The cost of fixing subsidence will depend both on the severity and scale of the subsidence, on the type of property, and the method used to stabilise and strengthen the ground beneath. It will also reflect whether the fix is confined to stabilising the ground or whether a property is to be raised back up and returned to its original level.

There are the three main methods used to repair foundation subsidence.

• Mass Concrete: Requires a series of holes to be dug beneath the foundations which are then filled with concrete to provide additional structural support. It is a slow process because holes can only be dug one section at a time to ensure the building is always supported. Because it involves digging beneath the structure, this method is only suitable for shallow foundations.

• Piling: Involves driving steel supports down to firmer ground either beneath or adjacent to a building. Depending on the piling method used, individual piles can be linked by a steel or concrete beam to provide support for the foundations. This method can be used for deeper foundations but installation does require skilled tradespeople and the use of heavy machinery to drive in the supports. It can also be both messy and time consuming.

• Resin Injection: Uses a series of strategically placed tubes to inject an expanding polyurethane resin into the ground beneath the foundations. The resin fills any voids and compacts the soil. Once set, the resin will provide a solid support for the foundations. Additional resin can then be added to raise the foundations to return the subsided part of the building back to its original level. Compared to mass concrete and piling, resin injection can resolve subsidence issues a lot quicker without the need to dig or to use of heavy machinery. Resin is delivered directly to where it is required using an injection process that ensures the precise amount of resin is injected to stabilise the ground. The technique can also be used to raise the foundations back to their original level. The process usually takes one day to complete for a typical property in Ireland.

Costs

The approximate costs to fix subsidence occurring beneath a single external wall in Ireland in 2025 are:

3-bed terrace house

• €15,000 for mass concrete,

• € 27,000 for piling

• € 13,000 for resin injection

4-bed detached house

• € 24,000 for mass concrete

• € 40,000 for piling

• € 19,000 for resin injection

In addition to the cost of fixing the subsidence, homeowners should also budget for the cost of:

• A structural engineer to advise on the most appropriate underpinning method and to produce any documentation for planning or building control approval;

• A party wall surveyor may be required to deal with the requirements of The Land and Conveyancing Law Reform Act 2009, if the subsidence involves a party wall;

• Works to repair cracks and damage and to redecorate the home

Technologies

Teretek® – resin injection subsidence treatment

Teretek® is an engineered solution for re-levelling subsided residential homes using an expanding polyurethane resin. Teretek® can be described as keyhole surgery for homes. Small holes are drilled under the foundation to enable tubes to be inserted. These enable Mainmark’s proprietary, environmentally inert resin to be injected beneath the home's foundations to improve the stability of the ground, fill any voids and, ultimately, to re-level the home.

JOG computer-controlled grouting for subsidence treatment

JOG computer-controlled grouting is a multi-point injection technique. This technology typically uses cementitious grout to re-level structures, including residential homes. It can be used to effectively treat bay window subsidence as the cementitious grout is injected under the foundations of the bay, using computers to accurately control the injection amounts in the various predetermined locations.

If you have a subsidence issue, please contact us for an expert view of how we can help support your project and your building.