Planning drawings for a Willesden house cost £645 drawings + £150 survey (£795 total) with our complete planning drawing service, for an extension or a loft conversion that needs an application. That covers the survey, existing and proposed drawings, the application pack and submission to Brent. Brent's householder fee of £548 is paid to the council. If you want to split a house into two flats, our house to two flats drawings cost from £945 drawings + £150 survey (£1,095 total), and that is a full application with a higher council fee of £610.
On this page
Which of those you need is the first question in Willesden. Its large late Victorian and Edwardian houses are often extended, and just as often someone wants to divide them.
Can I convert my Willesden house into flats?
Only if it passes Brent's test. Policy BH11 of the Brent Local Plan protects family homes of 3 bedrooms or more. It allows one to be split into two or more homes only when all three criteria are met (Brent Local Plan):
- Size. The existing home is 130 square metres or more, or could acceptably be extended to that size.
- A family home kept. The scheme still includes at least one home of 3 bedrooms, preferably with direct access to a garden.
- Transport. The site is in an area of public transport accessibility level (PTAL) 3 or above.
The plan says the 130 square metres can count extensions you could still build under permitted development or under Brent's extensions guidance. So a house just under the threshold may qualify once a rear extension or loft is drawn into the scheme. Policy BH13 then asks for private garden space: normally 50 square metres for a family home on the ground floor, and 20 square metres for other homes.
There is a narrow exception. Brent may accept smaller flats where the house is so poor for family life that it could not reasonably be put right. A lack of garden alone does not count.
Our drawings show the floor area sum, the family flat with its garden and the bin and cycle stores. Our converting a house into flats guide explains the London-wide space standards.
What about a house in multiple occupation?
That is a separate route. Brent's Article 4 direction on small HMOs has applied since 1 November 2022 in the areas on the council's map. Inside those areas, turning a family house into a small shared house needs planning permission. Our Brent HMO page covers it.
Is my Willesden street in a conservation area?
Possibly, and more streets may be added. The Willesden Green conservation area was designated in January 1993. Brent's December 2024 appraisal says it was largely built between 1881 and 1906, after the Metropolitan Railway opened. Today it covers the Victorian shopping streets of the High Road, the south side of Walm Lane, the top of Willesden Lane, and a small residential area called Heathfield Park (Willesden Green appraisal).
The appraisal proposes to extend it to residential streets built for the Willesden Park and Brondesbury Park estates, including Chatsworth Road, Dean Road and Brondesbury Park. It also notes that the area has no Article 4 direction yet, which has left the houses open to harmful changes. A direction is proposed for both the existing area and the new parts. Brent's conservation page now lists a non-immediate Article 4 direction for Willesden Green.
Once a street is in, the appraisal lists what needs permission: front windows and doors, painting the front, paving the front garden, roof tiles, chimneys and sheds. If you live on one of those streets, we check the current position before we draw. Nearby Mapesbury and Brondesbury are separate conservation areas with their own rules. In any of them, Brent asks for a heritage statement with the application, and for door or window replacements it wants window elevations normally at 1:10 and sections normally at 1:5. Those details take longer to draw than a standard set, so we price them at the quote stage rather than guessing.
What will an extension or loft look like on paper?
For a Willesden house outside a conservation area, Brent's January 2025 extensions guidance sets the numbers:
- Single-storey rear extension. Up to 6 metres on a terrace or semi, 8 on a detached house, and never more than half the garden.
- Two-storey rear extension. Up to 3 metres on a terrace or semi.
- Rear dormer. Up to the full width of the original roof, at least 0.2 metres above the eaves.
These figures come from the Brent SPD. Many Willesden houses have long rear outriggers. The SPD says an L-shaped dormer over one must not extend over more than half the outrigger's depth.
Brent asks for site photographs and a landscape plan with every householder application. Its decision target for minor applications is 8 weeks. Our Brent house extensions page and Brent loft conversions page go into more detail.
What do the drawings cost in total?
- Extension or loft: £645 drawings + £150 survey (£795 total), plus Brent's £548.
- House to two flats: from £945 drawings + £150 survey (£1,095 total), plus Brent's £610.
- Planning, building regs and structure together for one extension or loft: from £1,245 drawings + £150 survey (£1,395 total) through our package.
A flat conversion also needs building regulations drawings for fire separation and sound insulation between the flats. We confirm at the quote stage what that adds.
An illustrative example, not a real job: a four-bedroom Edwardian house near Willesden Green station measures 118 square metres. On its own it fails the 130 square metre test. With a permitted rear extension and loft drawn in, it reaches the threshold, so the scheme can show a 3-bedroom ground-floor flat with the garden and a smaller flat above.
See also Kilburn loft drawings and Wembley extension plans, and our Brent page.
Frequently asked questions
What size does a Willesden house need to be to convert into flats? Brent's Policy BH11 asks for 130 square metres or more, or a house that could acceptably be extended to that size. The scheme must keep a 3-bedroom home and be in an area of PTAL 3 or above.
Is Willesden in a conservation area? The Willesden Green conservation area covers the High Road shops, part of Walm Lane and Willesden Lane, and Heathfield Park. Brent's December 2024 appraisal proposes adding Chatsworth Road, Dean Road and Brondesbury Park.
Does a small HMO in Willesden need planning permission? In the areas on Brent's map, yes. Its Article 4 direction on small HMOs has applied since 1 November 2022.
Are Brent's fees included in your price? No. Council fees are paid to Brent at submission and shown separately on our quote.
If the application goes through the Planning Portal, the Portal adds its own service charge: nothing, £99 or £149 including VAT, depending on the application type and complexity, paid to the Portal at submission and not normally refunded with a council fee (Ashford Borough Council, Planning Portal service charges, 11 September 2026). It is not ours and not the council's. Other submission routes exist; where your council accepts one without a charge, we can use it.
