Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Call 020 8037 7332 or get an instant estimate online.
Permitted development · No planning application · London & Hertfordshire
Permitted development lofts and extensions: fixed price, no planning application — from £42,000 inc. VAT (£35,000 + VAT)
By Anderson & the LCCL Construction Team
Finchley N3 · Design & build, LABC award winners 2024 and 2026
Most London terraces and semis can take a rear dormer loft, a hip-to-gable, a 3-metre rear extension or a side-return infill without a planning application. These are the projects we build most, at economy specification and a fixed price for the scope on the drawings, with the Lawful Development Certificate applied for and included. If the house qualifies, the planning risk is gone before you pay a deposit — and on site it is six to twelve weeks.
Quick answer
From £42,000 inc. VAT (£35,000 + VAT) for a 3 m rear extension or side return; from £56,400 inc. VAT (£47,000 + VAT) for a rear dormer loft. Economy specification, postcode dependent.
None. Each project below sits inside the permitted development rules; we apply for the Lawful Development Certificate and include it in the price.
4–12 weeks on site depending on the project; 8–12 weeks of design, certificate and building regulations before that.
A free 30-minute phone call with our team, no obligation.
From
£42,000 inc. VAT (£35,000 + VAT)
Planning
None — Lawful Development Certificate included
On site
4–12 weeks
Guarantee
12-month workmanship guarantee; 10-year LABC structural warranty
LABC Building Excellence Award 2024
Best Residential Extension in London — Bohun Grove, East Barnet EN4: rear extension, hip-to-gable loft conversion and whole-house renovation
LABC Building Excellence Awards 2026
London Regional Winner, Best Conversion or Alteration — Weech Road, Hampstead NW6: penthouse loft conversion and full renovation
One contract
Architecture, structural engineering, planning, construction and project management — all under one contract
Guaranteed & insured
12-month workmanship guarantee; 10-year LABC structural warranty
What a permitted development project from LCCL includes
Design and build inclusive at economy specification — the price covers the whole job, from the survey to the completion certificate.
Measured survey and a permitted development check of your house (allowance used, conservation area, Article 4)
Architectural design and drawings, with revisions until you're happy
Lawful Development Certificate application, prepared and submitted for you
Structural engineer's calculations
Building-regulations drawings and full-plans submission through LABC
Party wall notices served to your neighbours
The build: structure, roof, windows and doors, insulation, plumbing and electrics, plastering
Economy specification finish — upgrade levels agreed on the call
LABC inspections and the completion certificate
12-month workmanship guarantee and a 10-year LABC structural warranty
Permitted development projects and prices in 2026
Economy specification, inc. VAT with the ex-VAT figure in brackets. Every project is priced from your postcode and house type.
Project
What it gives you
From
Velux / rooflight loft
Light, a small room or storage; uses almost none of the PD allowance
£32,400 inc. VAT (£27,000 + VAT)
Rear dormer loft (terrace or semi)
Double bedroom and shower room in 6–8 weeks
£56,400 inc. VAT (£47,000 + VAT)
L-shaped dormer loft (terrace with outrigger)
Two rooms and a bathroom from the 40 m³ allowance
£58,800 inc. VAT (£49,000 + VAT)
Hip-to-gable + rear dormer (semi)
The full semi-detached loft: bedroom, bathroom, proper stair
£60,000 inc. VAT (£50,000 + VAT)
3 m rear extension (4 m detached)
Open-plan kitchen-diner, 15–20 m²
£42,000 inc. VAT (£35,000 + VAT)
Side-return infill (terrace)
A full-width kitchen under a glazed roof
£42,000 inc. VAT (£35,000 + VAT)
Single-storey side extension (semi)
Utility, wider kitchen or shower room where the garage or path was
£42,000 inc. VAT (£35,000 + VAT)
Garage conversion
A room from the garage, internal works only
Priced individually
Planning-route step-ups
When you need them
Guide range
Mansard loft
When a dormer or hip-to-gable will not give the space — almost always a planning application
£76,800 – £148,800 inc. VAT (£64,000 – £124,000 + VAT)
10–14 wks
Wraparound extension
Rear and side in one scheme — falls outside permitted development
£72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT)
10–14 wks
6–8 m rear extension
Prior approval route: 42-day neighbour consultation instead of a full application
£60,000 – £90,000 inc. VAT (£50,000 – £75,000 + VAT)
10–12 wks
What the price includes: survey and PD check, drawings, the Lawful Development Certificate, structural calculations, building-regulations submission, party wall notices, the structure, roof, glazing openings, insulation, first and second fix to economy specification, inspections and the completion certificate.
