How can I tell if the type of cracks in my house are serious?
Cracks in your house can vary in length, width and direction. Typically, larger cracks (those bigger than 15mm in width) are a cause for concern and should be inspected by a structural engineer.
Subsidence cracks usually appear quite suddenly, rather than slowly over time. They are usually diagonal and wider at the top than at the bottom, and often found around doors and windows, according to the Association of British Insurers.
Types of cracks:
Negligible - hairline cracks less than 1 mm in width, which can be easily fixed by redecorating.
Slight - cracks between 1 and 5mm in width, which can be fixed with filler. Exterior cracks may need re-pointing.
Moderate - cracks between 5 and 15mm may need professional building work, including underlying repairs.
Severe - cracks up to 25mm wide could be a sign of structural damage and should be inspected and repaired by a professional.
Very severe - any crack above 25mm in width indicates serious structural damage and will need major repair work, which could include underpinning and rebuilding. A large crack running in a vertical direction can also be a tell-tale sign of structural damage.
If you’re worried about cracks in your house – no matter how large or small – seek the help of a building professional or structural engineer as soon as possible.