Basement Conversions · NW11 Golders Green
Hampstead Garden Suburb is a nationally important conservation area governed by the Suburb Trust scheme of management as well as Barnet planning.
This page covers one part of the borough. For the full picture — fees, timelines and the council's current position — read basement conversions in Barnet.
Basement conversions and lowering existing cellars in Golders Green add space without touching the roofline — valuable on NW11's period houses around Golders Green, Hampstead Garden Suburb, Temple Fortune. Barnet Council reviews structural, drainage and flood-risk impact, and a Party Wall award plus a Thames Water build-over agreement are usually required. We coordinate the structural engineer and the waterproofing design.
Full architectural technology service for basement digs and cellar conversions in Golders Green — structural underpinning design, waterproofing strategy, Party Wall coordination, planning where required, and building regulations through to completion certificate.
Across Golders Green, Hampstead Garden Suburb, Temple Fortune in NW11, the dominant property is arts-and-crafts and inter-war detached and semi-detached houses, including the planned hampstead garden suburb, plus golders green terraces. That stock shapes what basement conversion drawings looks like here: the right approach for a period terrace differs from a mansion-block flat or a new-build, and Barnet Council judges each on design quality and neighbour impact. We survey the specific Golders Green property, confirm the planning route — Permitted Development, a Lawful Development Certificate, or full planning — and draw a council-ready set tailored to the NW11 streetscape.
Housing stock in NW11: Arts-and-crafts and inter-war detached and semi-detached houses, including the planned Hampstead Garden Suburb, plus Golders Green terraces.
Within the district: Golders Green, Hampstead Garden Suburb, Temple Fortune.
Streets we know in NW11: the Hampstead Garden Suburb roads, Wildwood Road, Meadway and the Temple Fortune parades. Each road has its own building line, boundary treatment and precedent that Barnet Council weighs when assessing a basement conversion drawings scheme.
Conservation areas: Hampstead Garden Suburb (one of the largest and strictest in the country). Inside these, most external work needs full planning and a Heritage Statement.
Getting around NW11: Golders Green on the Northern line, plus bus links to Hampstead and the suburb.
Property values: around £550,000 for a flat and £1.5m-£3m for a Suburb house — a useful gauge of the build value an extension or loft adds in NW11.
Borough character: Suburban outer-London borough; permitted development used heavily; Hampstead Garden Suburb has its own residents' trust with additional design controls.
Desktop study plus measured survey assessing existing foundations, ground conditions, water table level and underpinning viability for your Golders Green property.
New-build basements and lightwell extensions need planning permission. Cellar conversions of existing space are usually Permitted Development. We confirm the route and submit where needed.
Underpinning sequence drawings, reinforced concrete design, temporary works strategy — all to Eurocode with chartered engineer sign-off.
BS 8102:2022 compliant — cavity drain, cementitious tanking or membrane system specified for Golders Green's ground conditions and water table.
Full Plans application to Barnet Council Building Control or an approved inspector covering structure (Part A), fire safety (Part B), damp-proofing (Part C), ventilation (Part F) and thermal performance (Part L).
Almost every Golders Green basement triggers Party Wall notices. We also manage Thames Water Build Over Agreements where within 3m of a public sewer.
Single planning or building-regs submission.
Planning + building regs + structural.
Listed, conservation or complex sites.
Exceptionally. The Suburb is one of the country's most tightly controlled conservation areas, and changes are governed by the Hampstead Garden Suburb Trust's scheme of management as well as Barnet planning — so you typically need Trust consent and full planning for external work, hedges and even paint colours. We design to the Suburb's detailed standards and handle both consents.
Yes. The inter-war semis and terraces around Golders Green and Temple Fortune, outside the Suburb, suit rear and side extensions and loft conversions, much of it within Permitted Development confirmed by a Lawful Development Certificate. Inside the Suburb, the Trust and conservation controls apply. We confirm which your address falls under.
Almost always. The Hampstead Garden Suburb Trust holds a scheme of management covering the original houses, so most external alterations need Trust approval in addition to Barnet planning permission. We prepare drawings that satisfy both and advise on sequencing the applications.
Family-house extensions and lofts on the inter-war stock — rear kitchen extensions, side infills and hip-to-gable lofts. With houses ranging widely up to £3m in the Suburb, a properly drawn, consent-ready scheme protects both the approval and the value. We handle the planning and Building Regulations drawings together.
With Golders Green property at around £550,000 for a flat and £1.5m-£3m for a Suburb house, the professional drawing fee is a small fraction of the value the work adds to NW11's arts-and-crafts and inter-war detached and semi-detached houses. Barnet Council charges its own statutory application fee on top (currently £548 for a householder planning application, £610 for a full application). We quote the drawings as one fixed price and the free site survey covers every NW11 address.
