I have cracks in my walls, is this subsidence?

This is a frequently asked question by those worried about subsidence.

Building Surveyors and Structural Engineers use BRE guidelines to categorize, and this helps assessors determine whether the cracks are likely to affect the property and what repairs are required. 

“BRE Digest 251, Assessment of damage in low- buildings”

Category of damage, 

Description of typical damage

0 Hairline cracks of less than about 0.1mm which are classed as negligible. No action required. 

1 Fine Cracks which can be treated easily using normal decoration. Damage generally restricted to internal wall finishes, cracks rarely visible in external brickwork. Typical crack widths up to 1mm. 

2 Cracks easily filled. Recurrent cracks can be masked by suitable linings. Cracks not necessarily visible externally; some external repointing may be require to ensure weather- tightness. Doors and windows may stick slightly and require easing and adjusting. Typical crack widths up to 5mm.

3 Cracks which require some opening up and can be patched by a mason. Repointing of external brickwork and possibly a small amount of brickwork to be replaces. Doors and windows sticking. Services pipes may fracture. Weather tightness often impaired. Typical crack widths are 5 – 15 mm or several of say, 3mm.

4 Extensive damage which requires breaking -out and replacing sections of walls, especially over doors and windows. Windows and door frames distorted, floor sloping noticeably*. Walls leaning or bulging noticeably*, some loss of bearing in beams. Service pipes disrupted. Typical crack widths are 15-25mm but also depends on number of cracks.

5 Structural damage which requires a major repair job involving partial or complete rebuilding. Beams lose bearing, walls lean badly and require shoring. Windows broken with distortion. Danger of instability. Typical crack widths are greater than 25mm but depends on number of cracks. 

*Local deviation of slope, from the horizontal or vertical, of more than 1/100 will normally be clearly visible. Overall deviations in excess of 1/150 are undesirable.

BRE Group

Which cracks are due to foundation movement?

Cracks that are Category 3 or above are considered to be caused by foundation movement. 

Cracks due to foundation movement would usually show externally and internally and can extend through dpc into the foundation. They may appear as stepped cracking in brickwork, or diagonal in walls. They tend to look wider at the top. 

Are there any other signs of subsidence?

Yes, other signs can include sinking floors and/or windows and doors sticking. 

When should I call an expert like Geobear?

Cracking in categories 1 – 2 is not usually considered to be caused in relation to structural movement. It is recommended that these are monitored for any changes. If cracks appear as described at Category 3 it’s time to call the expert.

What can I expect from Geobear?

We have qualified professionals who can visit the site and assess the zone of treatment. 

The zone of treatment is determined by the information available at the time of the visit. This will include our own visual inspection and any reports you may have (insurance/ surveyor / structural engineer/ drain survey/site investigation). 

Our proposal will include a price for the work, a treatment plan, other important notes, and T&Cs.

How long will it take?

Our residential works can be completed in as little as 1 day. 

Need our assistance? 

Call us on 0800 084 3503 or fill our online form below.