Generally suitable
Ground screws are generally suitable in:
- Grass
- Hardcore
- Clay
- Soil
- Chalk
- Sandstone
Foundation
Garden room foundations, planned with your building
The foundation supports the building above it, so it needs to be considered as part of the project from the start. Your site, chosen building and intended use all matter.
We offer base supply and installation across the Noah range. It is included with some ranges and a paid option with others, subject to the requirements of your project.
Choosing your range
What is included in each range?
Garden Buildings: base supply and installation are optional.
Garden Pods: base supply and installation are optional.
Garden Rooms: base supply and installation are optional.
Signature Garden Rooms: base supply and installation are included.
Granny Annexes: GSB foundation supply and installation, plus a steel chassis between the foundation and building, are included, subject to site checks.
An included base does not remove the need to assess the site. Check your quotation for the agreed foundation method, preparation and any additional work.
Specification & options
Ground screw bases for garden rooms
Ground screws support the building through a base frame, providing a level foundation without a poured concrete slab where the site is suitable.
We assess the ground, access and known underground services before agreeing the foundation. Unsuitable ground or buried obstructions may require a different approach.
How it works
How your ground screw base goes in
A ground screw base supports your building on screws driven into the ground, with a level base frame on top. There is no concrete to pour and nothing to leave to cure.
- 1
We check the site
We look at the ground, the access and where the building will sit. Tell us about any pipes, cables or drains you know of. We may use CAT scanning equipment too, and a scan before installation can be arranged at extra cost.
- 2
The screws go in
Each screw needs suitable ground to a depth of about 725mm. If we hit something unexpected, such as rock or old concrete, we will talk you through the options.
- 3
The frame is set level
A base frame is fixed to the screws and levelled, ready for your building. Granny Annexes add a steel chassis between the base and the building.
- 4
Your building goes on top
We install your building on the finished base. Leave 1ft of clear space all round for installation and future maintenance.
Your garden
Will a ground screw base work in my garden?
Needs another look
These can stop a screw going in:
- Buried concrete or old foundations
- Rock or rubble
- Tree roots
- Made ground or unknown structures
If we find them, we may change the base design or suggest a different foundation. Extra work can carry an extra charge, and where there is no practical solution we may not be able to install.
Slopes and drainage
The ground can fall by up to 12 inches across the base area, unless we agree otherwise in writing. On a steeper garden, the ground needs digging and levelling before we arrive.
Keep water draining away from the base. Standing water and waterlogged ground can affect any foundation.
Planning your base
A base matched to your building
Support for the whole building
A ground screw base carries the weight of the room and its contents into the ground. Each screw has a reserved payload of 600kg, so the 18 screws under a 20 x 10ft building can carry over 10,000kg, against roughly 2,000 to 3,000kg for the installed building.
Tell us about substantial storage, gym equipment or machinery so those loads can be considered alongside the room itself.
A base option to suit your project
Our base supply and installation are included with Signature and Granny Annexes, and optional on Garden Buildings, Pods and Garden Rooms. Annexes also include a steel chassis between the ground screw base and the building.
If you already have a base, we can check whether its size, condition and position suit the proposed building before you arrange any further work.
Your options
Our ground screw base or your own base?
You can choose our ground screw base or provide your own. If you lay your own, it needs to meet these requirements before our fitters arrive.
| Noah ground screw base | Your own base | |
|---|---|---|
| Installed by | Our team | You or your contractor |
| Concrete | None | A slab 4 to 6 inches deep, cured for at least 7 days, or a timber-framed base with bearers running the length of the building |
| Ground checks | Site assessment, with CAT scanning available | Your responsibility |
| Level and size | Set level by our team | Solid, completely level and no smaller than the building. Gravel or loose hardcore does not count as solid. |
| If it is not right on the day | We may adjust the design or suggest an alternative | It needs correcting before installation. Our fitters cannot wait on site while it is fixed. |
| Warranty | Checked by our team at installation; later ground movement is not covered | From whoever lays it |
| Price | Included with Signature and Granny Annexes; an option on Garden Buildings, Garden Pods and Garden Rooms | Arranged by you |
Online configurator
Is the base in the price?
On Granny Annexes our ground-screw base is included. On every other range, choose our base or your own and see the price change.
Common questions
Garden room foundation questions
Are foundations included in the building price?
Base supply and installation are included with Signature and Granny Annexes; annexes also include a steel chassis above the GSB foundation. Bases are optional for Garden Buildings, Pods and Garden Rooms. The quotation confirms site suitability and the agreed scope.
Can ground screws be used in every garden?
No. Suitability depends on the ground and project requirements. Hidden obstructions or unsuitable conditions can require a different approach.
Can I arrange my own base?
Yes, if it is level and solid, such as a concrete slab or paving. Choose your own base or our ground-screw base in the configurator. On Garden Buildings, Pods and Garden Rooms our base is an optional extra. On Signature it is included, and building on your own base takes half the standard ground-screw base rate off the price. We agree the base size and position with you.
Is foundation installation the same as site preparation?
They are different parts of the project. Check which preparation, clearance and other groundwork are included in your quotation and which remain your responsibility.
Does the base count towards the 2.5m height limit?
Our ground screw base sits at ground level, so on flat, level ground it does not add to the height of a 2.44m pent building. On a slope the base follows the lie of the land, and a canopy roof can change the overall height. Check with your local council that the building still falls under permitted development. Our planning guide explains more.
Is the ground screw base guaranteed?
Our team checks the base is installed correctly before your building goes on it. A ground screw base is not a civil groundworks foundation, so we cannot be responsible for ground movement after installation. Keep water draining away from the base to help it stay stable.
Can the base be moved once it is in?
Not without an extra charge. Once installation has started, the base cannot be repositioned, so confirm the position and mark it clearly before we arrive.
Guides and advice
Read more before you decide
How-to guide
Good garden room foundations and why they’re essential
Noah experts unpack what garden room foundations are and why a solid base for a garden room is essential in this complete guide.
Read the guide →
How-to guide
Garden room cost: compare ranges, features and optional extras
Real 2026 garden room prices by size and spec, plus how to design and price your own.
Read the guide →
Ideas and inspiration
Do I need garden room planning permission?
Learn garden room planning permission requirements, including when you need to apply and what to do before your garden room installation.
Read the guide →
Free 48-page brochure
Get the Free Garden Room Brochure in Your Inbox
Forty-eight pages of finished buildings, every range with sizes and from-prices, and plain explanations of cladding, insulation and electrics. Request the brochure by email. Our team may follow up to discuss your plans.
- 48 pages of garden rooms and real installs
- Every range with sizes and from-prices
- Cladding, insulation and electrics explained
- Emailed brochure, with follow-up from our team
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