What is home subsidence and how to identify it
Subsidence is a terrifying-sounding word. The idea of your home sinking beneath your feet conjures images of vast sinkholes and chasms.
Don’t worry, though. That’s not what subsidence is. In most cases, it’s a perfectly manageable condition, although it will require financial investment to keep on top of.
The areas of the UK most badly affected by subsidence are the East, London, and the South-East. That’s due to the high clay content in the soil.
However, subsidence could affect any home anywhere. This article contains more information about home subsidence and what you should watch out for.
What causes home subsidence?
Home subsidence is caused by the ground underneath the home shifting, causing the foundations to sink (or ‘subside’).
This usually relates to the earth’s water content. The moisture takes up space within the ground, effectively expanding it. As it’s used up, the ground contracts again.
You’ll find significant differences in the percentage of groundwater in the following cases:
- Clay-rich soil
- Homes surrounded by large trees
Water leaking around your home’s foundations might also wash away the earth underneath, especially if it’s made up of a significant proportion of sand and gravel.
However, subsidence technically arises from any change to the ground beneath the home. Thus, if the building is atop old mine shafts or an area significantly affected by earthquakes (unlikely, but not unheard of, in the UK), these could also make it sink.
Subsidence can also be caused by foundation damage. This is more likely in historic properties built before effective building regulations. Japanese Knotweed or tree roots might undermine them, or they could have been constructed using improper materials.
How to identify the signs of home subsidence
Subsidence is a crucial problem to watch out for when viewing a home. You might notice these signs in your own house, too. Here are some of the most common symptoms of home subsidence:
- Cracks in brickwork
- Cracks in plasterboard
- Doors won’t close
- Windows get stuck
Sticking doors or windows could also be a sign of damp. The water gets into the wooden structures and causes them to swell.
Cracks in the bricks themselves, though, are likely to represent a case of subsidence. Very few other faults could cause enough stress force to damage walls like this.
After it’s first constructed, a house should be given time to settle (known as ‘settlement’). A huge weight has been placed onto the soil. Thus, it’ll naturally adjust to a more stable and compact volume.
You’d typically allow around a year for this process. During this time, you can expect the building to show similar symptoms to subsidence, such as minor cracks. However, settlement is generally nothing to worry about.
When to seek professional help with home subsidence
So, when does home subsidence turn from a nuisance to a problem?
Generally, we recommend checking any cracks with a home survey. A Home Survey Level 3 (Structural Survey) is the best option, with an in-depth analysis of the cause, risk and repair solutions.
The wider the crack, the more severe the problem. If it’s approaching an inch or more, you should get surveyors and contractors in immediately. Your home is likely to be structurally compromised and thus could be unsafe.
Subsidence repairs should be covered by your home insurance (although you might have to pay a significant excess). The most common method to remedy the situation is underpinning, when the foundations are strengthened.
Seeking professional help is vital, whether you own the home or you’re considering buying.
A DIY repair won’t cut it here. When you come to sell the home, the estate agents, buyers, and other related stakeholders will want evidence of a reliable repair. You’ll also struggle to get a mortgage for any subsidence-affected building without an effective maintenance or repair plan.
Be on the lookout for subsidence with GB Home Surveys
Keep a ready eye out for home subsidence at all times. Catching it early (when you first notice cracks emerging) means it might cost much less to fix. Your home will remain safe and sturdy and retain its market value.
If you suspect your home suffers from subsidence, instruct a RICS-approved home survey. These deliver a standardised report explaining exactly what’s wrong and what to do next.
GB Home Surveys operates in local offices throughout the South-West, South Wales, and the West Midlands. All our RICS-registered chartered surveyors are qualified to do this work for you.
For more information or a friendly, informal chat, use the form below to reach out. We can’t wait to see what we can do to help you out.
