What are the benefits of underpinning and resin underpinning?

Underpinning strengthens the building’s foundations and stabilises the structure’s integrity. It can, however, take weeks or months to complete the work. Piled underpinning for example, involves removing internal floors and installing a grid of steel-cased piles, which would then be filled with concrete to ensure the structure has a stable foundation. That means homeowners will need to vacate the property while works are underway.

The work involved in resin injection underpinning creates very little disruption and no heavy machinery is required, which means it can be usually done whilst the building is occupied. A number of small-bore injection tubes are strategically placed to deliver the expanding polyurethane resin mix into the ground at the right points to strengthen the ground, stabilise the foundations and help to re-level the building.

Resin underpinning is also less expensive. The estimated cost of traditional types of underpinning for example, is up to £1,500 per linear metre (LM) for mass concrete underpinning and up to £2,600 per (LM) for piled underpinning. The subsidence resin injection cost is between £800-£1,500 per LM, making it a more cost-effective solution.

When should you use resin injection underpinning over traditional methods?

Both traditional underpinning methods and resin injection can resolve foundation issues, but it’s important to consider the circumstances of the property and the subsidence risk.

If a property has significant foundation issues, requires major structural support, or if it’s being extended to add another level, traditional types of underpinning work best. In cases where there are smaller subsidence issues, there is a limited time frame or you’re unable to get homeowners out of their property, resin injection is the ideal method.

It's also suitable in areas where there is limited working space, both inside the property and access to it. Traditional underpinning requires lots of machinery and equipment including skips. With resin injection, however, all that is needed is a medium truck and van.

Mainmark’s Teretek® geopolymer resin injection was used to strengthen the grounds beneath several Grade II listed bungalows that were part of Birmingham City Council’s social housing refurbishment project. Due to the time limitations of the project, remediation works had to be completed swiftly. A ground investigation looked into the causes of the subsidence and resin injection proved to be the preferred method. Despite the potential presence of high levels of ground water below the bungalows, this was not an issue was for the geopolymer resin as it’s hydrophobic in nature.

Our Teretek® engineered resin injection is environmentally inert making it suitable for use across a wide range of buildings and soil types.

If you’re considering your options, or would like some more guidance about which method is most suitable, please get in touch and we will offer you the right support for your project.