A disused Lewisham garage is already most of a bedroom, a study or the wider half of a kitchen-diner. Three pieces of work stand between: establishing the consent route, drawing a full building regulations set that satisfies Part L, and calculating the structure that replaces whatever comes out.
Usually not, if the garage is attached and no new opening faces a highway. Lewisham issued 1,221 lawful development certificates in three years, and the borough holds 89 Article 4 areas — the check that most often turns a certificate into an application.
| Measure | Lewisham | Outcome |
|---|---|---|
| Lawful development certificates issued | 1,221 | — |
| Article 4 areas in the register | 89 | — |
| Conservation areas | 30 | 705 hectares |
| Householder decisions | 2,037 | 86.3% approved |
| Certificate application fee | £274 | statutory, England 2026 |
| Building regulations package | from £840 | our fixed fee |
Sources: decision figures from MHCLG District Planning Application Statistics (PS1 and PS2), twelve quarters to March 2026; registers from the MHCLG Planning Data Platform, retrieved 1 September 2026; the fee from the Fees for Applications Regulations 2012 as amended; the package fee is our own published fixed fee. Building regulations apply to a garage conversion whether or not planning permission does: the floor, walls and any new opening all become new thermal elements under Approved Document L.
A garage conversion drawings package in Lewisham, where the stock is largely Victorian and Edwardian terraces across Brockley, is the full measured-survey-to-submission drawing set London Borough of Lewisham needs in order to determine an application: existing and proposed plans, elevations and sections at 1:100 and 1:50, a location and site plan, and the supporting statements the case officer asks for.
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Turn your unused Lewisham garage into a bedroom, home office or open-plan kitchen-diner. Planning route assessment, full building regulations drawings with Part L thermal compliance, structural calculations for any removed walls.
Housing stock in Lewisham: Victorian and Edwardian terraces across Brockley, Honor Oak, Forest Hill; 1930s semi-detached in Catford and Hither Green; post-war mixed in Deptford.
Character: Generally permissive planning compared to central boroughs; loft conversions and side-return extensions routinely approved under PD.
Before anything is drawn we settle whether the conversion needs planning permission at all; most integral garages do not. Getting that call right is what keeps an application from being pulled later, and Lewisham applicants pull very few. Of 4,408 applications reaching the council between 2023-24 and 2025-26, just 158 came back out again - a 3.6% withdrawal rate, set against 6.9% for the 33 boroughs pooled. A withdrawal is almost always an application heading for refusal, so a low rate points to schemes that were sound when they went in. Source: MHCLG live planning statistics.
The garage gets surveyed properly, along with whatever room it will open into once the dividing wall goes, so the drawings start from measured reality rather than from the estate agent's floor plan.
Existing and proposed sheets at 1:50 - floor plans, elevations, sections - specified to a standard Lewisham's validation team will accept without a request for further information.
The energy standard applies to the finished room, not to the garage it used to be: insulation added to floor, walls and roof, glazing U-values that comply, and heating designed for a space the existing system was never sized to serve.
Take out the garage door and something has to hold up what sat above it. We size that beam or lintel, specify the padstones under its bearings, and do the same for any internal wall coming out to join the garage to the house.
We lodge a Full Plans application with Lewisham Council's building control service, or with an approved inspector if your builder already works with one, then coordinate each inspection through to sign-off.
Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Move the controls for an indicative figure. It anchors your budget — it is not a quote. Every project is priced after a site survey.
Build costs are separate and quoted by your contractor. See our published fees.
The Lewisham postcode districts we draw in are set out below, with the housing each is largely built from and the council that validates a garage conversion there. Where a fee appears it is the 2026 statutory England application fee, not a build cost and not our charge.
