Can I build a glazed orangery in a Richmond conservation area?

Yes, but Richmond Council's SPD places specific design requirements on glazed extensions in conservation areas. All-glass frameless structures are generally not accepted. The preferred form is brick piers with glazed infill, or a traditional orangery with solid masonry elements. Planning permission is required. Appoint an architect with Richmond conservation area experience to advise on the design before committing to a contractor.

House Extension Richmond: Vetted Builders, Matched Quotes

Q: How much does a house extension cost in Richmond?

Typical all-in costs in Richmond: single-storey rear extension £65,000–£110,000; side return extension £35,000–£62,000; wraparound (rear + side return) £85,000–£150,000; double-storey extension £110,000–£200,000+. Richmond, Kew, Barnes, and East Sheen (TW9, TW10, SW13, SW14) sit at inner London rates — 20–30% above the London average. Twickenham, Teddington, and Hampton run closer to the London average. Conservation area extensions require planning — add £4,000–£8,000 for architect and professional fees.

Q: How long does a house extension take in Richmond?

Planning takes 8–12 weeks (Richmond Council is slower than average). The build takes 8–24 weeks depending on extension type. Total from decision to completion: 8–12 months for a single-storey in a conservation area, 10–14 months for a double-storey. Allow additional time for party wall agreements (2–3 months) and design and tender (2–3 months).

Q: What extension type suits my Richmond Victorian or Edwardian terrace?

The most popular option for Richmond terraces is a wraparound extension combining the side return with a full-width rear extension to create a large open-plan kitchen-diner. For Edwardian semis in Ham, Kew, and St Margarets, a double-storey rear extension adds both a ground-floor kitchen-diner and an additional bedroom. If budget is tighter, a side return alone adds useful kitchen floor area on a narrow Victorian or Edwardian terrace.

Q: What materials does Richmond Council require for a conservation area extension?

Extensions in Richmond conservation areas must use materials that match or complement the existing property. For Victorian and Edwardian brick terraces, this typically means London stock brick to match. uPVC windows are not acceptable — conservation-grade timber windows are required. Flat roofs with concealed parapets are generally preferred. All-glass frameless extensions are not generally accepted — brick piers with glazed infill are the preferred form for orangeries and garden rooms.

Q: Do I need a party wall agreement for a house extension in Richmond?

Almost certainly yes for a terrace or semi-detached property. Most Richmond extension projects involve structural work within 3–6 metres of a neighbouring foundation or on a shared wall, triggering the Party Wall etc. Act 1996. Serve notice early — allow 2–3 months for the process.

A house extension in Richmond upon Thames costs £65,000-£120,000 for a single-storey rear extension and £110,000-£200,000+ for a double-storey. Richmond has 76 conservation areas and strict design guidance; most extensions require full planning permission. Get 3 matched quotes from vetted Richmond extension specialists.

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How much does a house extension cost in Richmond?

House extension costs in Richmond upon Thames vary by extension type, size, and location within the borough. Richmond (TW9, TW10), Kew, Barnes (SW13), and East Sheen (SW14) sit at inner London rates, typically 20-30% above the London average. Twickenham (TW1, TW2), Teddington (TW11), and Hampton (TW12) run closer to the London average.

Richmond conservation areas: In all 76 of Richmond's conservation areas, Permitted Development rights for extensions are removed. All rear extensions, side returns, wraparounds, and double-storey extensions require full planning permission.

