Flat, level bases that drain properly and carry the load they were designed for: compacted sub-base, membrane, insulation, fixed reinforcement and a finish matched to what goes on top. Free site visit and quote.
A base is only as good as everything underneath it
A concrete base looks like the simplest job on a site and is one of the easiest to get wrong. The concrete is the last five per cent: what decides whether a slab stays flat, drains where it should and carries its load is the sub-base compaction, the membrane, the insulation, the reinforcement position and the cover over it, and the levels set before anyone opens a mixer.
We build bases for houses, garages, workshops, outbuildings, sheds and garden rooms, plus yards, hard standings, aprons and reinforced bases for tanks, plant and containers. Everything is formed, reinforced, poured and finished by the same team, working to the engineer's details where there is a design and to sensible construction standards where there is not.
Finishes are chosen for use rather than habit, power floated where a floor covering or a workshop follows, tamped or brushed outside where grip and drainage matter. Falls are set out so water runs off the slab rather than sitting in the middle of it.
What's included
Ground bearing slabs
Garage, outbuilding and shed bases
Reinforced bases for plant and tanks
Yards, hard standings and aprons
Power float and tamped finishes
Insulation and damp proof membranes
Who it's for
Homeowners adding a garage, workshop, garden room, shed or extension base
Self-builders needing a ground bearing floor slab to specification
Farms and businesses needing yards, hard standings and plant bases
Developers and builders subcontracting slabs across plots
Anyone with an existing base that is cracked, ponding or sinking
When it's needed
A new garage, outbuilding, garden room or extension needs a base
A house or annexe needs a ground bearing floor slab
A yard, parking area or hard standing is rutting, ponding or breaking up
A tank, container, generator or item of plant needs a designed base
An existing slab has cracked, dipped or was never laid on a proper sub-base
Why It Matters
What a badly built base does over time
Cracking and settlement
Poor compaction, no reinforcement or reinforcement in the wrong place means the slab cannot span soft spots. Cracks open, edges drop and, once a slab has cracked through, patching it is cosmetic rather than structural.
Water ponding in the middle
A slab laid flat, or with falls set the wrong way, holds water. Outside that means ice, moss and freeze-thaw damage; inside a garage or workshop it means standing water every time a wet vehicle comes in.
Damp coming up through the floor
A missing, torn or badly lapped damp proof membrane lets ground moisture through the slab. Floor coverings lift, timber decays, and the fix means taking up the finished floor to get at it.
Failing building regulations on habitable floors
A floor slab in a habitable building needs the right insulation and damp proofing. Getting that wrong is both a comfort and an energy problem, and it will hold up building control sign-off.
Corroding reinforcement
Steel with too little cover, or laid on the ground rather than on spacers, corrodes and expands. That spalls the concrete from within and shortens the life of the slab significantly.
A base that will not take the load
Domestic-thickness slabs under commercial traffic, plant or tanks rut, crack and break up at the edges. It is a lot cheaper to build for the real loading than to break out and start again.
Common mistakes we're asked to put right
Laying concrete straight onto soft ground or topsoil with no compacted sub-base
Skipping or tearing the damp proof membrane, or failing to lap it into the walls
Pushing mesh into wet concrete instead of fixing it on spacers at the specified height
Pouring a slab dead flat outside, so it never drains
Under-thickening a base for the vehicles or plant that will actually stand on it
Pouring in frost or hard sun with no protection or curing plan
Our Process
How the job runs, step by step
Every job follows the same order, so you always know what has happened and what comes next.
Step 1
Free site visit and use discussed
We establish what the base is for, what will stand or drive on it, where water needs to go, and what the ground and access are like. Free visit, fast quote.
Step 2
Specification and price agreed
Thickness, sub-base depth, membrane, insulation, reinforcement and finish set out, to the engineer's design where there is one - and priced fixed, cost-plus or labour-only. Stage payments, no deposit normally required.
Step 3
Excavate, set levels and form up
Ground excavated to formation, levels and falls set from a datum, shuttering set square and to line, with edges and thresholds worked out before anything is filled.
Step 4
Sub-base, membrane and insulation
Sub-base laid and compacted in layers, blinded, then the damp proof membrane laid, lapped, taped and dressed up into the walls, followed by insulation where the slab is heated or habitable.
