Cracked or damaged brick and stonework
Visible damage to brickwork or stonework - whether that's a crack, a spalling surface, or a section that has physically broken - is something that tends to get noticed and then left. In some cases that's reasonable. In others, leaving it carries real risk.
This page explains how to tell the difference, what causes masonry damage in the first place, and what the repair options are.
Types of masonry damage
Cracking
Cracks in masonry can run through mortar joints only, through individual bricks or stones, or diagonally across both.
The pattern matters:
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Vertical or stepped cracks following mortar joints are commonly caused by differential settlement or thermal movement. Many are stable and manageable.
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Diagonal staircase cracking across several courses is often associated with foundation movement or differential settlement and warrants closer inspection.
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Horizontal cracks (running along a bed joint across a wide area) can indicate wall tie failure in cavity construction, or overloading of the wall.
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Cracks around lintels or window reveals often indicate lintel failure, corrosion, or insufficient bearing.
Spalling
Spalling is when the face of a brick or stone flakes or pops off, leaving a recessed, rough surface. It is caused by moisture trapped within the masonry surface cycling through freeze-thaw. As water within the material freezes, it expands just below the surface, eventually causing the face to break away.
Spalling is particularly associated with hard cement pointing on soft, old brick or stone. When a soft, porous masonry unit is pointed with a rigid, non-breathable cement mortar, moisture that would normally evaporate through the joint is forced back through the brick face. The brick spalls; the mortar stays intact. This is one of the most common causes of accelerated masonry deterioration we see on older Yorkshire properties.
Frost damage
Similar in mechanism to spalling but affecting the whole unit. Severely frost-damaged bricks crumble at the edges or break apart. This is terminal for the affected unit - it needs replacing.
Impact damage
Localised physical damage from vehicles, tools, or accidental impact. This is typically cosmetic unless the structural integrity of the unit has been compromised.
Cosmetic damage vs structural damage
Many homeowners are unsure whether cracking or masonry damage is a building risk or just an aesthetic issue. The short answer is: it depends on the pattern, extent, and whether it is active.
Cosmetic damage - small isolated cracks, localised spalling, minor surface loss - does not affect structural integrity, but it does allow water in, which can accelerate deterioration. It should be monitored and repaired to prevent it becoming a structural issue.
Structural damage - wide cracks, cracks in active structural elements, wall tie failure, lintel movement, widespread loss of masonry across a load-bearing section - needs proper assessment before repair begins. Patching over a structural defect without addressing the cause is not a repair; it's concealment.
How to tell if cracks are active or stable
An active crack is still moving. A stable crack has finished moving and is now static.
Signs a crack may be active:
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The crack has fresh edges (sharp, unweathered)
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Debris is visible within the crack
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The crack is still widening or changing shape
Signs a crack may be stable:
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Rounded or weathered edges
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Paint or render has crossed the crack and is also cracked
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No change in width over a period of monitoring
A simple test is to stick a small strip of paper or card across the crack with adhesive at both ends. If the paper tears or pulls away from one side over the following weeks, the crack is still moving.
Repair options
Individual brick replacement
Where a single brick has spalled beyond repair or is physically damaged, it can be cut out and replaced with a matching unit. Getting a close match in older brickwork can require sourcing reclaimed brick. The new brick is bedded and pointed in a mortar matched to the building.
Stone repairs
Damaged stonework can be repaired with stone indent pieces (a new piece of stone inserted into a prepared void) or with repair mortars where the damage is surface-level. For carved or shaped stone, a specialist mason may be required. We carry out standard masonry repairs and will be clear about what falls within our scope and what requires other expertise.
Resin or mortar consolidation
Where masonry has loose or delaminating faces but is structurally in place, consolidation with appropriate mortar or resin can stabilise the surface. This is a specific technique and not appropriate for all situations.
Repointing alongside masonry repair
Masonry repair rarely happens in isolation. Damaged brick or stone is usually found alongside failing mortar joints - the same moisture ingress that caused the masonry damage has also attacked the joints. We typically carry out masonry repair alongside lime mortar repointing or cement mortar repointing to address both problems at the same time.
