Subsidence repair costs

Hearing that your home has subsidence is worrying. To help you take positive action and plan your budget, we've put together this guide on subsidence repair costs.

When it comes to property damage, you'll most likely have heard of the infamous subsidence. But what are realistic subsidence repair costs?

We've put together this guide to help you understand what options are available for repairing subsidence and why it's so important to do so.

How much are subsidence repair costs?

For a breakdown of each cost, we spoke to the online estimators at My Build Estimate – a professional estimating company monitored by the Royal Institution of Chartered Surveyors (RICS). This guide features the estimated subsidence repair costs they provided.

When putting together this guide and estimating the cost of repairing subsidence, we have considered the following:

• These works are very complex and require a site survey

• No allowance for improving internal areas, e.g. decorating or skimming

• No allowance for improving external areas, e.g. paving etc

With these allowances in mind, the price of subsidence repair can be costly due to the extensive works that need to be completed.

To add extra support to a home, this is usually done through the technique of underpinning. Through this approach, the average cost of fixing subsidence in the UK is £12,500.

How much does it cost to sort subsidence in a property?

If you're budgeting to repair subsidence, be sure to consider the above factors and the four methods available. Here are some figures for the average cost to repair subsidence in the UK:

• Mass concrete method - £400 per m²

• Resin injector method - £550per m²

• Beam and base method - £700per m²

• Piling - £1,000 per pile

What is subsidence?

When the earth beneath your home starts to sink, this is what's known as 'subsidence'. The worse the subsidence is, the more this will affect the structural integrity of the building.

In essence, subsidence refers to the ground beneath your home and your foundations sinking or collapsing.

Subsidence can be caused by seasonal changes to soil, clay, and trees, with older homes more at risk due to shallow foundations.

Another cause of subsidence is leaking water mains and drains saturating the soil, making it soft and compromising the support of your property.

Why repair subsidence?

You may wish to repair subsidence to stop your house from sinking or to better support your foundations and ensure your home is safe and secure.

If your neighbours are having subsidence issues, you may even choose to take a proactive stance and increase the support structure of your house before a problem occurs.

Another reason to tackle subsidence head-on is if you're adding an extension, another floor, or a basement to your home.

In this case, you may wish to add extra support to your home foundations.

If you're considering adding an extension, please see our home extension cost guide to help plan for this work.

What is underpinning?

The usual method of treating subsidence, underpinning, is the process of adding extra support to the foundations of your home and preventing it from sinking.

Underpinning can be used to repair subsidence or to proactively increase the structural integrity of a building.

This is particularly useful if you are adding an extension or if your neighbours are having subsidence issues.

Types of underpinning

There are four main types of underpinning:

1. Piling method

Requiring a specialist type of equipment, piling allows foundations to go much deeper. It is generally the most expensive option but is great when the ground has varied conditions.

2. Mass concrete method

Probably the most commonly used method of underpinning, the mass concrete method involves pouring concrete into carefully positioned holes surrounding the home.

It's highly cost-effective and eliminates the need to remove the current foundations. Despite its benefits, this method can be time-consuming.

3. Resin injector method

Using a combination of hardener and glue, the substance is injected into small incisions above the foundations of the building.

A reaction then occurs causing the fluid to expand, fill cracks, and compact the earth. This method offers quick results.

4. Beam and base method

This method involves supporting and strengthening the building with concrete beams. It can be more effective than the mass concrete method but has a high subsidence repair cost.

To help you find the right subsidence solution...

We spoke with a Checkatrade member who specialises in ground engineering:

“Resin injection is now the go-to solution for subsidence of any size. It's an effective and permanent method to stabilise buildings affected by structural movement. Resin injection takes a day to implement and homeowners don't need to move out, rather than weeks or months of underpinning and piling.”

How long does underpinning take?

It is difficult to accurately calculate the time underpinning will take due to the wide number of variables.

The timescale is impacted by the age of the property, the type of underpinning used, and whether extra tradespeople are required, e.g. structural engineers.

On average underpinning can take between 3 – 6 weeks.

Factors affecting house subsidence repair costs

So, how much does it cost to fix subsidence? The total cost of fixing subsidence will be affected by several factors.

