What are the risks of buying a house with subsidence? 

Buying a property with subsidence comes with a particular set of challenges.

Costly repairs 

Subsidence repair can be expensive as you’ll need to address the cause, not just fix the visible damage. Fixing the root cause may involve managing trees, repairing leaky or damaged drains or underpinning the foundations of the property. Underpinning involves strengthening or repairing the ground beneath an existing building to make sure its foundations are strengthened. Traditional methods of underpinning such as mass concrete can be highly disruptive and costly, however, less intrusive methods such as resin injection can be used.  

Problems getting a mortgage 

If the property is currently experiencing subsidence, then you usually won’t be able to take out a mortgage. You can still buy the property with cash and then pay for subsidence repairs. 

You should usually be able to secure a mortgage on a property with historic subsidence that has been addressed. However, the insurer will want to see details of any repairs made and a structural engineer’s report. 

High insurance costs 

Getting building insurance can also be extremely difficult. Most standard insurance policies refuse to cover homes with ongoing subsidence. Some insurers will increase premiums significantly and add high compulsory excesses, which often start at £1,000 or more.  

Signs of subsidence to look out for when viewing a house 

Although subsidence occurs below the surface, there are some obvious signs inside and outside of the house to watch out for when you’re viewing a property. Some of the most common signs include: 

• Cracks that are wider then 3mm, especially near doors and windows

• Diagonal cracks that are wider at the top and thinner at the bottom

• Gaps between a skirting board and the floor

• Sloping or uneven floors

• Doors and windows that stick or have become misaligned

• Cracks at the joints where an extension meets the main house

• Rippling or wrinkled wallpaper where walls meet the ceiling

It’s worth noting that not all cracks are a sign of subsidence. Fine or hairline cracks are often an indication that the building has naturally settled over time or has experienced seasonal temperature changes. These cracks are cosmetic and considered normal. 

What causes subsidence? 

Subsidence is primarily the result of soil shrinkage, which is usually caused by moisture loss, natural compression or the washing away of soils. The key triggers include: 

Clay soils: this type of soil is particularly sensitive to weather changes. During periods of heavy rain, clay soils will absorb large amounts of water and expand. In hot weather or drought conditions clay soils will dry out and contract, causing the ground to shift or move unevenly.  

Tree roots: thirsty trees such as oak and willow draw out significant amounts of water from the ground through their roots, causing the soil to shrink.  

Leaking pipes or drains: excess water spilling from damaged or burst pipes can over saturate the ground or wash away fine soils beneath the property. 

Should I buy a house with subsidence? 

Again, it depends. There’s no right or wrong answer, but it does come to the current state of the property and how much of a risk you’re willing to take. Here are some options to consider: 

Go ahead with sale but apply certain conditions. Ask the seller to make remediation works or an underpinning guarantee a condition of exchange before you agree to the sale. 

Renegotiate the price. If the survey has flagged subsidence but the seller hasn’t lowered the sale price, you can ask for a reduction. Obtaining a structural engineer's report will help support your request. 

Step away from the deal. If the cause of subsidence hasn’t been identified and the seller won’t negotiate on the price, it may be best to find another property.  

Whatever you decide to do, you should take specialist advice before making a commitment.  

If you’re considering buying house with subsidence, seeking advice from a qualified structural engineer or subsidence specialist will help. Ground engineering experts such as Mainmark offer modern ground improvement and foundation repair techniques that may provide less disruptive alternatives to traditional underpinning methods. 

In short, buying a house with subsidence isn’t necessarily a bad investment, however, it does need a lot of careful planning and professional advice. An active case of subsidence can lead to expensive repair and insurance costs and mortgage difficulties.  

Before you make a decision, you should understand the cause of subsidence, the extent of the damage and whether repairs have been complete. Getting professional advice and assessments from a subsidence specialist such as Mainmark can help you assess the risks and prevent unexpected costs later on.