| Postcode | Area | Dominant stock | What it means for a garage conversion |
|---|---|---|---|
| SE6 | Catford / Bellingham | 1930s semi-detached, post-war flats | Catford and Bellingham. Lewisham Council handles SE6. Interwar and early post-war estate housing dominates, and integral garages of that vintage are the simplest type to convert. |
| SE8 | Deptford | Georgian terraces, post-war estates, new-build | Deptford, SE8, falls to Lewisham Council. Garages are scarcer in this part of the borough, so where one exists it is worth checking whether it is genuinely integral before assuming permitted development. |
| SE12 | Lee / Grove Park | Victorian and Edwardian terraces across Brockley | Lee and Grove Park, SE12, is divided between Lewisham and Bromley. The postcode alone will not tell you which; the address does, and it has to be settled before submission. |
| SE13 | Lewisham / Hither Green | Victorian terraces, post-war flats | Lewisham and Hither Green. SE13 goes to Lewisham Council. Much of the housing is Victorian terrace with a later garage added at the side, which is a different structural proposition from an integral one. |
| SE14 | New Cross | Victorian and Edwardian terraces across Brockley | New Cross. An SE14 conversion is determined by Lewisham Council against its own Local Plan, and the dense terraced grain here means neighbouring windows are usually part of the assessment. |
| SE23 | Forest Hill / Honor Oak | Victorian villas, Edwardian terraces | Forest Hill and Honor Oak. Lewisham Council decides an SE23 garage conversion, and several of the hill streets here sit inside designated areas that constrain what the front elevation can become. |
| SE26 | Sydenham | Victorian villas, Edwardian terraces | Sydenham, SE26, crosses a boundary. Some addresses are Lewisham's and some are Bromley's, so confirm which council validates before drawings are prepared - the two apply different local policy. |
| SE3 | Blackheath / Kidbrooke | Georgian villas, Victorian terraces | Blackheath and Kidbrooke share SE3 between Greenwich and Lewisham. Neither policies map is authoritative on its own, so the address goes to both before we accept an assumption about who determines it. |
A garage on one Lewisham street and a garage on the next can support quite different schemes. Pitch, wall construction and the depth left behind the house all move the answer, so we design from what the survey found.
Conservation areas covering Lewisham: Lewisham Council runs 30, and Deptford High Street, Forest Hill, Hither Green are the ones Lewisham owners meet most. A garage conversion inside a Lewisham conservation area loses permitted development, so the Lewisham submission is a householder application at £548 decided in 8 weeks — not a £249 prior approval decided in 6 weeks. In Hither Green a garage conversion is judged on the street elevation first.
Article 4 and your Lewisham garage conversion: Lewisham Council has made no borough-wide direction, so permitted development for a garage conversion in Lewisham generally survives outside Lewisham conservation areas and listed curtilages. A Lawful Development Certificate at £274 is how a SE4 owner records that a garage conversion was lawful.
Lewisham housing stock: Victorian and Edwardian terraces across Brockley, Honor Oak, Forest Hill; 1930s semi-detached in Catford and Hither Green; post-war mixed in Deptford. Generally permissive planning compared to central boroughs; loft conversions and side-return extensions routinely approved under PD. Read that before choosing a garage conversion route in Lewisham — construction, not postcode, sets what is achievable. Lewisham Council charges £548 for a householder application and has 8 weeks to determine it.
Sources for this Lewisham garage 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.
Turning a garage or outbuilding into a living room is usually judged as a change of use, and in Lewisham 109 such decisions were pushed as far as an Inspector between 2016 and 2026. Most did not survive the trip: 28 allowed, 80 dismissed, 1 split. That works out at 25.7% succeeding, a little under the 29.1% across the capital. Appealing is not a strategy; it is what is left when the first attempt was wrong.
A Lewisham appeal takes a median 113 days from lodging to decision, and those weeks come after the council has already had the application. 96.3% ran as written representations, which means an Inspector read the case rather than heard it - so ambiguity in a drawing is never cleared up in conversation, it is simply weighed as it reads.
Based on the 109 change-of-use appeals the Inspectorate decided for Lewisham. Source: Planning Inspectorate appeal decisions, OGL v3.0.
What Lewisham owners ask us about garage conversion drawings, and the straight answer to each.
Start a free quote →Most integral garage conversions in Lewisham do not require planning permission — they're classed as an internal alteration, which is not development under the TCPA 1990. However, if the conversion materially alters the external appearance (new windows, raising the roof), planning permission may be required. Detached garage conversions to habitable use always need planning. Article 4 Directions in Lewisham may also affect eligibility. We confirm the planning route before quoting.
Per square metre, a garage is the cheapest habitable space a Lewisham house can gain: the floor, three walls and a roof already exist. Our fee covers working out the consent route, the building regulations drawings, and the structural design where the door was. On site, the variables are whether the garage is integral or standing on its own, and how far insulation, floor finishes and services have to be taken. Fees follow below.
It does, without exception - a garage becoming a habitable room is a change of use for building control, and Lewisham will want the full picture. Insulation and glazing sit under Part L; escape and fire spread under Part B; the old garage slab and its damp protection under Part C; airflow under Part F; and whatever now spans the door opening under Part A.
No honest percentage exists, so we will not invent one. What is on record is what Lewisham property changes hands for: the Land Registry's 2025 price-paid returns show a median sale of £470,000 across 3,101 transactions in the borough, the same median as 2024. A garage conversion is a modest spend against a number of that size, and the case for it is the room you get rather than a resale figure nobody can evidence. Source: HM Land Registry Price Paid Data.
Drawings take 3 to 4 weeks; the build on a standard integral garage runs 4 to 6 weeks once building control has approved. From first survey to a finished room, 3 to 4 months is a realistic total for a Lewisham project.
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