Step 5
Reinforcement fixed and checked
Mesh or bar fixed, tied and set on spacers so the specified cover is maintained top and bottom, with laps and edge detail to the drawings. Checked before concrete is called off.
Step 6
Pour, level and finish
Concrete placed and compacted, levelled to the set falls, then finished as specified: power floated, tamped or brushed - with joints where the design requires them.
Step 7
Cure, verify and hand over
The slab is protected while it cures, levels and falls are checked against the set-out, and the base is handed over ready for the structure, floor covering or traffic it was built for.
What You Get
The difference this makes on your concrete bases & slabs job
Flat, level and square
Set out from a datum with shuttering to line, so walls, frames and garage doors sit properly on it.
Drains instead of ponding
Falls set out deliberately for external bases and aprons, so water leaves the slab and does not sit or ice up on it.
Dry floors
Membrane laid, lapped, taped and dressed into the walls, with insulation where the slab is habitable or heated.
Built for the real load
Thickness, sub-base and reinforcement matched to the vehicles, plant or structure that will actually use it, not to a standard domestic detail.
Reinforcement doing its job
Steel fixed on spacers with the specified cover, checked before the pour, so it carries load and does not corrode.
The right finish for the use
Power floated for garages, workshops and floor coverings; tamped or brushed outside where grip matters.
One team from dig to finish
Excavation, sub-base, drainage, steel, pour and finish under one point of contact, with no gaps between trades.
Fully insured work
£5m public liability, £10m employers' liability and Contractors' All Risks cover, with CPCS plant operation and SMSTS site management.
In Detail
Concrete bases and slabs in detail
Ground bearing floor slabs
A ground bearing slab carries the floor loads of a building directly into the ground. The build-up is excavation to formation, compacted sub-base in layers, sand blinding, damp proof membrane lapped and dressed into the wall damp proof course, rigid insulation where the building is heated, then the reinforced slab itself. Perimeter insulation limits cold bridging at the edges, and where underfloor heating is going in, pipe layout and screed or slab thickness are agreed before the pour rather than after.
Garage, outbuilding and garden room bases
These are the bases we are asked for most, and the details that matter are usually the ones people leave out: getting the base big enough to build off with the right overhang, setting the level so a garage door threshold works and water runs out rather than in, thickening the edge where a wall sits on it, and a finish suited to vehicles. A power floated finish suits garages and workshops; a brushed finish gives grip on an external apron or ramp.
Reinforced bases for plant, tanks and containers
Point loads and dynamic loads need designing, not estimating. Oil and water tanks, treatment plants, generators, biomass stores, containers, machinery and slurry-related structures all impose loads very different from a car. These bases get thicker sections, heavier reinforcement to the engineer's schedule, and often kickers, holding-down bolt positions or bunding cast in. Bolt positions and openings are set out and checked before the pour, because moving them afterwards means breaking out concrete.
Yards, hard standings and aprons
External concrete has to cope with weather, water and heavy wheels. Sub-base depth is set for the traffic, crossfalls take water to a channel drain, gully or defined discharge point, and edges are restrained or thickened where wheels will run over them. On farms and commercial yards we build slabs to take telehandlers, tractors and delivery lorries, with joints laid out to control cracking. Aprons between a building and the surrounding ground are set below threshold level with a fall away from the structure.
Materials, mixes and reinforcement
Specification is matched to duty and exposure:
Mix design, strength and slump specified for the use and the weather on the day
Air-entrained mixes where external concrete faces freeze-thaw exposure
Fabric mesh reinforcement for typical slabs, bar and cages where the engineer specifies
Fibre reinforcement where it suits the application and the specification allows
Correct cover maintained with spacers and chairs, checked before the pour
Compacted granular sub-base with sand blinding to protect the membrane
Membranes lapped, taped and dressed into wall damp proof courses
Rigid insulation, perimeter insulation and, where required, underfloor heating build-up
Finishes, joints and curing
Finish and jointing are part of the design. Power floating gives a hard, smooth surface for garages, workshops and floors receiving a covering; tamped and brushed finishes give grip outside; a float finish suits bases that will be screeded or tiled later. Movement, construction and day joints are set out to control where cracking happens rather than leaving it to chance, and slabs are cured and protected, kept from drying too fast in sun or wind, and protected against frost - because concrete that is not cured properly never reaches the strength it was mixed for.
