Concrete Base for Shed, Garage or Garden Room
Looking for a perfectly level, long-lasting concrete base for your shed or outbuilding? At CJ Groundworks, we install robust, regulation-ready concrete bases for sheds, garages, garden offices, workshops and more — across Sussex, Surrey, and Kent.
With over 35 years in the groundworks industry, we create solid foundations that support structures of every size and purpose. Whether it’s a small garden shed or a large timber-framed building, we’ll build a base to match.
/ Our Services
Concrete Base Services
Shed & Garden Room Bases
- We install bespoke concrete shed bases for:
- Garden sheds & summerhouses
- Timber cabins & garden offices
- Workshops & home gyms
- Each base includes:
- Compacted Type 2 sub-base
- Damp-proof membrane
- Steel mesh reinforcement (where required)
- Smooth trowel or brush finish
Garage & Outbuilding Bases
- For larger, heavier structures, we offer:
- Thickened bases to support weight
- Insulated slab options
- Formwork & finishing to architectural spec
Bases for Modern Garden Buildings
- We regularly construct bases for:
- Garden rooms & outdoor studios
- Timber-framed annexes
- Gym cabins & playrooms
- Storage buildings & bike sheds
- No matter your project, we’ll tailor the size, finish and reinforcement to ensure long-term structural support and aesthetic alignment with your landscape.
/Planning
Key Considerations for Concrete Base Installation
When planning a base, we help you consider:
-
Ground conditions
Is excavation or levelling needed? -
Building load
Will it house equipment, furniture or vehicles? -
Insulation needs
Does the space need thermal performance? -
Finish preference
Smooth or brushed for anti-slip? -
Drainage & moisture control
Do you need a soakaway or water diversion?
Our site visits ensure every factor is addressed before work begins.
/ Our Mission
Why Choose CJ Groundworks?
35+ Years of Experience
A long-standing reputation built on expert workmanship.
In-House
Team
No subcontractors; we keep all trades under one roof.
Fully Insured &
Guaranteed
No subcontractors; we keep all trades under one roof.
Compliant &
Certified
All works carried out to UK building regs and environmental standards.
Local
Expertise
Proudly serving Sussex, Surrey & Kent.
/ Our Area
Locations We Cover
We install concrete bases across:
- Cranleigh
- Horsham
- Midhurst
- Petworth
- Pulborough
- All surrounding areas in Sussex, Surrey, and Kent
Get a Free Quote for Your Shed
or Garage Base
/ FAQs
Frequently Asked Questions
For most garden sheds, a thickness of 100mm is sufficient. Heavier structures like garages may need up to 150mm. We assess your requirements and recommend the right spec for strength and longevity.
A solid, level base is essential for structural integrity. Timber bearers placed on soft or uneven ground can warp or rot. A concrete shed base provides durability, moisture protection, and alignment.
It’s possible, but a poorly laid base can cause major problems later. We use the correct mix, formwork, compaction and finishing tools to deliver professional results. We also ensure it complies with Building Regs if needed.
Prices vary depending on size, ground condition and access. A small base might cost £300–£600, while larger or reinforced slabs cost more. We offer fixed-price quotes with no hidden fees.
Most bases can be completed in 1–2 days, weather permitting. The concrete should be left to cure for at least 24–48 hours before any structure is installed.
/Our Contact
Ready to break ground?
Get in touch with CJ Groundworks today to discuss your project and receive a free, no-obligation quotation. Our team is here to answer your questions and provide expert advice tailored to your needs.
Address
CJ Groundworks, Lower Batchelors, Emms Lane, Barns Green, West Sussex, RH13 0QH.
/Our Testimonials