Concrete Bases for Sheds, Garages and Garden Rooms
CJ Groundworks installs concrete bases for sheds, garages, garden rooms, workshops, home gyms and timber-framed outbuildings across Sussex, Surrey and Kent.
With more than 35 years of groundworks experience, our family-run team manages the preparation and installation from excavation and sub-base construction through to formwork, concrete placement and finishing.
Each base is planned around the proposed building, site levels, access, ground conditions, drainage and manufacturer requirements. You will receive a clear quotation setting out the agreed dimensions, specification and work included.
/ Our Services
Concrete Base Installation Services
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.
Shed & Garden Room Bases
We install concrete bases for:
- Garden sheds and summerhouses
- Garden rooms and offices
- Timber cabins
- Workshops and hobby rooms
- Home gyms
- Storage buildings
Depending on the agreed specification, the work can include:
- Excavation to the required formation level
- Removal or redistribution of excavated material
- Compacted granular sub-base
- Edge formwork
- Damp-proof membrane
- Steel reinforcement where specified
- Concrete placement and levelling
- Smooth, floated or brushed finish
- Preparation for drainage or service entries
We can work from the building manufacturer’s base plan or agree the dimensions and construction detail before quoting.
Garage & Outbuilding Bases
Garages, workshops and larger outbuildings usually require a more substantial base than a small garden shed.
Our work can include:
- Excavation and formation preparation
- Compacted sub-base construction
- Perimeter thickening or edge beams where specified
- Reinforcement to the agreed design
- Damp-proof membrane
- Insulation where required
- Service ducts and drainage penetrations
- Formwork and concrete placement
- Surface finishing suited to the intended use
Base depth, reinforcement and edge details will be agreed from the structural information, building supplier’s requirements or approved project drawings.
Bases for Modern Garden Buildings
We construct bases for modern garden buildings, including:
- Garden offices and studios
- Insulated garden rooms
- Timber-framed annexes
- Gyms and playrooms
- Larger storage buildings
- Bike stores and workshops
These structures may require precise finished dimensions, insulation, service entries and carefully controlled levels. We will review the supplier’s installation details before work starts and confirm the base dimensions, finished height and surface finish included in the quotation.
Where the building is close to the house, a boundary or an existing patio, we also consider access, drainage and how the completed base will meet the surrounding ground.
/Planning
Key Considerations for a Concrete Base Install
Before preparing the base, we review the proposed building and the conditions around it. Key considerations include:
- Building dimensions: The base must match the supplier’s required footprint and tolerances.
- Intended use: A light storage shed has different requirements from a garage, workshop or insulated annex.
- Ground conditions: Soft, filled, sloping or poorly drained ground may require additional excavation or preparation.
- Finished height: The base should sit at an appropriate level in relation to surrounding ground, paths and thresholds.
- Access: Machinery, materials and concrete must be able to reach the working area safely.
- Drainage: Surface water should be directed away from the building without creating problems elsewhere.
- Moisture and insulation: Damp-proofing and insulation requirements depend on the structure and its intended use.
- Services: Electricity, water, drainage or data ducts may need to pass through or beneath the base.
- Surface finish: The finish should suit the building, exposed areas and intended use.
We confirm the agreed dimensions and construction specification before concrete is ordered.
/ Our Mission
Why Choose CJ Groundworks for Your Concrete Base?
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
Request a Concrete Base Quote
Planning a shed, garage, garden room or outbuilding?
Call CJ Groundworks on 07881 757877 or send us the site postcode, proposed base dimensions and the building supplier’s plan where available.
We will review the requirements, discuss access and ground conditions, arrange a site visit where needed and provide a clear, no-obligation quotation.
/ FAQs
Frequently Asked Questions
For most sheds, 100mm is suitable. Heavier buildings such as garages may need 150mm. We’ll assess the requirements to ensure proper strength and durability.
Yes — a stable base is essential to prevent warping, sinking or moisture damage. A concrete shed base provides long-term support and weather resistance.
While possible, improper preparation can cause cracks or uneven levels. We use the correct mix, compaction, and reinforcement to ensure your base is perfect and compliant with UK Building Regs.
Costs depend on size, ground condition, and access. Smaller bases start from around £300–£600, with larger reinforced slabs priced accordingly. We provide transparent, fixed quotes with no hidden fees.
Most projects are completed within 1–2 days, with 24–48 hours required for curing 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
What clients say about us
/ From the blog
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