Finding cracks in your house can be alarming. In most cases, however, it is a simple case of ‘settlement’ (i.e. as the house settles into place in its environment). That said, subsidence cracks are not quite so benign, so it’s important to know what you’re dealing with when cracks in house walls show up. Usually, a Building Survey or HomeBuyer Survey will be able to detect any potential problems, such as subsidence cracks, before you buy.
In this article, we’ll explore the common types of cracks in house walls, what causes them, and when you should take action. Whether you’re a homeowner monitoring cracks or considering buying a property with visible wall damage, this guide will help you make informed decisions and protect your investment.
What causes cracks on walls?
It is important to note that many houses get cracks in the walls at some point. There are a number of possible causes, including:
- Road traffic vibrations if the property is near a busy road
- Temperature changes and humidity fluctuations in older properties
- Foundations settling (often on new build properties and extensions)
- Lack of supporting lintel on timber window frames which have been replaced with uPVC double glazing
- Hairline cracks can appear on newly plastered walls as they dry
All houses shift slowly over time. Cracks in internal walls of a house are not uncommon. Hairline cracks around doors and windows are usually down to this shifting and ‘settling’, particularly as these tend to be the weakest areas on a wall.
New build properties are notorious for cracks in house walls, and this is often down to the new lumber used to build the house. This lumber has naturally high moisture levels, so as it dries out it can experience slight movement. It takes about a year for this wood to completely dry out, so if you have cracks in a new build property, it is advised that you give it a year before repairing any cracks.
Interestingly, if you have left the house vacant for a few months or more, cracks in the house walls are natural. This is because, when you are living in the property you are controlling the temperature. Without climate control, expansion and contraction of the drywall can occur. Don’t worry though, these cracks can be simply retaped and painted.
Common types of cracks
There are several common types of cracks in house walls, each indicating different underlying issues. Understanding these cracks can help you assess their severity and whether they require professional attention:
- Hairline cracks – These are thin, superficial cracks often found in plaster or paint. They are usually caused by natural settling or minor shrinkage and are typically cosmetic rather than structural.
- Vertical cracks – Running straight up and down, these cracks often occur as a result of the house settling over time. Whilst generally less serious, they should still be monitored, as widening cracks could indicate foundation movement.
- Horizontal cracks – These are more concerning as they may indicate structural pressure, such as soil pushing against the walls or foundation issues. Horizontal cracks in brickwork or basement walls often suggest significant stress.
- Diagonal cracks – Cracks at a 45-degree angle are commonly seen around doors and windows. They can result from uneven settling of the foundation or shifting in the structure.
Other common terms also include ‘subsidence cracks’ and ‘structural cracks’. These both signify structural issues with the building and requires a professional to review.
When should I worry about cracks in walls?
If you spot cracks in a house which are over 25 millimetres wide, it is likely to be a serious problem. They could be subsidence cracks, indicating the house and its foundations are sinking, or they could indicate structural damage. In both these instances, major work will be required to fix the problem.
While cracks in the internal walls of a house are often harmless, indicating one of the issues we talked about above, they can sometimes be a sign of structural movement. If the cracks in a house run diagonally and are jagged, or are vertical and wider at top or bottom, it is time to engage the services of a chartered surveyor to assess the problem.
A big cause for concern is if you can see right through the crack to the outdoors. This is a sure-fire sign of subsidence.
As a general rule of thumb, you should be concerned if the cracks are:
- Wide
- Running diagonally
- Located above door frames
- Letting daylight through
How can I fix cracks in house walls?
Small cracks in walls can generally be plastered over with relative ease. However, with larger cracks, either wide or deep, you should consult a structural engineer. They will be able to accurately determine the cause and how best to fix it.
Should I buy a house with cracks in the walls?
Buying a house with cracks in the walls isn’t always a dealbreaker, but it’s important to understand what those cracks mean and whether they point to larger structural problems. Small cracks, which are common in older properties or newly plastered walls, are often superficial and unlikely to cause long-term issues. However, larger cracks will be indicative of more serious concerns.
Before making a decision, it’s essential to get the cracks properly assessed. A RICS surveyor or structural engineer can determine the root cause, severity, and potential cost of repairs. Their report will help you decide whether the cracks are manageable or a sign of deeper issues that could require significant work. If the repairs are costly, you may be able to negotiate a lower purchase price or request that the seller address the problem before the sale is completed.
Are structural cracks covered by insurance?
Insurance policies differ, so it is important to check what is and isn’t covered before taking out the policy. Often, a building insurance policy will cover some of the damage caused by subsidence cracks and ground heave but if the subsidence is caused by the materials used in the foundations or if the foundations don’t comply with Building Regulations, you could be out of pocket. Also, naturally occurring cracks due to settling are unlikely to be covered.
A qualified Chartered Surveyor will also be able to provide a fully accurate valuation of the property, to avoid you falling prey to property underinsurance, which – in the event of a serious structural issue – could be very costly.
This is why you should always engage a chartered surveyor before purchasing a property. While not all cracks in walls can be predicted, more serious issues can be identified early on, ensuring you aren’t left with a hefty bill and an unsafe property further down the road.
Whether you are considering a new property purchase or have concerns about cracks in your property, engaging the services of Robinson Elliott Chartered Surveyors is a good course of action.
With extensive experience in all types of property and areas in the South East of England, an assessment and Building Survey or HomeBuyer Report from us is the best way to ensure your property is safe and in a good state of repair for the long term.
Want to find out more? Get in touch with Robinson Elliott Chartered Surveyors today to discuss your concerns or requirements.
