Should I worry about cracked walls?
Noticing a crack in a wall can be deeply unsettling. Why has it emerged? Will it compromise the entire building?
A general ‘crack in the wall’ is impossible to diagnose off the cuff. The wall material is clearly under some sort of stress, but the severity of this will depend on the root cause.
In most cases, cracks in walls are manageable. They can either be repaired, rebuilt, or monitored and maintained with an ongoing action plan. That said, it’s best to ask a knowledgeable professional for their advice.
So, should you worry about a cracked wall in a home you’ve viewed? This page contains everything you need to know.
Causes of cracked walls in homes
As we mentioned in the introduction, a crack in the wall means the material is under some kind of stress. More serious causes could be subsidence or poor-quality construction; less severe (and widespread) reasons could be soil settlement or plasterboard degradation. They all need some work, but to varying degrees.
Remember, most of these are manageable. Unless you see a structural wall clearly crumbling or leaning, there is almost always some way to remedy the issue. Again, you need the professional opinion of an experienced contractor or chartered surveyor. Don’t commit until you know for sure.
For most buyers, the real potential issue isn’t the crack itself; it’s the price of repairing or maintaining it safely.
Here are some of the most common causes of cracked walls:
Moisture in the room causing plasterboard degradation
Humidity is the bane of plasterboard, the material covering most internal walls in your home. Unfortunately, this is the British Isles. It’s wet. On some level, there’s no way around this.
Homes should be constructed with efficient ventilation. Opening windows are a prime example, and can be used to ‘purge’ the air inside. Extractor and ceiling fans, dehumidifiers, and brick and eaves ventilation systems all play a significant role in moisture regulation, too.
If a room hasn’t been appropriately ventilated (or a pipe has burst in the wall), this moisture will seep into the plasterboard, causing it to expand. This creates the cracks you can see.
The cracks themselves are nothing to worry about. They can be smoothed and painted over.
The real problem is the cause of the cracks. You should investigate for leaking pipes or consider the cost of installing better ventilation.
Weather causing degradation of external building materials
Although we don’t usually think of it this way, a building’s walls and roof protect us from the weather. Rain, sun, wind, snow, ice, extreme temperatures, etc., all work together to form a cosy, protected space.
Over time, the weather (particularly extremes such as acid rain or storms) will degrade the materials. Nothing lasts forever, no matter how well it was built. For example, rain and ice can degrade the mortar used between bricks, causing the wall to shift and cracks to form.
Concrete crumbling is another well-documented example, caused by the material reacting with salt and water.
In most cases, the degrading material can be replaced. This could be a major or minor operation, and you’ll need some professional inspections and advice.
Soil settlement
When a new home or extension is constructed, a significant chunk of land is dug away to lay the foundations. This aerates the soil underneath. Once the foundations are down and the house is built, this weight compresses the ground down.
It can take up to a few years for the soil to stop moving, although it’s usually within 12 months. The main factor in this timeframe is water drainage pathways.
If you’re looking at a newer home, this (completely normal) could be why you see cracks in the plasterboard. However, general soil settling shouldn’t lead to significant structural issues. Wide or long cracks in brickwork may represent a more severe problem.
Subsidence
Subsidence sounds like a terrifying phenomenon, but actually affects around 20% of all British homes. It’s when the ground underneath your foundations sinks (‘subsides’). This puts extra stress on the walls, now holding the house together at a slightly different angle.
Subsidence can be caused by many things, but the most common are:
- Soil with a heavy clay content (‘reactive soil’)– this expands and contracts significantly with the presence (or lack thereof) of water.
- Tree roots– the roots themselves occupy space, penetrate foundations, and also draw water from the soil.
- Japanese Knotweed – this invasive plant grows quickly, undermining soil and foundations.
- Drains or mining shafts– nearby underground structures create more ground instability, especially if they collapse.
- Floods– again, this is related to the sudden change in soil water content.
Subsidence is usually manageable, although it’s much more difficult to get a mortgage. Speak to an expert for the best advice in your situation.
Over time, the weather (particularly extremes such as acid rain or storms) will degrade the materials. Nothing lasts forever, no matter how well it was built. For example, rain and ice can degrade the mortar used between bricks, causing the wall to shift and cracks to form.
Concrete crumbling is another well-documented example, caused by the material reacting with salt and water.
In most cases, the degrading material can be replaced. This could be a major or minor operation, and you’ll need some professional inspections and advice.
Drainage damage
Houses are supposed to channel water away from your walls and foundations, with things like:
- Drains
- Gutters
- Drainpipes
- Slope design
- Roof tiles
If these systems aren’t correctly installed or maintained or get damaged, water collects around the foundations. This can wash away soil and lead to subsidence (see above). You could also end up with an internal leak. Both of these lead to cracked walls.
In this case, the affected part and damaged areas must be repaired or replaced. The cost depends entirely on how much damage has been done.
Poor-quality construction (including foundations)
Finally, a poor-quality structure will be at higher risk of cracks in the walls.
You’d expect to see these issues on the non-structural walls, but they could be anywhere. For instance, if a wall isn’t straight, the brick, stone, wood or concrete will struggle. Over time, the strain will cause a crack in one side of the wall.
Foundations must also be laid to a strict set of standards. Incorrectly installed slabs may lead to an unlevel building, putting undue stress on the walls. This damage could develop and get worse over time.
You’ll often need to seriously consider if the home is worth the repair price (and risk).
Ask an expert for their advice – should you worry?
Before committing to buy a home, you should ensure you won’t end up with buyer’s regret. Don’t get stuck in an unhappy, costly situation.
At GB Home Surveys, we can help.
A RICS home survey is one of the best ways to protect your investment. We usually recommend at least a Level 2; however, if you’ve found cracks during a viewing, you might want to consider a more structurally-focused Level 3.
For more information on wall cracks and how a home survey helps you identify the hazards, feel free to get in touch with us. We’d be happy to have an obligation-free, friendly chat about how the process works and why it’s so important.
Use the form below to send us a message. We’ll get back to you as soon as possible.
