Groundworks in Coventry
Everything above ground depends on this stage, and it is the one part of a build nobody ever sees again. Which is exactly why it gets inspected before it is covered up.
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Groundworks in Coventry covers excavation, foundations, drainage and concrete for extensions, garages and new builds. Foundation depth and type are set by the ground conditions, the loads and the proximity of trees and drains, and Building Control inspects the excavation before any concrete is poured. Drainage connections, soakaways and below-ground pipework are set out and tested as part of the same stage.
- Building Control inspects the open excavation before concrete goes in. That inspection is not optional.
- Foundation depth is decided by the ground, not by habit - clay soils and nearby trees both push it deeper.
- Nearby trees matter: roots change the moisture in clay and that moves foundations.
- Building over or near a public sewer needs the water authority's agreement, which takes time to obtain.
- Surface water usually cannot go into a foul drain. A soakaway needs a percolation test to size it properly.
The work itself, in plain terms
Excavation & setting out
Setting out from the drawings, excavating to the required depth, and getting the levels and lines right - everything above inherits these.
Strip & trench-fill foundations
Traditional strip footings or trench fill, to the depth and width the ground conditions and loads require, with reinforcement where specified.
Drainage & connections
Foul and surface water runs, inspection chambers, gullies and connections, laid to the correct falls and tested before backfilling.
Soakaways & surface water
Soakaways and attenuation sized from a percolation test rather than guessed, so the garden does not turn into a pond each winter.
Building Control inspections
Excavation and drainage inspections booked at the right moments, so nothing is covered up before it has been signed off.
Concrete, oversite & slabs
Floor slabs, oversite, hardcore, membranes and insulation, ready for the brickwork and the floor build-up above.
Built around how you own the property
Extension projects
The foundation and drainage stage of a domestic extension, done and signed off so the build above can start on solid ground.
Self-builders
Groundworks as a package for a new build or a garden building, coordinated with your engineer's and architect's details.
Commercial & hardstanding
Slabs, bases, drainage and hardstanding for units, yards and parking.
The jobs that start with a phone call
- 01
An extension design drawn without anyone checking what is in the ground or where the drains run.
- 02
A large tree close to the proposed foundation on clay soil, which changes the depth and sometimes the design.
- 03
A drain run discovered directly under the footprint once digging starts.
- 04
Surface water plumbed into a foul drain, which is not permitted and will fail inspection.
- 05
A soakaway that was never percolation-tested and now backs up every winter.
- 06
Concrete poured before the Building Control inspection, which can mean opening it back up to prove it.
What moves the price
Groundworks are quoted from the drawings and a look at the site, because depth and spoil are the two biggest variables and neither can be judged from a plan alone. What moves the price:
Foundation depth
Ground conditions, trees and existing foundations decide it. Deeper means more excavation, more concrete and more spoil.
Spoil removal
Where the arisings go, and whether a lorry can get to them. On a tight terraced plot this is often the biggest single cost.
Access
Whether a digger can reach the dig or it has to be done by hand, which changes the job entirely.
Drainage complexity
Distance to the connection, depth, chambers, and whether a public sewer is involved.
Obstructions
Old foundations, trees, services and drains in the way, found on site rather than on the drawing.
Surface water strategy
A soakaway, a connection or attenuation, and what the percolation test says the ground can take.
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Groundworks & Foundations in Coventry — your questions answered
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Speak to us today0786 5778332How deep do my foundations need to be?
That is decided on site, not in advance: the ground conditions, the loads from above and any nearby trees all set it, and Building Control inspects the open trench and can ask you to go deeper. Anyone quoting a depth before seeing the hole is guessing.
There is a tree near where I want to extend. Does that matter?
On clay, very much. Roots draw moisture out of clay, the clay shrinks and swells, and that moves foundations. It usually means a deeper or differently designed foundation, and occasionally a different position for the extension. Better to establish it at design stage than at excavation.
Can I build over a drain?
Sometimes, with the right protection and the agreement of whoever owns it. If it is a public sewer you will need the water authority's consent, which takes time and has to be started early. A private drain within your boundary is more straightforward but still needs proper treatment, not just building over.
Where does the rainwater go?
Not into the foul drain - that is not permitted. Either into an existing surface water system, if there is one and it has capacity, or into a soakaway sized from a percolation test of your own ground. We do the test rather than assume a standard size.
What happens to all the soil?
It is removed and disposed of, and that is a real cost that belongs in the quote. If you want to keep some for landscaping, say so early and we will stockpile it somewhere it is not in the way of the build.
Who books the Building Control inspections?
We do, for the stages that fall within our work - excavation before concrete, and drainage before backfill. You will get the inspection records, and nothing gets covered up before the inspector has seen it.
Get your groundworks priced in Coventry
Send us the drawings if you have them and we will come and look at the site, the access and where the drains run - the three things that decide what this stage really costs.
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