Twenty years ago, a property with a subsidence problem meant one thing: a digger in the front garden, weeks of disruption, and a six-figure bill if the engineers were thorough. Today there's a better option for most homes. Resin foundation injection can stabilise and re-level a settling property in 24 to 48 hours, with no excavation and no spoil to cart away.
What's actually happening underground
A two-part structural geopolymer resin is injected through pencil-thin tubes inserted alongside or beneath the existing footing. As the two components meet, they react and expand to many times their original volume. The expansion compresses the soft soil around it, fills voids, and provides controlled lift to the structure above. A surveyor with laser levels watches the property rise back to true, sometimes just millimetres at a time, until the geometry of the building is restored.
It's not magic. It's controlled engineering, and it works on the same principle as expanding foam, scaled up and engineered to carry building loads.
When resin is the right call
Resin suits properties where the bearing soil has weakened, dried out or developed voids, but the existing footing is still structurally sound. That covers most clay-shrinkage subsidence in Orpington and Sidcup, sunken slabs and driveways, settling extensions and conservatory bases, and warehouse or factory floors that have dropped from heavy point loads.
It's not the right call where the existing foundation itself has failed, where the load needs to be transferred to a much deeper stratum, or where the property is listed and any chemical introduction needs special consent. In those cases traditional underpinning is still the gold standard.
What it costs around Bromley
For a typical three-bedroom semi with one elevation showing subsidence, resin injection comes in between £4,000 and £12,000 including the structural survey and post-works monitoring. That's roughly half to a third of the cost of comparable underpinning, completed in a fraction of the time. A sunken driveway slab lift, by contrast, can start as low as £2,500. The specialists matched through this site quote per job, so the number you get is the number you pay.
What the day looks like
The crew arrives, sets out the injection grid against the engineer's drawing, drills the access ports and connects the pump. Injection itself takes a few hours per elevation, with laser monitors showing real-time lift. By late afternoon the ports are plugged, the area is swept down and the property is back in use. There's no muddy excavation to make good, no skip on the kerb for a week, and no need to move out.
If your property is showing the classic signs of subsidence and you want to know whether resin is the right answer, the place to start is a survey. Tell us a bit about the property and we'll match you with a specialist who works in your postcode and uses resin where it's appropriate.