How much did it cost to fix foundation subsidence in 2025

The average cost of fixing foundation subsidence in homes in 2023 was £14,000. What is the leading cause of subsidence?

It is caused by the ground and the soil beneath the foundations of a property sinking or collapsing. The cost of fixing subsidence will depend both on the severity and scale of the subsidence and the method used to stabilise and possibly re-lift the property and then strengthen the ground beneath the affected foundations.

This average cost of £14,000 is based on a 3-bed semi-detached house needing subsidence repair along a single perimeter wall. To get a better understanding of how the method of foundation subsidence repair affects the cost, we can look at using three different methods used to strengthen compromised ground:

• Mass concrete method
• Piling method
• Resin injection process

These three methods vary in approach, techniques and materials employed and, notably, costs.

The cost of underpinning a single wall in a 3-bed terrace using the mass concrete method would typically be around £13,000; for piling, this would be £23,000, and for resin injection, £11,000 on average.

In a larger property, such as a 4-Bed Detached house, the subsidence costs would rise considerably to an average of £21,000 for mass concrete, £35,500 for piling and £16,000 for the resin injection method.

In addition to these foundation subsidence repair costs, a further investment could be required to fix any damage caused to the home or the structure itself. The daily rate for tradespeople required, such as plumbers, builders, and drainage specialists, may need to be accounted for in the cost of repairing the property once the underpinning operation has been successfully carried out.

A structural engineer, costing around £70 an hour, could be needed for any underpinning project to ensure that the most suitable underpinning method is used and to generate any documentation required for planning permission or building control purposes. If the property has a party wall, then a party wall agreement may need to be drawn up to detail the subsidence work that will be carried out. The cost of this, plus the planning permission and building control fees, could add in the region of £1900 to the cost.

The most cost-effective method of fixing foundation subsidence will depend on the methods suitable to resolve the issue. If the structural engineer on the project decides that all three methods we have discussed so far could be used, then the modern method of resin injection would be the most cost-effective. This method also brings with it some additional advantages over the more traditional methods of underpinning.

The mass concrete method reinforces the foundations slowly by digging holes at appropriate places under the foundations and filling them with concrete. This method is suitable for shallow foundations only, and to ensure that the foundation is always supported, the addition of concrete is added one section at a time, so it is a slow process.

Piling is suitable to support deeper foundations. It requires skilled tradespeople and heavy machinery to drive the pipes into the ground that are then linked together by steel or concrete to produce strong support for the foundations. The presence of heavy machinery can make piling a very disruptive as well as an expensive underpinning process.

The modern resin injection method injects an expanding polyurethane resin into the ground under the foundations through strategically placed injection tubes. This resin fills any voids and compacts the soil. Once set, it provides solid support for the foundations. Further injection of resin can raise the foundations and return the part of the building affected by subsidence to its original level.

Compared to the more traditional methods of mass concrete and piling, resin injection is quicker, with a typical project to fix subsidence on property taking around a day to complete. As the resin delivery is via injection tubes, there is no need for digging or the use of heavy machinery, ensuring that disruption to the property is minimal by comparison with more traditional methods. Resin injection is a very precise computer-controlled process allowing the resin to be injected at key positions under the foundations at just the right amount to bring the foundations back to the original level.

Mainmark’s Teretek® resin injection solutions offer a fast, modern and economical way to fix foundation subsidence and re-level buildings in residential, industrial and commercial sectors. The technique is the modern alternative to traditional underpinning and uses an environmentally inert, non-intrusive process backed by our 20-year product warranty.

If you would like to learn more about the causes of subsidence, how to spot it and how modern resin injection systems can help fix it, please visit our subsidence repair page. If you have a subsidence issue, please contact us for an expert view of how we can help support your project and your building.