Repairs, replacements and existing bases
We are often called to a base that has cracked, dipped or ponded. Sometimes there is a repair: cutting out and replacing a failed section, re-levelling and draining a yard, or forming a new apron to take water away. Often the cause is no sub-base, no membrane or no reinforcement, in which case breaking out and rebuilding is the only honest answer, and we will say so rather than take money for a patch that will fail in the same place.
Domestic versus commercial and agricultural
Domestic bases are about access, tidiness and getting the levels and thresholds right around a house people live in. Commercial and agricultural slabs are about loading, drainage, jointing and wear from heavy machinery, with more attention to falls and edge details. Developer work is about repeating a correct detail accurately across multiple plots. We work across all of them from Horningtops, across Cornwall and Devon as far as Exeter.
On Site
Concrete Bases & Slabs we have carried out
Photographs taken on our own sites across Cornwall and Devon.
Concrete Bases & Slabs questions we get asked most
If your question isn't here, ring Calum and ask, a straight answer costs nothing.
How much does a concrete base cost?
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It depends on the area, the thickness and reinforcement the use demands, the sub-base depth, access for concrete delivery and how much muck comes out. A garden room base and a reinforced yard slab are very different jobs. We look at it, then quote fixed price, cost-plus, or labour-only. Site visits and quotes are free.
How thick should a base be?
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It follows the loading and the ground, and on habitable buildings the engineer's design. A garden room base, a garage floor, a house floor slab and a yard taking a telehandler all need different thicknesses, sub-base depths and reinforcement. We specify it for what will actually stand and drive on it rather than defaulting to one detail.
How long before I can build on a new slab?
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Concrete is normally walkable within a day or so and ready to build off within a few days in typical conditions, but that depends on the mix, thickness and weather. We will tell you the realistic dates for your pour, and we protect and cure the slab in the meantime rather than rushing it.
Do you fit a damp proof membrane and insulation?
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Yes on any slab where it is needed. The membrane is laid on blinded sub-base, lapped, taped and dressed into the wall damp proof course, and rigid insulation goes in where the building is heated or habitable, along with perimeter insulation to limit cold bridging.
Can you make my existing base bigger or repair it?
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Sometimes. Extending or repairing works where the existing slab is sound, properly founded and thick enough; we can cut out and replace failed sections or form a new apron to fix drainage. Where the original has no sub-base, membrane or reinforcement, breaking out and rebuilding is the only lasting answer, and we will tell you that straight.
Why does my yard hold water, and can you fix it?
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Almost always because it was laid flat or with falls running the wrong way, and often with no defined discharge point. We can regrade and re-lay with proper crossfalls to a channel drain or gully, and deal with the drainage at the same time since we install that ourselves.
Can you pour a base for an oil tank, treatment plant or container?
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Yes. These get a designed base: thicker section, heavier reinforcement to the engineer's schedule, and holding-down bolt positions, kickers or bunding cast in as required. Bolt positions are set out and checked before the pour.
What finish will I get?
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Whatever suits the use. Power floated for garages, workshops and floors that will take a covering; tamped or brushed for external slabs, aprons and ramps where grip matters; float finish where a screed or tiles follow. We agree it before the pour so there is no surprise.
Can you work in winter?
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Yes, with the right precautions; we do not pour into frozen ground or leave fresh concrete unprotected against frost, and we use appropriate mixes and protection. If the weather genuinely means the pour should wait a day, we will tell you rather than pour and hope.
Which areas do you cover?
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All of Cornwall and Devon as far as Exeter, from our yard at Horningtops just outside Liskeard, Liskeard, Menheniot, Dobwalls, St Ive, Callington, Looe, Saltash, Torpoint, Bodmin, Launceston, Fowey, St Austell and Tavistock included.
Related Work
Services that usually go with this one
Most jobs cross more than one trade. Taking them together keeps the programme and the price tighter.
Get a free concrete bases & slabs quote from someone who's walked the ground
Calum will come out, look at the site and give you a straight price: fixed, cost-plus or labour-only, whichever suits the job. No deposit normally required, and stage payments as work is completed.
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