For a NW11 project across Golders Green, Hampstead Garden Suburb, Temple Fortune, expect roughly 3–4 weeks from instruction to submission: week 1 the measured survey, weeks 2–3 the drawings and your revisions, then validation and the statutory determination by Barnet Council (8 weeks for a householder application). We carry the Golders Green application through every officer query to the decision.
Golders Green (NW11) sits primarily in Barnet, so applications are decided by Barnet Council. Conservation areas within NW11 include Hampstead Garden Suburb (one of the largest and strictest in the country), where full planning and a Heritage Statement are required. We confirm the planning route for your exact address before quoting.
Almost always. Any structural work behind basement conversion drawings in Golders Green — new openings, steel beams, loft floors, foundations — needs Building Regulations approval covering structure (Part A), fire escape (Part B) and insulation (Part L), submitted to Barnet Council Building Control or an approved inspector. On NW11's typically terraced and semi-detached stock, a Party Wall notice to adjoining neighbours is normally required before the steelwork. We coordinate both as part of the Complete package.
In value terms, yes. With Golders Green (NW11) property at around £550, 000 for a flat and £1.5m-£3m for a Suburb house, a well-designed extension or loft typically returns more than it costs in added floor area and sale value. The bigger risk is an unapproved or non-compliant scheme — which is why council-ready drawings and a clean Building Control sign-off matter on NW11 homes.
Neighbouring authorities set their own policies, and the boundary rarely matches the postcode. Full service listings for N2, N3, N10, N12, N20, NW2, NW4 and NW7.
Pick a slot that suits you. No obligation and no sales pressure, just straight answers on your planning route.
Every NW11 postcode district we draw in, the stock that dominates it and the authority that validates a basement conversion there. NW11 fees below are the statutory England rates for 2026, not basement conversion estimates.
| Postcode | Area | Dominant stock | What it means for a basement conversion |
|---|---|---|---|
| NW11 | Golders Green / Hampstead Garden Suburb | Arts & Crafts houses, Edwardian villas | Golders Green / Hampstead Garden Suburb sits wholly inside NW11, so Barnet Council validates every basement conversion submitted from an NW11 address. |
| NW11 | Hampstead Garden Suburb | Arts & Crafts houses, Edwardian villas | Hampstead Garden Suburb sits inside NW11; basement conversion proposals here are determined by Barnet Council. |
| NW11 | Golders Green | Edwardian villas, 1930s semi-detached | Golders Green sits inside NW11; basement conversion proposals here are determined by Barnet Council. |
| N2 | East Finchley | Edwardian terraces, 1930s semi-detached | Adjoining district to NW11, also inside Barnet for basement conversion purposes. |
| N3 | Finchley Central | 1930s semi-detached, Edwardian villas | Adjoining district to NW11, also inside Barnet for basement conversion purposes. |
| N11 | New Southgate / Bounds Green | mixed stock | Adjoining district to NW11, also inside Barnet for basement conversion purposes. |
| N12 | North Finchley / Woodside Park | 1930s semi-detached, Edwardian villas | Adjoining district to NW11, also inside Barnet for basement conversion purposes. |
Roof pitch, wall build-up and plot depth change every few NW11 streets, and each one changes what a basement conversion can achieve at that address.
NW11 (Golders Green / Hampstead Garden Suburb) conservation designations: there are 20 across Barnet Council, Hendon, Golders Green, Monken Hadley among them. Designation costs a NW11 (Golders Green / Hampstead Garden Suburb) owner the permitted-development route: a basement conversion then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Mill Hill is the NW11 (Golders Green / Hampstead Garden Suburb) designation that most often changes a basement conversion design.
NW11 (Golders Green / Hampstead Garden Suburb) permitted development status: there is no borough-wide direction from Barnet Council, so a basement conversion at a NW11 address is normally still permitted development. We certify that with a £274 Lawful Development Certificate rather than leaving a NW11 (Golders Green / Hampstead Garden Suburb) sale to argue it later.
The building fabric around NW11 (Golders Green / Hampstead Garden Suburb): 1930s semi-detached dominates; Edwardian villas in Muswell Hill, Finchley; Garden Suburb Arts & Crafts in Hampstead Garden Suburb; post-war flats in Colindale. Suburban outer-London borough; permitted development used heavily; Hampstead Garden Suburb has its own residents' trust with additional design controls. A basement conversion in NW11 (Golders Green / Hampstead Garden Suburb) is scoped against that stock first, because it decides whether the scheme runs as permitted development, a £274 Lawful Development Certificate, or a full £548 application to Barnet Council.
Sources for this NW11 basement conversion page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
Free fixed quote in 60 seconds. MCIAT chartered.
Get my free quote →Or contact us about your project firstBefore you commit, 30% below London architects and seeing why work with us. You can find your service to find the right fit, or set up your account to track your project. When you are ready, get a quote for your project — most homeowners have a fee in minutes — or contact us and a chartered technologist will be in touch.
