Basement
conversions
in Richmond, TW9
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We design and build Richmond basement conversions with basement excavation, cellar conversion, and underpinning for properties on Richmond Hill, The Vineyard, Maids of Honour Row - structural engineering, party wall coordination, underpinning, waterproofing, drainage pumps, lightwells and full interior fit-out for period homes, townhouses and prime London properties where ground conditions, neighbour risk and sequencing need handling properly.
Basement Conversions in Richmond: What You Need to Know
Every basement conversion project in Richmond is designed to respect the Richmond Hill Conservation Area and the character of Georgian riverside houses, Victorian terraces, park-facing mansion flats. Our in-house RIBA Chartered Architects handle Richmond upon Thames planning applications, our chartered structural engineers specify any load-bearing work, and our directly-employed trades deliver the build under one fixed-price contract. We coordinate Building Control, Party Wall awards where needed, and all certifications through to handover.
Richmond falls within a conservation area, which means visible external alterations require careful design and often full planning permission. Our architects have extensive experience securing approvals in Richmond's conservation areas.
Our basement conversion projects in Richmond are delivered by our in-house team of RIBA architects, structural engineers and specialist tradespeople. Every project is managed under a single fixed-price contract with no hidden costs.
Richmond is one of London's great historic towns, and a basement here is heritage work of a high order. Richmond upon Thames scrutinises external change exceptionally closely, listed-building consent applies widely, and its Georgian riverside houses, Victorian terraces and period homes mean visible changes to elevations, roofs, windows and boundaries all need early consent checks. The Georgian houses on Richmond Hill and the early-Georgian terraces of Richmond Green and Maids of Honour Row are restored with authentic brick, joinery and plaster within a strictly protected setting, many of them listed.
The townscape carries a statutory protection few areas match. The celebrated view from Richmond Hill is safeguarded by the Richmond, Ham and Petersham Open Spaces Act 1902, and four conservation areas — Richmond Green (No. 3), Richmond Riverside (No. 4), Richmond Hill (No. 5) and Central Richmond (No. 17) — each carry a published statement. Even subterranean work sits within that guarded setting, so lightwells, railings and garden-level structure are designed to respect the protected outlook, and the consent strategy leads the scheme throughout.
On cost, converting existing space runs £750–£3,000 per square metre (over £6,000 finished); a new dig with underpinning is £2,100–£4,000 per square metre before fit-out.
Basement Conversions in Richmond: Applied to the Local Stock
Richmond sits in the London Borough of Richmond upon Thames, with conservation areas including Richmond Hill and the Green protecting one of the finest townscapes in London — with a high concentration of listed Georgian houses and protected river views. Richmond town and its riverside are covered by four conservation areas, each with a published conservation area statement: Richmond Green (No. 3), Richmond Riverside (No. 4), Richmond Hill (No. 5) and Central Richmond (No. 17). The Richmond Hill Conservation Area was designated on 14 January 1969 and extended in 1975, 1977 and 2000; the celebrated view from Richmond Hill is protected by the Richmond, Ham and Petersham Open Spaces Act 1902.
Sources: Richmond upon Thames Council - Conservation area statements (+ Richmond Hill CA appraisal) (2026); Richmond upon Thames Council - Conservation area statements (2026); Richmond upon Thames Council - Richmond Hill Conservation Area Appraisal (2026)
What a Basement Conversion Involves
Digging out a basement adds a complete new storey without touching the garden or the street elevation — and it is the most engineering-led work we do. Ground conditions, foundation depths and the water table are investigated before a price is ever fixed, because below-ground surprises are expensive precisely when they are unplanned. Each project moves through four disciplines, delivered by one team under one contract.
- Excavation — the dig itself, planned around access, spoil removal logistics and temporary support of the house above
- Underpinning — foundations deepened in short, engineer-sequenced sections, with movement monitoring on your property and your neighbours’ throughout
- Waterproofing — a tanked, integral or cavity-drain system (Type A, B or C to BS 8102) selected for your site’s ground conditions, not by habit
- Fit-out — insulation, ventilation, light wells, staircase, plaster and finishes brought to the same standard as the floors above
How We Run Your Project
Below-ground work punishes improvisation, so every stage is closed out before the next one starts.
