How much does subsidence devalue a property?

Anyone may be able to guess that when a house sinks, there's probably something seriously wrong.

Subsidence can be a really serious issue when it comes to property. If left unresolved, it can cause real damage to the entire structure of a building, not to mention the cost of repairs involved, and the risk to the future saleability of the property.

If you're trying to sell a house with subsidence, you're probably going to have to accept a lower house price, especially if your prospective buyers need to manage the repairs once the sale has gone through.

But how much does subsidence devalue a property exactly? And how much does it cost to repair a house with subsidence?

In this article, we'll take you through everything you need to know about subsidence, from how much subsidence devalues your home, to how you can resolve the issues to make it more attractive to potential buyers.

What is a house with subsidence?

A house with subsidence means the ground beneath it is sinking, which in turn affects the property's foundations (including extensions). Subsidence can be minor or major, but the more serious it is, the more the structural integrity of the property is at risk.

Ongoing subsidence versus historical subsidence

Subsidence can also be referred to as ongoing subsidence or historical subsidence (or historic subsidence). Ongoing subsidence means the subsiding soil beneath the house is still affecting the property. With historic subsidence, the ground has stopped subsiding, which means it's probably a lot less serious.

The signs of a house with subsidence

There are a number of signs that will indicate if the ground underneath a house is suffering from ongoing or historical subsidence, including:

• Leaning walls.
• Subsidence cracks in the walls.
• Doors and windows that don't fit properly.
• Sloping floors.

The causes of subsidence

House subsidence occurs for a number of different reasons, such as:

The type of ground beneath the property

Subsidence issues can be caused by the type of ground beneath a property's foundations. It will often occur in clay soil areas because it's a less stable type of soil. Clay soil will absorb water and expand in wet weather before drying out and contracting in dry weather, which can cause issues for the foundations of a property. Sandy or silty soils can also cause a subsidence problem.

Flooding

Flooding is another common cause of subsidence. This could be from excess rain, a broken or leaking pipe in a sewer, or long periods of dry weather that lead to a fall in the water table where the ground dries out and compacts.

The structural adequacy of the property

A property with structural issues or construction problems may suffer from subsidence. For example, if the building land hasn't been prepared properly, or the foundations aren't strong enough to support the weight of the property, there's an increased risk of subsidence.

Underground mining

If the ground in an area has a mining history, (such as underground coal mining or mining for other minerals) there's a chance your house will suffer from subsidence.

Large trees

Large trees, tree roots and plants that take moisture from the ground can sometimes be a cause of subsidence.

Underpinning

Repairing subsidence might seem like a daunting task, but here are various underpinning methods you can use to fix the issue.

Mass concrete underpinning method

A mass concrete fill is usually the cheapest way to repair subsidence. This method involves removing the existing soil from underneath the property and replacing it with concrete. It may be needed under more than one wall.

Piled underpinning

Piled underpinning (or mini piled underpinning) has become a popular method to repair subsidence. It's one of the quickest methods and doesn't need as much concrete and spoil disposal, making it much better for the environment. Piled underpinning can also provide stronger underpinning in poorer quality soils.

This method refers to inserting piles (metal or concrete shafts) into the ground to distribute the load of a structure down to a secure sub-surface layer.

Beam and base method

The beam and base method of underpinning is more technically advanced than mass concrete underpinning. A reinforced concrete beam is built below, above, or as a replacement for the existing footing, which then transfers the load of the building to mass concrete bases.

Soil strengthening

Soil strengthening like grout injection or resin injection is another way to underpin a house with subsidence.

Subsidence repairs

Once you're repaired the subsidence itself, you'll also need to repair any damage caused by the subsidence. This includes any aesthetic or structural issues like cracks in the walls or damage to the structural integrity of the building.

Seeking advice from structural engineers

If you're dealing with a house with subsidence, whether it's trying to sell a house with subsidence or trying to repair damage caused by subsidence issues, it's really important to seek advice from a surveyor or structural engineer.

They'll be able to offer the best advice to help you move forward, whether that's offering the most cost-effective way to repair the damage, the amount of underpinning required, or how best to sell the property.

Does underpinning devalue property?

While subsidence often devalues a property by quite a significant amount, underpinning can seriously help bring the property value back up.

If a house with subsidence has gone through underpinning, it will be historical subsidence rather than ongoing subsidence, which means the value should only be decreased by about 5%.

Time can also be another factor that affects the value of an underpinned house. Specifically, if the underpinning was done more recently, potential buyers might be less willing to put in an offer because the house will still be undergoing monitors for post-repairs.

There's less certainty that the underpinning was successful long-term, and prospective buyers want to be assured their house is structurally sound.

Insurance premiums and excess fees are also much more likely to be higher if the underpinning was only carried out recently. This may affect how much potential buyers are willing to offer.

Why does subsidence affect house price?

Subsidence issues may impact property value for a number of reasons.

Subsidence issues can cause serious obstacles during a house sale. A lot of potential buyers won't even consider a house with subsidence issues, and those who do consider it will usually expect a reduced asking price to cover the cost to make repairs. Most potential buyers will never be prepared to pay the full market value of the property.