Extension type	Typical cost range	Planning status	Notes
Single-storey rear extension
Single-storey rear extension — outside conservation area (up to 3m depth, terrace/semi)	£65,000–£95,000	Permitted Development Building regs	Up to 3m rear extension for terraces/semis may be PD outside CAs. Prior Approval scheme allows up to 6m via neighbour consultation. Building regs required.
Single-storey rear extension — inside conservation area	£72,000–£110,000	Planning required Building regs	All rear extensions in Richmond CAs need full planning. Materials must match existing property. Add £4,000–£7,000 for architect and planning fees. Allow 10–12 weeks for determination.
Single-storey rear extension — large (5–6m depth, open-plan kitchen-diner)	£85,000–£130,000	Planning required Building regs	Extensions over 3m (terraces/semis) or 4m (detached) require planning outside CAs too. Lantern roof, bi-fold doors, or full-width glazing at higher end of cost range.
Side return extension
Side return extension — outside conservation area	£35,000–£55,000	Check PD limits Building regs	Side extensions that project beyond the principal elevation require planning in most cases. Check specific PD rules with a planning consultant before assuming no planning is needed.
Side return extension — inside conservation area	£38,000–£62,000	Planning required Building regs	Planning required in all Richmond CAs. Side return height must not exceed ground-floor eaves. Roof should be flat with concealed parapet — Richmond SPD guidance applies.
Wraparound extension (rear + side return)
Wraparound extension — outside conservation area	£85,000–£130,000	Planning required Building regs	Wraparound extensions almost always require planning regardless of CA status — the side component typically triggers planning even outside CAs.
Wraparound extension — inside conservation area	£92,000–£150,000	Planning required Building regs	Most popular high-specification extension type for Richmond terraces. Planning required. Materials and design scrutinised closely in conservation areas. Allow 10–14 months total including planning.
Double-storey extension
Double-storey rear extension — outside conservation area	£110,000–£160,000	Planning required Building regs	Double-storey extensions are not Permitted Development — full planning required everywhere. Adds a ground-floor room and a first-floor bedroom or bathroom. Better cost per m² than two separate projects.
Double-storey rear extension — inside conservation area	£120,000–£200,000+	Planning required Building regs	Planning required. Overlooking and privacy assessments apply — Richmond Council scrutinises double-storey rear extensions on all elevations. Most common on larger semis in Ham, Kew, and St Margarets.
Specialist extension types
Glazed orangery or garden room	£55,000–£110,000	Planning required (in CA) Building regs	Richmond SPD: all-glass frameless extensions not generally accepted in CAs. Brick piers with glazed infill preferred. Outside CAs, may be PD if within size limits. Building regs for glazing energy standards.
Basement extension	£3,500–£6,000/m²	Planning required Building regs	Significant structural and waterproofing works. Requires planning and structural engineer from the outset. Party wall Act almost always triggered. Programme: 24–40 weeks on site. Most common in Richmond Hill, Ham, and Kew.
Professional fees
Architect (planning drawings and Building Regs)	£3,000–£8,000	Required for planning	Essential in conservation areas. Choose an architect with Richmond Council conservation area experience. Fee covers planning drawings, application submission, and Building Regulations drawings.
Structural engineer	£1,000–£2,500	Building regs	Required for all structural elements — steelwork calculations, foundation design, and any structural wall removal. Building Control requires signed-off structural calculations.
Richmond Council planning fee (householder)	£258	Required for planning	Fixed householder application fee. Does not include architect or pre-application advice fees.
Party wall surveyor	£700–£1,500 per owner	Required where applicable	Most Richmond terrace and semi-detached extensions trigger the Party Wall etc. Act 1996. Allow 2–3 months. Costs rise if neighbour appoints own surveyor.
Kitchen fit-out (where extension creates kitchen-diner)	£8,000–£25,000+	No planning Building regs	Separate cost to the extension structure. Mid-range kitchen £10,000–£18,000; high specification £20,000–£40,000+. Building regs for gas and electrical works.

Single-storey rear extension

Rear extension — outside CA (up to 3m) £65,000–£95,000

Permitted Development Building regs

May be PD outside CAs. Prior Approval allows up to 6m via neighbour consultation.

Rear extension — inside CA £72,000–£110,000

Planning required Building regs

All rear extensions in Richmond CAs need full planning. Materials must match.

Large rear extension (5–6m, open-plan) £85,000–£130,000

Planning required Building regs

Always needs planning over 3m (terraces). Lantern roof/bi-folds at upper end.

Side return extension

Side return — outside CA £35,000–£55,000

Check PD limits Building regs

Check specific PD rules — side extensions often trigger planning even outside CAs.

Side return — inside CA £38,000–£62,000

Planning required Building regs

Planning required. Height not to exceed ground-floor eaves. Flat roof with parapet preferred.

Wraparound extension

Wraparound — outside CA £85,000–£130,000

Planning required Building regs

Almost always needs planning — side component typically triggers it even outside CAs.

Wraparound — inside CA £92,000–£150,000

Planning required Building regs

Most popular high-spec option for Richmond terraces. Allow 10–14 months total.

Double-storey extension

Double-storey — outside CA £110,000–£160,000

Planning required Building regs

Not Permitted Development anywhere. Adds ground-floor room + first-floor bedroom.

Double-storey — inside CA £120,000–£200,000+

Planning required Building regs

Planning required. Overlooking assessments apply. Common on larger semis in Ham, Kew, St Margarets.

Specialist and fees

Glazed orangery / garden room £55,000–£110,000

Planning required (in CA) Building regs

Richmond SPD: frameless glass not accepted in CAs. Brick piers with glazed infill preferred.

Basement extension £3,500–£6,000/m²

Planning required Building regs

Structural and waterproofing works. 24–40 weeks on site. Common in Richmond Hill, Ham, Kew.

Architect (planning + Building Regs) £3,000–£8,000

Required for planning

Choose an architect with Richmond Council conservation area experience.

Structural engineer £1,000–£2,500

Building regs

Required for all structural elements. Building Control requires signed calculations.

Planning fee (householder) £258

Required for planning

Fixed fee. Does not include architect or pre-application advice fees.

Party wall surveyor £700–£1,500 per owner

Required where applicable

Most Richmond terrace extensions trigger the Party Wall Act. Allow 2–3 months.

Kitchen fit-out £8,000–£25,000+

No planning Building regs

Separate to the extension structure. Mid-range £10,000–£18,000; high spec £20,000–£40,000+.