Here are some of the most important factors to consider when planning your budget:

• Underpinning method – Each method has a different cost to fix subsidence, based on the materials and specialist equipment required

• Severity of subsidence – The more complex the subsidence repair is, the greater the total cost will be

• Size of house – Larger houses cover more ground so underpinning will cost more than smaller properties

• Number of floors in the building – Homes with multiple floors are at greater risk of subsidence and require more support, which means higher repair costs

• Party wall agreements– When subsidence affects a neighbouring property that you share a wall with then you'll need a party wall agreement, which can cost around £1,800

• Number of professionals needed – You'll pay more if you need help from numerous tradespeople, such as structural engineers, plumbers, plasterers, decorators, or tree surgeons

Contact or pay a trade through Checkatrade and you’re covered by our 12-month guarantee of up to £1,000*

* Eligibility and T&Cs apply

Useful subsidence repair checklist

• Discovering your house has subsidence can be scary, however, there are many options to repair this

• Underpinning is the main way of tackling subsidence; there are four different types of underpinning

• You may need planning permission and a party wall agreement in place before dealing with subsidence

• We recommend you hire a professional to repair subsidence as this is a complex and difficult job

FAQs

What are the signs of subsidence?

Spotting the signs of subsidence and tackling it quickly can mean huge savings on the cost of fixing subsidence.

Warning signs of subsidence are cracks internally or externally, wallpaper wrinkling, neighbours having a subsidence issue, doors and windows not closing properly, uneven floors, and warped walls.

How do party wall agreements affect underpinning?

Before undertaking subsidence repairs on homes that share walls, you must serve notice and gain the consent of your neighbour with a written agreement.

On average, a party wall agreement costs around £1,800.

Will home insurance cover the cost of repairing subsidence?

Whether or not your home insurance will cover subsidence repair costs depends on the type of cover you have and the current extent of subsidence in your home.

You must talk to your insurance provider before underpinning begins so they can approve the method you are using.

You will usually have to pay an excess when you make an insurance claim and you should ensure you submit evidence such as photographs.

Do I need planning permission when underpinning my home?

You should always check with a professional whether or not you need planning permission to make structural changes to your home. You will likely need to obtain this before underpinning is carried out.

Can I prevent subsidence?

Unfortunately, in many circumstances, it's not possible to prevent subsidence. There are several things you can do to reduce the risk of subsidence, such as:

• Removing trees that are close to your home

• Checking with neighbours about any issues they have

• Proactively reinforcing old properties can help reduce the risk

Can a house with subsidence be repaired?

Yes, in most cases there are multiple ways to deal with the damage caused by subsidence. Whether it's using mass concrete, piling, or other underpinning approaches, help is available.

To understand the options, we recommend speaking to local structural engineers to get their professional advice and guidance.

How much is my house worth with subsidence?

The effect of subsidence on your property price will depend on whether it's ongoing subsidence or historical (with no signs of resurgence).

If your property is suffering from ongoing subsidence then you can expect it to be worth roughly 20-25% less than the current market value.

For historical subsidence that shows no signs of being active, it potentially won't affect your property price at all.

How long is subsidence work guaranteed for?

With subsidence, it's often difficult to get a guarantee on repair work – based on the unpredictable nature of subsidence.

That said, some subsidence repair companies will offer 10-year guarantees on their work. This is becoming more common with modern subsidence solutions.

Can you permanently fix subsidence?

That depends on the cause of the subsidence. For example, if a tree has been identified as the cause and you remove the tree, this potentially permanently fixes the problem.

For other more major subsidence, there can be more widespread causes that can't be permanently fixed.

Speak to local subsidence experts to find out what solutions are appropriate for your property. They'll be able to tell you how long any subsidence repair work will last.

Do houses fall down with subsidence?

If left unresolved, subsidence can cause major structural damage to a property.

And, yes, it's not unheard of that properties with major subsidence can 'fall down'. In other words, their foundations sink, which then compromises the structural integrity of the building.

Can I repair subsidence myself?

Repairing subsidence is not a quick and easy job. In short, you should not attempt to repair subsidence yourself unless you are properly qualified.

Underpinning is challenging and, if done incorrectly, the structural integrity of your home and the safety of the inhabitants are at risk.

There are also strict building regulations and legal requirements surrounding underpinning and it is wise to hire a structural engineer to monitor the process.

The average hourly rate of a structural engineer is £100.

To find a local, reputable, tradesperson in your area and get a personalised subsidence repair quote use our free search feature.