What moves the price: the postcode; the size (price moves from 9 m² upward); a bathroom or shower room in a loft; the steel to open the existing back wall into an extension; kitchen units, bathroom fittings and floor coverings, which are priced as separate lines; and the finish level, which is agreed on the call.
Does your house qualify? The checks that decide it
It is a house, not a flat
Permitted development rights belong to houses. Flats and maisonettes have none, so every loft or extension on a flat needs a planning application.
Not in a conservation area or on an Article 4 street
Conservation areas restrict side and rear extensions and dormers in most boroughs; an Article 4 direction removes permitted development rights on specific streets. We check both before drawing.
The allowance has not been used up
A loft allowance of 40 m³ (terrace) or 50 m³ (semi or detached) and an extension allowance measured from the original house. A dormer or extension added by a previous owner counts against it.
The design stays inside the limits
Lofts: below the ridge, 20 cm back from the eaves, no front dormer, no balcony. Extensions: 3 m (4 m detached) deep, 4 m high, 3 m eaves within 2 m of a boundary, no more than half the garden, side extensions no wider than half the house.
One scheme, not a combination that becomes a wraparound
A rear and a side extension built together count as one extension and need planning. A loft plus a rear extension is fine — different classes, both allowances available.
Planning
Do permitted development projects need planning permission?
No — that is the point. What they need is proof, and that is the Lawful Development Certificate.
Route
Conditions
Time
What we do
1. Permitted development + Lawful Development Certificate
Rear dormer, L-shaped dormer or hip-to-gable within 40/50 m³; 3 m / 4 m rear extension; side return or side extension within half the house width and 4 m high
8 weeks for the certificate, run alongside the structural design
Check the house, draw the scheme to the limits, apply for the certificate and include it in the price
2. Prior approval (larger home extension)
Single-storey rear extension of up to 6 m (terrace or semi) or 8 m (detached)
42 days: neighbours have 21 days to object
Notify the council, manage the neighbour consultation, advise on the design to avoid a refusal on light
3. Full planning application
Mansards, wraparounds, two-storey rear extensions, anything on a flat, in a conservation area or on an Article 4 street
8–13 weeks after validation
Prepare and submit the application, with a pre-application where the borough is difficult
Building regulations & party walls
The other two approvals
Permitted development removes the planning application, not building control or the Party Wall Act. Every loft and extension needs building-regulations approval — the structure, insulation, fire safety, drainage and escape windows — which we do through LABC with full-plans drawings, so the inspector has agreed the design before work starts. On a terrace or semi the work touches the party wall, so notices go to the neighbours two months before the start; if a neighbour dissents, a surveyor is appointed and the award follows.
A Lawful Development Certificate is not compulsory, but a buyer's solicitor will ask for it when you sell. We apply for one on every permitted development project and include the council fee in the price.
Recent permitted development projects
Bohun Grove, East Barnet EN4 — rear extension, hip-to-gable loft and whole-house renovation
LABC 2024 Best Residential Extension in London
Semi-detached family home One programme loft + extension + renovation
A total renovation of a family semi: a rear extension opening into a full-width kitchen and dining space with floor-to-ceiling glazing and skylights, a hip-to-gable loft conversion with a rear dormer, two Lusso Stone bathrooms, enlarged bedrooms, new windows throughout, a regulated outbuilding and landscaping.
Because the loft and extension ran under one contract, the steelwork for the open-plan ground floor and the loft floor was designed together and lifted in on the same day — one crane hire, one scaffold, one building-control file.
See the Bohun Grove project · All projects
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ANDERSON · FOUNDER, LCCL CONSTRUCTION
Anderson's advice: permitted development is not the same as no neighbours
Semi-detached hip-to-gable and rear dormer combinations almost always fall under permitted development, but neighbours often object informally — to the council, to the inspector, to you. The certificate settles the planning question; it does not settle the party wall agreement, and a neighbour who first hears about your loft from a surveyor's letter takes their time signing. We knock on the door before the notice goes through it, and we serve the notices the day the certificate is applied for so the two clocks run together.
