Cracks in walls are one of the most common concerns raised by homeowners and property buyers.
In many cases, cracking is relatively minor and associated with normal building movement, drying shrinkage or deterioration of decorative finishes. However, some cracks can indicate more significant movement and should be properly investigated before simply being filled and redecorated.
At Stokemont, our Building Surveyors regularly inspect cracking in residential and commercial properties across England & Wales.
The important point is not simply to look at the crack itself, but to understand why it has formed, whether movement is ongoing and whether the underlying cause needs to be addressed before repair.
Why Do Cracks Appear in Walls?
Buildings are rarely completely static. Construction materials naturally expand, contract, dry and move throughout the life of a property.
Some of the most common causes of cracking include:
- drying and shrinkage of plaster;
- thermal movement;
- minor settlement following construction;
- movement where different building materials meet;
- moisture-related movement;
- alterations to the structure;
- defective workmanship;
- foundation movement; and
- structural movement affecting walls, floors or roofs.
A crack therefore does not automatically mean that there is a serious structural problem.
We see a significant amount of cracking that can be attributed to natural building movement, particularly where materials expand and contract as temperatures and moisture levels change.
Periods of unusually hot weather, prolonged dry conditions or particularly wet winters can exaggerate movement within certain materials, making existing cracks more noticeable and, in some cases, causing new cracking to appear.
This does not automatically indicate a structural defect. What matters is the location, width, direction and pattern of the cracking, together with whether it appears to be changing over time.
Hairline Cracks in Plaster
Fine cracks within internal plaster are extremely common.
They may appear following redecoration or replastering, as a result of minor building movement, or where different materials meet and respond differently to changes in temperature and moisture.
Where a crack is clearly limited to the plaster finish and there is no evidence of ongoing movement, it can often be repaired relatively easily.
Step-by-Step Guide to Repairing Minor Plaster Cracks
1. Prepare the crack
Carefully open the crack slightly using a suitable scraper or filling knife. The aim is to remove loose material and create enough space for the filler to bond properly rather than simply sitting on the surface.
2. Apply the filler
Remove any dust and loose material before applying a suitable ready-mixed filler or plaster repair product. A wire brush is a good way to do this.
Work the filler firmly into the crack so that it fills the affected area rather than simply covering the surface.
3. Smooth and allow to dry
Smooth the filler as level as possible with the surrounding wall and allow it to dry fully in accordance with the manufacturer’s instructions.
Drying times will vary depending on the product and the depth of the repair.
4. Sand and redecorate
Once completely dry, lightly sand the repaired area with fine abrasive paper until it is smooth and level with the surrounding finish.
The wall can then be primed where necessary and redecorated to match.
Stokemont Tip
For minor recurring plaster cracks caused by small amounts of normal movement, a flexible decorating filler can sometimes perform better than a rigid filler, as it is better able to accommodate limited movement.
Always follow the manufacturer’s instructions and use appropriate protective equipment when preparing, sanding and applying repair products.
What If the Crack Keeps Coming Back?
A crack that repeatedly reappears after repair deserves closer attention.
Filling and redecorating treats the visible symptom, but it does not resolve the underlying cause.
If the same crack repeatedly opens, becomes wider or is accompanied by other signs of movement, further investigation may be appropriate before carrying out another cosmetic repair.
Particular attention should be given to cracking that:
- increases noticeably over time;
- extends through the masonry rather than just the plaster;
- appears diagonally around doors or windows;
- follows mortar joints externally in a stepped pattern;
- is accompanied by sticking doors or windows;
- appears alongside distortion of floors or walls; or
- develops suddenly without an obvious explanation.
These signs do not automatically mean that a property has a serious structural defect, but they should be considered in context.
Don’t Panic — But Don’t Ignore It
Cracking is extremely common in buildings and does not automatically indicate structural failure.
Equally, it is rarely sensible to assume that every crack is purely cosmetic without first considering why it has appeared.
The correct approach is:
- Understand the cause
- Establish whether movement is ongoing
- Address the underlying issue where necessary
- Repair the crack
Once the cause has been properly understood, the appropriate repair can be undertaken with far greater confidence.
Concerned About Cracks in Your Property?
If you have noticed cracking and are unsure whether it is cosmetic or potentially more significant, Stokemont can inspect the property and provide professional advice on the likely cause and appropriate next steps. Through our Defect Analysis Reports we can inspect and advise on what is causing the issue and more importantly what needs to be done to solve it.
Contact Stokemont today to discuss cracking or movement within your property.