Listed buildings and older properties
If the property is listed, any repair to external masonry will typically require consent. The correct repair material is also non-negotiable on a listed building - a hard cement mortar is not an acceptable material on a listed stone or soft brick building, regardless of what a contractor might suggest. We understand the requirements for lime-based repairs on older and listed buildings. If consent is required, we can advise on the process.
When to call a structural engineer first
You should have a structural engineer assess the building before repair work begins if:
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Cracks are wide (over 5mm), multiple, or follow a pattern associated with foundation or structural movement
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Walls are visibly leaning or bowing
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There are signs of wall tie failure in a cavity wall (horizontal cracking along bed joints at regular intervals, or bulging of the outer leaf)
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The building has had significant recent movement following nearby excavation, tree removal, or drainage works
Masonry repair in these situations is secondary to understanding and stabilising the structural cause. We will always tell you honestly if what we're seeing suggests a structural issue rather than a repair job.
Frequently asked questions
Q1. How do I know if a crack in brickwork is structural or just cosmetic? Cosmetic cracks are typically hairline, run along mortar joints, and do not pass through the brick face itself. Structural cracks are generally wider (over 3 mm), may step diagonally through both brick and mortar, are tapered (wider at one end), or follow a pattern suggesting differential settlement. If you can insert a coin into a crack, get it looked at. Northern Seal & Joint can assess masonry cracks and advise whether the cause needs investigation beyond the visible damage before any repair is carried out. Q2. When should I be worried about cracked brickwork? Be particularly alert to cracks that have appeared or widened recently, cracks that are wider than a few millimetres, diagonal cracks running from door and window corners, cracks accompanied by bowing or bulging of the wall face, and any cracking near a load-bearing element. Historic cracks that have remained stable for many years are usually cosmetic. If in doubt, have it inspected - a simple assessment costs far less than finding out later that progressive movement has continued unchecked. Q3. Can cracked or spalled bricks be repaired without full replacement? Yes, in many cases. Shallow spalling (where the brick face has broken away) can be repaired using compatible masonry repair mortars matched to the original brick colour and texture. Cracked bricks can sometimes be stabilised and pointed over if the crack is minor and the brick is otherwise intact. Full replacement is required when the brick is structurally compromised or badly damaged. Northern Seal & Joint assesses each brick individually and recommends repair where possible, replacement only where necessary. Q4. Can you match the colour and texture of old brick or stonework? We make every effort to do so. For brick repairs, tinted repair mortars can be mixed to closely match the existing material. Where full brick replacement is needed, salvaged matching brick or a carefully selected modern equivalent can often be sourced. Stone repairs on older Yorkshire properties can be matched using natural stone fillers or, for larger losses, with appropriate reclaimed stone. An exact match is not always achievable, particularly on very old or unusual materials, but we aim to make repairs as visually unobtrusive as possible. Q5. Are there special considerations for listed buildings or conservation areas? Yes. Listed buildings require consent for most external repairs beyond like-for-like maintenance, particularly if the repair method or material differs from the original. Properties in conservation areas may also face restrictions on changes to external appearance. The use of appropriate lime-based mortars and materials compatible with the original construction is typically required on heritage properties. Northern Seal & Joint has experience working on older Yorkshire properties and can advise on what is appropriate; for listed buildings, we recommend confirming requirements with your local authority before work starts. Q6. How much does masonry repair typically cost? Costs vary considerably depending on whether the work is cosmetic or structural, the extent of the damaged area, access requirements and material matching. Small localised repairs are relatively modest; scaffold-required work on multiple elevations will cost more. Northern Seal & Joint provides clear itemised quotes after inspection so you know exactly what is included. We do not carry out structural engineering work, but can advise when a structural engineer's assessment is recommended before masonry repairs proceed.
Recent local work -
Not sure what you're dealing with?
If you have visible cracking or masonry damage and aren't sure whether it's cosmetic or structural, or what caused it, a Building Leak & Damp Inspection is a good starting point. We look at the building as a whole and give you an honest assessment before recommending any work.