Area guide · WD6
House Extensions in Elstree & Letchmore Heath (WD6)
Extending a house in Elstree or Letchmore Heath? These are two of Hertsmere's historic villages: Elstree village on its hilltop and Letchmore Heath gathered around its green, both wrapped in green belt and both carrying conservation designations at their historic cores. The houses range from timber-framed cottages to substantial detached homes on serious plots, and the projects range with them, from sensitive village-core additions to whole-house programmes on the bigger plots along the lanes. Every one starts the same way: establish the designations on the exact plot, then design something the village would be pleased to keep.
Planning in Elstree & Letchmore Heath
What Hertsmere approves around the two villages
Both villages answer to Hertsmere Borough Council, and its published planning register shows the everyday routes open: single-storey rears and loft conversions clear alongside double-storey and side extensions.
The village dimension changes how you use them. In the conservation cores, approvals go to schemes in honest materials that defer to the historic street; on the green belt lanes, the proportion test against the original building frames how big you can go. Neither is a wall. Both are design briefs, and design briefs are the game we play. The bigger plots between the villages carry the full premium programme, which is why WD6 sits inside our luxury extensions cluster.
The approvals pattern above comes from Hertsmere's published register; it maps the local weather rather than our own workload, and your scheme will stand or fall on its own design.
Local knowledge
The stock, village by village
Elstree village. Along Barnet Lane and the High Street ridge, period cottages and villas mix with substantial later houses. Core plots take carefully detailed rear additions; the larger houses off the ridge carry double-storey reworks (£95,000 to £205,000) where the massing is handled with respect.
Letchmore Heath. The houses around the green are the picture-postcard end of Hertsmere, many protected, all scrutinised. Work here is quiet and crafted: walled-garden additions, matched brick and clay tile, joinery done the traditional way. It rewards patience and punishes shortcuts, which suits how we design and run a project.
The lanes between. Along Allum Lane and the roads toward Aldenham, detached houses sit on deep green belt plots. This is the premium territory: wide glazed rears (£55,000 to £115,000), wrap-arounds (£90,000 to £175,000) and extension-plus-remodel programmes designed around the original-building test in our green belt guide.
The newer detached stock. WD6 has a generation of substantial modern houses where the volume already exists and the brief is reconfiguration: kitchen wings, first-floor reworks, the occasional basement.
Every street is different. That's the point.
We design to Elstree & Letchmore Heath's stock and to what the council demonstrably approves — not to a template. A free site visit tells you what your house can take.
Get my free estimateHonest numbers
What an extension costs in Elstree and Letchmore Heath in 2026
Village work carries a specification premium, conservation detailing especially. All-in build ranges, excluding VAT, professional fees and kitchen fit-out:
| Extension type | Typical WD6 cost | On-site time | Usual planning route |
|---|---|---|---|
| Side-return extension | £45,000 to £85,000 | 2 to 3 months | Often permitted development |
| Single-storey rear | £55,000 to £115,000 | 3 to 4 months | PD outside the conservation cores |
| Kitchen extension (incl. mid-range kitchen) | £70,000 to £135,000 | 3 to 4 months | As above |
| Hip-to-gable loft + rear dormer | £65,000 to £110,000 | 6 to 10 weeks | Usually PD outside the cores |
| Wrap-around extension | £90,000 to £175,000 | 4 to 6 months | Full application |
| Double-storey rear | £95,000 to £205,000 | 5 to 7 months | Full application |
Work to £3,200 to £5,200 per square metre depending on setting and specification, with the larger programmes banded in the luxury extension cost guide. Fixed, itemised quote after a free visit; the signed number is the paid number.
Permissions, handled
Planning here: three layers to read
Conservation areas at the cores. Inside them, permitted development narrows sharply: the larger-home 8m route does not apply, side extensions lose PD rights and design expectations rise. Outside the cores, the normal allowances usually hold.
Green belt between the settlements. Plots on the lanes are measured against the original building. We establish that baseline, and the headroom previous extensions have used, before designing anything.