One of the biggest reasons subsidence devalues a property is that it often makes the property unmortgageable as a lot of mortgage lenders won't approve a house with subsidence.

Read more about mortgage affordability checks here.

This usually means that a house with subsidence is only available to cash buyers like property developers. A cash buying company will usually expect to pay less than the full property value.

You can find out more about cash buyers in one of our previous blogs.

How much does subsidence devalue a property?

How much subsidence issues will devalue a property depend on how serious they are and how much it will cost to repair. On average, subsidence will devalue a property by about 20-25%.

Subsidence will devalue a property by at least the cost of it takes to fix the issues, so which underpinning method you use will factor into the final overall amount. You also need to factor in the cost of repairing any further damage caused by the subsidence.

For example, if your home has a value of £400,000 and the subsidence repairs cost £40,000, this devalues the property by at least the costs involved to fix these issues (in this case £40,000), making the subsidence devalue amount 10%.

However, some cases will devalue properties by much more than this. Severe subsidence might make a property completely unsaleable, which means the value could be decreased by the entire 100%.

Minor subsidence issues

On the other hand, minor subsidence (often historical subsidence) may not devalue a property much at all, especially if the damage caused isn't very big.

If the house has been professionally diagnosed and properly fixed and underpinned by a structural engineer, the subsidence shouldn't devalue the property by much.

How much does underpinning cost?

The cost of rectifying subsidence via underpinning will depend on how much work is needed and the level of underpinning required. A surveyor will suggest subsidence repairs that best suit your needs.

Piling is the most expensive type of underpinning as it's only used for deep foundations, while mass concrete fill and beam and base tend to be cheaper.

Does house insurance cover subsidence?

Most house insurance policies cover subsidence if the property has never had any previous subsidence issues.

Most buildings insurance policies also cover the cost of fixing any damage caused by subsidence as part of a subsidence claim. Depending on which insurance company you work with, there may be a large insurance excess to pay.

Subsidence covered by specialist insurance packages

For certain subsidence claims, or if you've had past insurance claims for subsidence, you may have to seek a specialist insurance package. For example, if:

• The property is at risk of riverbank or coastal erosion.
• There's damage to the land the property sits on.
• You want to go ahead with an underpinning method.

Specialist insurance packages should cover the costs of all damage, reparations, as well as any alternative accommodation you need while the work is being carried out.

Selling a house with subsidence

If you want to sell a house with subsidence or subsidence history, it's important to have certain expectations, especially if you're trying to find someone who isn't a cash buyer. Most importantly, you should expect a lower asking price for your property to help potential buyers cover the cost of any repairs needed.

Assess the property

Before you list your house, you should get a survey from a conveyancer, or get the building assessed from a structural engineer. This will help to measure how bad the damage is and how much structural work and repairs are needed. You'll then need to share this information for potential buyers and estate agents.

Carry out repairs

It's usually better to carry out any necessary repairs (not just subsidence, but other major repairs too) before listing the property. This will increase your chances of getting a price you're happy with, whilst also making it more attractive to potential buyers.

And of course, the more interest you have in your property, the more likely you are to get full market value in your house sale!

Declare subsidence

If you're selling a house with subsidence, you have a legal responsibility to be completely transparent and honest about the issues that come with the house. This means including every detail in the property information form, as well as providing all the correct documentation to your potential buyers.

You should also include the results from your survey as this will help manage the potential buyers' expectations and build trust.

If you lie to your potential buyers, not only could this seriously lower their asking price, they might decide to pull out of the property sale altogether - which takes you back to square one. You may also face legal consequences if you're deliberately misleading or provide false information to prospective buyers during a property sail.

Budget accordingly

As with any house sale, it's really important to set realistic expectations for your budgeting, especially if you need to make allowance for subsidence repairs and a lower asking price.

Remember to also factor in legal fees, conveyancing fees, and house insurance fees. You'll also need to pay estate agent fees, which will vary depending on which estate agent you decide to work with.

Find the right estate agent

Finding the right estate agent is really important when selling a house with subsidence (or any house sale for that matter!).

The cheapest available option isn't always the best one. In fact, you'll need an estate agent with plenty of expertise and local knowledge to help inform and guide you during your selling journey.

Summary: Stay on top of your subsidence!

Ultimately, subsidence can seriously devalue your property, even more so if you fail to solve the issues as quickly as possible.

Not only do potential buyers not want to risk investing in somewhere that can have some serious structural problems, but the cost of damage repairs can rack up very quickly. That's why underpinning to repair the damage is really important - it makes your property much more attractive to potential buyers.

We've said it once, we'll say it again. If you're thinking about selling a property with subsidence, finding the right estate agent is essential. Using impartial, performance-based data, our Estate Agent Comparison Tool lets homeowners compare the top performing estate agents in their local area.

You can explore the number of live listings, purchase prices versus asking price, and how long it takes to get the sale through. Check it out here and start your selling journey off on the right foot.