Cost ranges are all-in indicative figures for Richmond upon Thames including VAT, structural engineer, and project management. They exclude planning fees, architect fees, and kitchen fit-out unless stated. Richmond (TW9, TW10), Kew, Barnes (SW13), and East Sheen (SW14) sit at inner London rates — typically 20–30% above the London average. Twickenham (TW1, TW2), Teddington (TW11), and Hampton (TW12) run closer to the London average.

What drives cost variation for Richmond house extensions:

– Extension type – a single-storey rear extension is the most common starting point. A side return fills the gap beside a Victorian or Edwardian terrace. A wraparound combines both. A double-storey adds a first-floor room above.

– Size – most Richmond single-storey extensions run 20-40m². Cost per m² reduces slightly at larger sizes.

– Conservation area – conservation area extensions require planning permission (adding £3,000-£8,000 in professional fees and 3-5 months to the programme) and often specified materials (brick to match, conservation-grade windows). Budget 10-15% above non-CA rates for materials compliance.

– Structural complexity – removing a rear wall to open up the ground floor adds steelwork costs (£2,000-£6,000). Most single-storey extensions involve at least one RSJ.

– Specification – a glazed kitchen-diner extension with lantern roof and bi-fold doors sits at the higher end. A brick-built utility or garden room sits lower.

– Services – extending a kitchen requires drainage diversion, replumbing, and electrical works. Allow £4,000-£8,000 for services over and above the structure.

Do I need planning permission for a house extension in Richmond?

Richmond upon Thames has 76 conservation areas, and most extension work in the borough requires full planning permission. Richmond Council is stricter than average; its approval rate for householder applications is 81% compared to 90% nationally.

In conservation areas: Permitted Development rights for extensions are removed. All rear extensions, side return extensions, wraparound extensions, and double-storey extensions in Richmond conservation areas require a full planning application.

Outside conservation areas: Standard Permitted Development rules apply: a single-storey rear extension of up to 3m depth (for terraces and semis) or 4m (for detached properties) may be built under PD. The Prior Approval (Neighbour Consultation) scheme allows up to 6m for terraces/semis and 8m for detached under a simplified process. Extensions beyond these limits always require full planning.

Richmond Council’s Supplementary Planning Document (SPD): even where PD rights exist, Richmond Council’s SPD sets design standards that many homeowners choose to follow voluntarily. Key SPD guidance:

– Extension materials must match or complement the existing property; no uPVC windows; no render on brick properties in most areas

– Flat roofs with concealed parapets are preferred in conservation areas over pitched roofs that interrupt the roofline

– Side return extensions should not be higher than the ground floor eaves

– Glazed extensions (orangeries, lantern roofs) are subject to specific design guidance in conservation areas; frameless glass is generally not acceptable

Listed buildings: any extension to a listed building (common in Richmond Hill, Ham, and Petersham) requires Listed Building Consent in addition to planning permission. Works affecting the character of a listed building are very tightly controlled.

Richmond Conservation Areas - House extension planning rules

In Richmond's conservation areas, Permitted Development rights for extensions are removed. All extension types single-storey rear, double-storey, side return, wraparound, and orangery require a full planning application. There are no PD exceptions.

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Conservation Area	Area / Postcodes	Single-storey rear	Double-storey	Side return	Notes
Richmond Hill	Richmond TW10	Planning req.	Planning req.	Planning req.	Many listed buildings — LBC may also be required
Richmond Green	Richmond TW9	Planning req.	Planning req.	Planning req.	—
Richmond Town Centre	Richmond TW9	Planning req.	Planning req.	Planning req.	—
St Margarets	St Margarets TW1	Planning req.	Planning req.	Planning req.	—
Twickenham Riverside	Twickenham TW1	Planning req.	Planning req.	Planning req.	—
Marble Hill	Twickenham / St Margarets TW1	Planning req.	Planning req.	Planning req.	Registered park setting — stricter assessment
Kew Green	Kew TW9	Planning req.	Planning req.	Planning req.	Adjacent to Kew Gardens WHS buffer zone
Kew Road	Kew TW9	Planning req.	Planning req.	Planning req.	—
Barnes Village	Barnes SW13	Planning req.	Planning req.	Planning req.	—
Castelnau	Barnes SW13	Planning req.	Planning req.	Planning req.	—
East Sheen	East Sheen SW14	Planning req.	Planning req.	Planning req.	—
Mortlake High Street	Mortlake SW14	Planning req.	Planning req.	Planning req.	—
Ham House & Gardens	Ham TW10	Planning req.	Planning req.	Planning req.	Historic England registered park — pre-app advice recommended
Petersham	Petersham TW10	Planning req.	Planning req.	Planning req.	Historic village — conservation officer pre-app recommended
Strawberry Hill	Strawberry Hill TW1	Planning req.	Planning req.	Planning req.	—

Richmond Hill

Richmond TW10