The parish voice. Letchmore Heath sits within Aldenham parish, whose council comments on applications. Well-prepared schemes give the consultation nothing to object to.
A householder decision takes roughly eight weeks at Hertsmere, and for anything built under PD we secure a Lawful Development Certificate so the position is documented when you sell.
How it works
How it works
- Free design visit. Designations mapped, plot walked, honest advice on scope, budget and route.
- Design and drawings. Composed to the village's language and the policy tests it must pass.
- Planning, handled. Application and consultations managed through Hertsmere to the decision notice.
- Fixed-price build. Craftsmanship to match the setting, building control signed off, handover immaculate.
Questions, answered
Elstree & Letchmore Heath extension FAQs
Can I extend inside the conservation areas?
Yes, with design that earns it: honest materials, additions subordinate to the host building and detailing done traditionally. PD rights narrow inside the cores, so most schemes go to full application, which we manage end to end.
How does the green belt affect the lanes?
Extensions on green belt plots must not be disproportionate to the original building, meaning the house as first built. Previous additions count against the allowance, so we calculate your remaining headroom before design begins.
What will my extension cost in WD6?
Budget £3,200 to £5,200 per square metre in 2026. Glazed single-storey rears typically run £55,000 to £115,000 and double-storey schemes £95,000 to £205,000, excluding VAT and fees, with the larger programmes banded in our luxury cost guide. Quotes are fixed and itemised.
Which council do applications go to?
Hertsmere Borough Council for both villages, with Aldenham Parish Council consulted on the Letchmore Heath side. Standard householder decisions take around eight weeks.
Do you work on listed buildings?
Yes. Where a cottage or villa is listed, listed building consent runs alongside the planning application and we prepare both together, with the heritage case written into the drawings.
How long from first visit to finished build?
A few weeks of design, roughly eight in planning, then three to seven months on site depending on scale. You get honest programme dates with the quote and we hold to them.
What we build in Elstree & Letchmore Heath
The same team designs, gets planning and builds — one fixed, itemised price whichever route your Elstree & Letchmore Heath project takes.
- Kitchen extensions in Elstree & Letchmore Heath
- Side return extensions in Elstree & Letchmore Heath
- Double-storey & wrap-around in Elstree & Letchmore Heath
- Loft conversions in Elstree & Letchmore Heath
- Garden rooms & offices in Elstree & Letchmore Heath
- Annexes in Elstree & Letchmore Heath
Checking the rules for Elstree & Letchmore Heath first?
What clients say
Rated 5.0 on Google
“The Extension Company built a 5m single storey rear extension on our Victorian terrace in Crouch End. Went down the permitted development route so no planning application needed, which they explained up front and saved us months. Kitchen-diner now opens onto the garden with sliding doors. £87k all in, matched the quote.”
“From the initial site visit onwards to my property in Barnet, we felt that the team actually listened to what we wanted. They suggested a few changes to the layout that we hadn't considered, and those changes have made a huge difference. Would definitely use again and recommend”
“Used The Extension Company for a loft conversion on our semi detached in Barnet and couldn't be happier. They explained what was possible at the first visit, sorted the planning side, and gave a fixed price with no surprises at the end. The hip-to-gable and rear dormer gave us a big double bedroom with an en-suite. Tidy, professional and finished on schedule. Would recommend to anyone in North London thinking about a loft conversion.”
“We had been putting off our loft conversion for years because the whole process felt overwhelming. The team made it much easier than expected and handled the drawings, planning and build for us. We now have a lovely extra bedroom and shower room.”
“Our wrap-around extension has completely transformed the ground floor. We now have the open plan kitchen and family space we wanted without losing all of the garden. Thanks to everyone involved.”
“Really pleased with the work from The Extension Company. We had our extension done in Hampstead and the whole experience was excellent. Great communication from start to finish, The quality of the finish is excellent and we’re really happy with the result. Would definitely recommend them if you’re thinking about an extension.”
Reviews shown word for word from our Google profile. See 9 more client reviews · Read all 16 reviews on Google
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