Ground Screw Foundations for London and the Home Counties
Concrete-free foundations for garden rooms, extensions, decking and outdoor structures. Installed in a day. No digging, no curing time, no mess.
Fully insured · Engineer backed design · Most installs in 1 day · 25 year structural guarantee
For Garden Room Builders, Architects and Contractors
We work as your sub-contracted foundation specialist across London and the Home Counties — supplying and installing ground screw foundations on your projects, on your timeline.You quote the build. We handle the foundation. Your client gets a faster, cleaner project; you keep the foundation margin without the labour, the spoil removal, or the curing delays.
What we offer trade buyers
Sub-contracted install — turn up, install, sign off. We work to your spec or design with you.
Engineering and design support — load calculations, screw specification and structural sign-off included.
Reliable lead times — most installs scheduled within 2–3 weeks of order.
Trade pricing — volume discount on multi-job arrangements.
One-day install on most projects — your build team on site the next morning.
Full insurance — £10m public liability, £10m employer's liability, contractors all risk.
Documentation included — torque readings, load test reports, building control sign-off paperwork.
Foundations Without the Concrete
Planning a garden room, decking, hot tub or extension? Ground screws are a faster, cleaner alternative to concrete. We come in, install your foundation in a day, and your builder is ready to work the next morning.
We install for:
Garden rooms and sheds
Garden office, log cabins and summer houses
Hot tub bases and decking
Pergolas, outdoor kitchens and pavilions
Extension foundations (especially where access is restricted)
Outbuildings near protected trees (TPO sites)
Why homeowners choose ground screws:
Most foundations installed in a single day
Cost effective alternative to concrete
No digging, no spoil, no skip needed
No 28-day concrete cure — your builder starts immediately
Works on slopes, soft ground, and tight access sites
Lower carbon footprint than concrete
Easily removable if you change your mind in years to come
What are ground screws?
Ground screws (also called screw piles or helical piles) are galvanised steel foundations driven into the ground using hydraulic equipment. Each screw transfers the load of your structure deep into stable soil — typically 1.2 to 3 metres down — locking in place using helical blades that resist both downward force and uplift.The result is a foundation system that's quicker, cleaner, and more flexible than concrete, with load capacities tested up to 150kN per screw.
| Concrete Disadvantages | Ground Screw Advantages |
|---|---|
| 2 - 3 days install + 28 days cure | 1 day install |
| Extensive excavation | No excavation |
| Significant mess | Minimal mess |
| More costly / complex on sloping sites | Straightforward - minimal additional cost |
| Compliance issues near trees & roots | Usually not an issue |
| High carbon footprint | 50% lower than concrete |
Why us?
| Engineered, not improvised | Local to London and the Home Counties |
|---|---|
| Foundations designed and signed off by structural engineers with over a decade of experience installing helical pile systems on commercial scale projects. That commercial pedigree comes to you on every domestic install. | We cover Hertfordshire, Essex, Bedfordshire, Buckinghamshire, Cambridgeshire and the whole of Greater London. Most postcodes can be surveyed within a week. |
| Fully insured and guaranteed | No surprises on price |
|---|---|
| £10m public and employers liability / contractors all risk cover. Optional 10 year insurance backed structural guarantee on every install. | We quote a fixed price after a thorough free site survey. Our experience ensures there will be no unwelcome surprises. |
Recent Installations
Ground screw and steel frame for new build house in Hertfordshire.
Ground screws installed for extension in Surrey.
Ground screws being installed for small housing development in Essex.
FAQ's
Do I need planning permission for ground screws?
Ground screws themselves don't need permission. The structure you're building on top might — that depends on its size, height, and location. We can advise on the foundation; your architect or builder will handle planning.
How long does installation take?
Most domestic projects are installed in a single day. Larger jobs take 1–2 days.
What loads can ground screws support?
Anywhere from a small garden shed up to a multi-room modular building. Each screw is rated up to 150kN. We calculate the screw count and length based on your specific build.
Can I use ground screws near a protected tree (TPO)?
Yes — and they're often the only legally compliant option. Because there's no excavation, screws don't disturb root systems. We've worked on dozens of TPO sites.
What's the warranty?
All our screws come with a 25-year structural guarantee from the manufacturer. We also offer an optional 10-year insurance-backed guarantee on the install itself.
How do you price a job?
We charge a fixed price per project, based on the screw count and length your build needs. Most garden room foundations come in between £1,800 and £3,200 fitted, depending on screw count and access. We'll give you a fixed quote after a free site survey.
Do you work with garden room companies on a trade basis?
Yes — this is a major part of what we do. We offer trade pricing, design support, and reliable lead times for repeat trade buyers. Get in touch to set up a trade account.
What happens if you hit rock or services?
We carry out a CAT scan before any install to locate underground services. If we hit obstructions, we relocate the screw — that flexibility is one of the main advantages of screws over concrete. No surprise extras.
Get a Quote
Capital Ground Screws | © 2026 [Privacy policy] [Terms]