Groundworks in Aylesbury
Bases, excavation, sub-base preparation and drainage — the work that sits underneath everything else. If you're buying a garden room, a shed or a hot tub, this is the part that decides whether it's still level in five years.
Concrete base (shed, garden room, hot tub)
£110–£190 / m²
Reinforced where the load requires it. Minimum charges apply on small bases.
Excavation and sub-base preparation
£45–£80 / m²
Includes dig, membrane, MOT Type 1 in compacted layers and cart-away.
Drainage, soakaways and land drains are priced per job once we've seen where the water currently goes. How our pricing works →
If you're working to a budget
Groundworks is the part we would never advise economising on, because everything above it depends on it. If the budget is tight, spend it here and choose a cheaper surface on top — gravel or tarmac — rather than the other way round.
What we build
- Hot tub bases specified for the filled load
- Garden room and outbuilding bases to the supplier's spec
- Shed and greenhouse bases
- Reinforced concrete slabs and rafts
- Excavation, levels and cart-away
- Sub-base preparation for other trades
- Land drainage, soakaways and channel drains
- Retaining structures and level changes
When you need a proper base — and when you don't
When it's the right choice
- Anything holding water: hot tubs, swim spas, large planters. A filled tub is around two tonnes on a small footprint and needs a slab designed for it.
- Any manufactured building — garden room, office, large shed. They arrive square and need a base level within a few millimetres.
- Ground that's been made up, backfilled or disturbed by building work. It hasn't consolidated and it will settle.
- A garden that puddles or runs towards the house. Fix the water before you spend money on a surface.
When it isn't — say so and pick something else
- A small plastic or timber shed on firm, level ground — bearers on a compacted, well-drained base are often enough, and we'll tell you that rather than sell you concrete.
- A lightweight greenhouse where a perimeter base and a gravel floor does the job for a fraction of the cost.
- A temporary structure you'll move in a season. A slab is permanent and taking it out again costs money.
- A base poured in the wrong place. If you haven't confirmed the exact building footprint and door position with the supplier, wait. Recutting a slab is expensive.
How we build a base
Dig out to a formation that's firm, not just deep — soft spots get taken out and replaced rather than bridged over. Separation membrane, then MOT Type 1 laid and compacted in layers with a plate or a roller, not tipped in one lift and driven over.
Concrete slabs are formed, poured to a specified thickness, reinforced with mesh where the load or the span calls for it, and finished level. Where a base has to shed water, we build in a fall and take the water somewhere it can go.
Every base is photographed before it's covered, so you have a record of what's under your building. See the full build sequence →
Groundwork detail from our own jobs
Five-year workmanship guarantee, sub-base included
Most guarantees quietly stop at the surface. Ours covers the part you can't see: the excavation depth, the membrane, the compacted sub-base, the falls and the edge restraints. If the ground work moves, we come back and put it right.
A fixed price before anyone starts digging
We measure, agree the build-up in writing and give you one price. It doesn't move unless you change what you've asked for, or unless we open the ground and find something nobody could have known was there — in which case we stop, show you, and agree the cost with you before we carry on.
Common questions about groundworks
How heavy is a filled hot tub really?
Far heavier than people assume. A typical six-person tub holds well over a tonne of water on its own; add the shell, the cabinet and the people in it and a common all-up figure is around two tonnes concentrated on a footprint of roughly four square metres. That is not a paving slab load. It needs a base designed for it — normally a reinforced concrete slab on a compacted sub-base — or the tub tilts, the shell stresses and the cabinet racks.
Can a hot tub sit on an existing patio?
Sometimes, but only if we know how that patio was built, and usually we don't. Bedded slabs on a thin base will settle unevenly under a point load. We'd rather dig a trial hole and see the build-up than take a guess, and if the existing patio isn't up to it we'll say so and price a slab.
What base does a garden room need?
Either a reinforced concrete raft or a beam-and-pad arrangement, sized to the building and the ground. It has to be level within a few millimetres across the whole footprint, because the building is manufactured square and will not forgive a twist. Most garden room suppliers publish a base specification — send it to us and we'll build to it.
Do you take the spoil away?
Yes, and it's in the fixed price. Excavation produces a surprising volume — a 40m² dig at 250mm is roughly ten tonnes of material. Anyone quoting without accounting for cart-away is either going to add it later or leave it in a heap at the end of your garden.
Can you fix a garden that holds water?
Often, yes. It usually comes down to falls, compaction and where the water is supposed to go. Solutions range from land drainage and a soakaway to regrading the levels. What we won't do is lay a surface over standing water and call it solved.
Do you do the groundworks and then someone else builds on top?
Happily. Plenty of our groundworks jobs are bases for somebody else's garden room, shed, greenhouse or outbuilding. We'll build to their published specification and photograph the base before it's covered.
Towns we cover
We're based in Aylesbury and work about ten miles around it.
- Aylesbury
- Bierton
- Stoke Mandeville
- Weston Turville
- Aston Clinton
- Wendover
- Waddesdon
- Wingrave
- Whitchurch
- Quainton
- Wing
- Haddenham