- Ground investigation — bore holes establish soil type, bearing capacity and water table before feasibility is confirmed.
- Design & consents — layout, light wells and stair position from our architects; underpinning sequence from our structural engineers; planning and any Basement Impact Assessment handled for you.
- Fixed-price contract — priced after the soil investigation, so ground conditions are our risk rather than your variation.
- Excavation & underpinning — sequenced digs and pours with live structural monitoring, never more than the engineer’s design allows at once.
- Waterproofing & shell — membrane or structural system installed and inspected before anything conceals it, with sump and pump provision where the site needs it.
- Fit-out & handover — services, finishes, building control sign-off and a certification pack at completion.
On site, expect 12–16 weeks for a cellar conversion and 16–24 weeks for a full dig-down — the curing time between underpinning sections cannot safely be compressed. Read the full basement conversion guide for waterproofing systems, ceiling heights and light-well design in depth.
The regulatory load is real: a chartered structural engineer must design and certify the underpinning methodology, and most excavations within three metres of a neighbouring building engage the Party Wall etc. Act 1996 — notices, schedules of condition and often a formal award before work can start. Many boroughs add a Basement Impact Assessment covering hydrology and construction management. Our planning guide library sets out what applies where.
Why Hampstead Renovations
Basements fail when design, engineering and waterproofing are handled by separate firms working from different assumptions. Here they sit under one roof: in-house RIBA Chartered Architects shape the space, our own structural engineers design and supervise the underpinning, and RICS surveying support through our sister company covers party wall and condition matters. Every project carries £10M public liability cover, a genuinely fixed price agreed after ground investigation, and a 10-year structural and waterproofing warranty. Send an enquiry before 2pm on a weekday and you will hear back from us that same day.
Basement Conversions in Richmond: Questions
Is a basement in Richmond mostly a heritage project?
Very often, yes. Richmond upon Thames scrutinises external change exceptionally closely, listed-building consent applies widely, and protected views and flood risk add their own constraints. Its Georgian riverside houses, Victorian terraces and period homes mean refurbishment here is frequently heritage work, so a basement is designed around a listed or conservation-area shell, with visible changes to elevations, roofs, windows and boundaries needing early consent checks.
Does the protected Richmond Hill view affect below-ground work?
It governs the setting. The celebrated view from Richmond Hill is protected by the Richmond, Ham and Petersham Open Spaces Act 1902, and the Richmond Hill Conservation Area was designated in 1969 and later extended. A basement is subterranean, but its lightwells, railings and any garden-level structure still sit within one of the most carefully guarded townscapes in London, so the scheme is drawn to respect that protected outlook.
Which Richmond conservation areas apply?
Four cover the town and its riverside. Richmond town and riverside fall under Richmond Green (No. 3), Richmond Riverside (No. 4), Richmond Hill (No. 5) and Central Richmond (No. 17), each with a published conservation-area statement. Richmond Hill carries grand Georgian houses by the protected river view, and Richmond Green and Maids of Honour Row bring exquisite early-Georgian terraces, so the relevant designation shapes how a basement is judged.
What does a basement conversion cost in Richmond?
The structural route decides it. Converting existing below-ground space is guided at £750–£3,000 per square metre of converted area, and above £6,000 per square metre once fully finished. A new excavation with underpinning is the larger figure — £2,100–£4,000 per square metre of dug area, before the fit-out. On listed Georgian houses, the conservation-led restoration of brick, joinery and plaster above the works sits in the budget beside the dig.
Can a listed Georgian house on Richmond Hill take a basement?
With consent at each step. The Georgian houses on Richmond Hill and the early-Georgian terraces of Richmond Green and Maids of Honour Row need conservation-led restoration of brick, joinery and plaster within a strictly protected setting; many are listed, so interiors are reconfigured and re-serviced with consent secured at each stage. A basement beneath such a house is possible but is led entirely by the consent strategy, which keeps the scheme on track.
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