Everything above depends on this · All 32 London boroughs
Foundations in London
Trench fill, strip, raft and underpinning, with engineer's calculations and inspection.
Screed, in progress
Sand and cement screed laid over insulation before the final floor finishWhat we do
Foundation depth in London is driven by clay subsoil, tree proximity and neighbouring structures — and it is the one element building control will always inspect before it is covered. We dig to the engineer's design, not to the minimum.
Included as standard
- Trench fill and strip foundations
- Raft foundations for poor ground
- Underpinning and structural stabilisation
- Clay heave protection and compressible fill
- Engineer's calculations and building control inspection
- Below-ground drainage and service ducting
- Typical timescale
- 1–3 weeks
- Coverage
- 32 boroughs
- Payment
- In arrears
- Trading since
- 2008
Depth, ground conditions and inspection
Foundation depth in London is driven by the ground rather than by a standard detail. Much of the capital sits on London Clay, which shrinks and swells with moisture content, so foundations have to reach below the zone of seasonal movement.
Trees make that harder. A mature tree close to the works draws moisture from the clay and can require substantially deeper foundations, sometimes with compressible material against the trench face to accommodate heave. Species and distance both matter, and the design comes from a structural engineer rather than from habit.
Foundations are the inspection stage that cannot be missed. Building control inspects the open trench before concrete is poured, and again afterwards. An inspector arriving after the pour can require the work to be opened up, which is the most expensive possible way to learn the process.
Where an existing structure has moved, underpinning transfers its load to a deeper stratum, in sequenced bays so the building is never undermined along its full length at once. It is engineered work, not a bigger version of digging a trench.
The limits above are the national permitted-development rules for England. Your borough may restrict them further through a conservation area or an Article 4 direction — we confirm the position for your address in writing before quoting.
Our work
Foundations we have completed
Answers
Foundations — common questions
Do I need planning permission for foundations in London?
It depends on the property type and what is proposed. Many single-storey rear extensions and loft conversions fall under permitted development, but those rights do not apply to flats and are restricted in conservation areas or where an Article 4 direction applies. We check the planning position for your specific address before quoting, and tell you in writing which route applies.
How do you price the work?
From a site survey, written up as a fixed and itemised scope before any deposit is discussed. If something genuinely unforeseen appears once work is opened up, it is priced and agreed in writing before we continue — never added to the final invoice after the fact.
When do I pay?
In arrears of work completed. You pay for work that has been done and inspected, not for work that has been promised. This has been how the company operates since 2008.
Do you handle Party Wall notices?
Yes, where the work requires them. Under the Party Wall etc. Act 1996, notifiable work on a shared wall needs 2 months written notice to the adjoining owner, while excavation near a neighbouring structure and building at the line of junction need 1 month. We serve the notices and manage the award process as part of the job.
Will I get certificates at the end?
Yes. Electrical work is tested and certificated under Part P, and building control issues a completion certificate where an application was required. You receive the handover pack — it is what a buyer's solicitor will ask for when you eventually sell.
How long will it take?
It depends entirely on scope, and we give a programme with the written quote rather than a guess on the phone. What we will not do is start a job we cannot resource, which is the usual reason a build stalls halfway through.
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