forecast within 48 hours
This is a customer-conversation point. "We can't pole-on with the work in November" — explain the carbonation window upfront.
Conservation Considerations
For listed buildings (Grade I, II*, II) and Conservation Areas:
- Listed building consent required for any material alteration; check with Local Authority Conservation Officer BEFORE starting
- Article 4 Direction (Conservation Areas) may require planning permission for repointing if it changes the property's character
- Mortar specification must be approved — Conservation Officer typically requires a written method statement and material specification
- Recording of existing condition — photographs of every elevation before work commences
- Sample panel — a 1m² test patch approved by the Conservation Officer before the full job
These approvals add 4–8 weeks to the project timeline and £400–£800 in conservation officer fees / specialist surveys. Quote this as a separate scope item, not a hidden extra.
Common Site Overruns
- Cement-pointing discovered — pre-existing cement repointing must be removed before lime can be applied. Sometimes the whole elevation has been done.
- Brick spalling — some bricks have already lost their face; replacement bricks needed (£3–£15 each for handmade or salvage; £0.40–£1.20 for common stock).
- Soft mortar core — wall built with lime + ash + clay mix; pointing mortar penetrates and disturbs the core.
- Render or stucco found beneath an apparently-bare brick wall — pointing scope changes entirely if render is to be retained.
- Customer's "small chimney" is actually 8m² and requires scaffold — pricing must include access.
Frequently Asked Questions
Can I use a cement-lime gauged mortar?
A gauged mortar (Portland cement + lime + sand) is sometimes acceptable for moderately-exposed Victorian/Edwardian work where pure lime would be too soft. Typical ratio: 1 cement : 3 lime : 12 sand. NEVER use straight cement mortar on period brickwork. For listed buildings, gauged mortar is usually NOT acceptable — Conservation Officers will require pure NHL or putty lime.
How long does lime mortar repointing last?
Properly executed NHL3.5 pointing in moderate UK exposure: 80–100+ years before re-pointing is needed. Lime is the original specification for a reason — when right, it lasts longer than the building's anticipated lifespan.
Can I repoint in winter?
The carbonation rule means October to March is largely a no-go for external lime pointing. Some specialists use lime mortars with proprietary additives (e.g. Roundtower Limecrete with frost-resistant additives) for late-season work, but always check the manufacturer datasheet and provide additional protection. Most contractors quote spring-to-autumn delivery only.
Do I need to use the same colour mortar as the original?
For listed and conservation-area work, yes. Use sample panels and approved colours. For non-listed period property, colour-matching is usually a quality requirement (the elevation should look continuous after pointing) but the local mortar/sand colour is rarely identical to the new mortar — small visual contrast is acceptable on non-heritage work.
What about modern materials like Roundtower or limecrete?
These are proprietary lime-based mortars formulated for specific applications (paving, exposed surfaces, frost-prone conditions). They are acceptable substitutes for traditional NHL where the manufacturer's specification is approved by the Conservation Officer (on listed work) or matches the application requirements.
Regulations & Standards
Planning (Listed Buildings and Conservation Areas) Act 1990 — listed building consent regime
Town and Country Planning Act 1990 — conservation area protections
National Planning Policy Framework (NPPF) — heritage chapter (Chapter 16)
BS EN 459-1:2015 — Building lime — definitions, specifications and conformity criteria (NHL grades)
BS EN 998-1:2016 — Specification for mortar for masonry — rendering and plastering mortar
BS EN 998-2:2016 — Specification for mortar for masonry — masonry mortar
Historic England: Practical Building Conservation series — authoritative guidance on lime mortars
Society for the Protection of Ancient Buildings (SPAB): Technical Q&A — practical conservation guidance
Historic England: Practical Building Conservation — Mortars, Renders & Plasters — primary authoritative reference
SPAB: Lime mortars technical guidance — industry body guidance
Society of Lime Plasterers — trade body resources
repointing — general repointing technique
listed building consent — when consent is required
brick types and bonds — period brick specification
mortar mixes — mortar mix ratio reference
period property damp — damp diagnosis in period properties