How a permitted development project runs with LCCL
From the first call to the completion certificate. Design, the certificate and building regulations typically take 8–12 weeks before work starts; the scaffold goes up on day one.
WEEK 0
Free consultation call
A 30-minute phone call with our team about the house, what you want from the space and a realistic budget. Your instant estimate is the starting point.
WEEKS 1–4
Survey, PD check & design
Measured survey, the permitted development check (allowance, conservation area, Article 4), concept drawings and the fixed price for the scope on the drawings.
WEEKS 4–12
Certificate, structure & building regulations
Lawful Development Certificate application (eight weeks), structural calculations, full-plans submission to LABC, party wall notices served.
ON SITE
The build
4–6 weeks for a Velux loft, 6–8 for a rear dormer, 8–10 for a hip-to-gable or L-shaped loft, 8–12 for an extension. Weather-tight in the first fortnight.
HANDOVER
Inspections & certificate
LABC completion certificate, the Lawful Development Certificate in your file, 12-month workmanship guarantee and 10-year LABC structural warranty.
“We are very pleased to have used Lccl Construction to do full house renovation and loft conversion to our edwardian terraced house. Project involved total strip out of interiors and remodelling repositioning the interior walls, electrical and plumbing…”
neil smith · Trustpilot
“We did a 3x10m single storey rear extension with LCCL recently. It was scheduled to take 12 weeks to complete but with Alex's experience and agile project management, we are ahead of schedule (finished in 10). Alex, and LCCL,is extremely knowledgeable and…”
Galichet Christophe · Google Reviews
“Hired LCCL Construction to design and build us a rear house extension. Found them easy to work with and are pleased with the results. They have been recommended to us for the whole build including designs and construction. The rear extension feels amazing,…”
James Grimsdale · Google Reviews
Permitted development questions
On a house: a rear dormer, L-shaped dormer or hip-to-gable loft within 40 m³ (terrace) or 50 m³ (semi or detached); a single-storey rear extension of 3 m (4 m detached); a side return or side extension no wider than half the house and no higher than 4 m; a garage conversion; a garden room. Flats, conservation areas and Article 4 streets are the exceptions.
The council's written confirmation that the work is lawful without planning permission. Not compulsory, but a buyer's solicitor will ask for it when you sell. We apply for one on every permitted development project and include it in the price; the council has eight weeks to issue it.
At economy specification: Velux loft from £32,400, rear dormer from £56,400, L-shaped dormer from £58,800, hip-to-gable with rear dormer from £60,000, 3 m rear extension or side return from £42,000 — all inc. VAT with the ex-VAT figure shown on the page. Postcode dependent; fixed for the scope on the drawings.
Shell and plaster with a sound, simple finish: standard windows and doors, standard insulation to building regulations, plastered walls ready for paint, first and second fix electrics and plumbing. Kitchen units, bathroom fittings and floor coverings are priced as separate lines; a higher finish level is agreed on the call.
Yes. The loft falls under Class B and the extension under Class A, so the allowances do not add together. We design and engineer both at once and the scaffold goes up once. A rear and a side extension in the same scheme is different — that is a wraparound and needs planning.
Yes to both. Permitted development only removes the planning application. We submit full plans to LABC and serve the party wall notices two months before the start.
8–12 weeks of design, certificate and building regulations, then 4–12 weeks on site depending on the project. Most permitted development projects are finished within five months of the first call.
We tell you on the call, before any drawing. Then it is a planning application — a mansard, a wraparound, a two-storey extension or a conservation-area scheme — and we handle that under the same contract.
Where we build permitted development projects
From Finchley N3 we cover North London, North-West London, Central London, South-West and West London, and Hertfordshire — and we also work across the rest of London, Buckinghamshire, Surrey, Kent and Essex. The 1930s semis of Barnet, Enfield, Harrow and the Hertfordshire towns are hip-to-gable country; the Victorian terraces of Haringey, Waltham Forest and South London are where the L-shaped dormers and side returns go.