Guide
Resin injection underpinning cost: 2026 prices vs mass concrete
Updated
Resin injection is cheaper per metre and enormously less disruptive, but it is ground improvement, not a new foundation, and it is not right for every job. Here is the honest comparison.
How the two methods work
- Mass concrete (traditional) underpinning
- Excavating beneath the existing footing in a controlled sequence of pins and pouring concrete to found the wall at a deeper, stable level. Proven for over a century, works in almost all ground, produces a new structural foundation. Disruptive: weeks of excavation, spoil and access requirements. Typically £1,500–£2,600 per metre (typical 2026 quotes).
- Resin (geopolymer) injection
- Injecting expanding structural resin into the ground beneath the foundation through small drilled ports, compacting and strengthening the soil and, where specified, re-levelling the structure. No excavation, typically days on site, rooms stay usable. Typically £1,000–£1,800 per metre (typical 2026 quotes). It treats the ground rather than replacing the foundation.
Costs side by side
| Factor | Resin injection | Mass concrete |
|---|---|---|
| Typical cost per metre | £1,000–£1,800 | £1,500–£2,600 |
| Time on site | Days | Weeks |
| Disruption | Minimal, no excavation, house stays occupied | Major, trenches, spoil, sections of garden or floor up |
| What you get | Strengthened ground beneath the existing footing | A new, deeper structural foundation |
| Best suited to | Moderate movement where the cause is resolved and ground responds to compaction | Severe movement, deep instability, basements, ground resin cannot treat |
The honest caveats on resin
- Suitability is a ground question: resin needs soil that responds to compaction and a cause of movement that has been dealt with; it is not a fix for ongoing drainage leaks, active clay shrinkage still being driven by trees, or organic soils, get the site investigation before choosing the method.
- Per metre is not the whole comparison: some resin jobs need more metres treated than a targeted concrete scheme, so get both methods quoted on the same drawings.
- Design and sign-off still matter: whichever method, you want an engineer's specification, building control involvement and a guarantee you can show a future buyer, see how underpinning affects value.
- Insurers accept both where properly specified: on an insurance job the scheme design is between the engineer and the insurer, see the insurance route.
The right method is the one the ground investigation supports, not the one with the better brochure. Get both quoted for your job via the form, contractors will say quickly which method suits your soil.