West London runs from the most restrictive planning authority in the country in Kensington and Chelsea to the wide interwar suburbia of Hillingdon and Harrow. The brief that works in one is refused in the other, so the borough determines the design before the design starts.
Seven, spanning the widest policy range in the capital. Kensington and Chelsea is overwhelmingly conservation area and among the most restrictive authorities in England, with a basement policy limiting excavation to a single storey under no more than half the garden. Hammersmith and Fulham is similarly designated across its Victorian terraces. Ealing, Brent, Harrow, Hounslow and Hillingdon are largely interwar suburban stock where permitted development remains usable.
Two further West London factors are worth planning around. Heathrow generates aircraft noise contours across Hounslow and Hillingdon that bring sound insulation requirements on habitable rooms, and public safety zones near the runway ends restrict what can be built at all. Separately, the Metropolitan Green Belt covers substantial parts of outer Hillingdon and Harrow, where extensions are assessed against disproportionate-addition tests rather than the usual householder policies.
| Application type | Statutory fee | Determination |
|---|---|---|
| Householder application (extension, loft, dormer) | £548 | 8 weeks |
| Full application — new dwellinghouse | £610 | 8 weeks |
| Lawful Development Certificate (proposed) | £274 | 8 weeks |
| Listed building consent | No fee | 8 weeks |
| Prior approval — larger rear extension | £249 | 6 weeks |
| Package | Fixed fee | Turnaround |
|---|---|---|
| Essentials — measured survey, existing and proposed plans | 14–20 working days | |
| Loft conversion package — survey, plans, sections, elevations | 14–20 working days | |
| Mansard / roof rebuild package | 18–24 working days | |
| Complete — planning plus building regulations drawings | 20–28 working days |
Fees are national, so a Kensington application costs the same £548 as a Hillingdon one. What differs is the supporting material: a designated property needs a heritage statement and a fuller design justification, and a basement scheme needs a structural method statement and often a construction management plan.
We cover Ealing, Hounslow, Hillingdon, Brent, Harrow, Hammersmith and Fulham, and Kensington and Chelsea. They range from the most restrictive authority in England to outer suburbs where permitted development covers most domestic work.
Subject to policy, and it is among the strictest in the country: excavation is generally limited to a single storey under no more than half the garden, with a structural method statement, a basement impact assessment and a construction traffic management plan required alongside the application.
It can. Aircraft noise contours across parts of Hounslow and Hillingdon bring sound insulation requirements for habitable rooms, and public safety zones near the runway ends restrict residential development outright. We check the designation at quotation stage.
Substantial parts of outer Hillingdon and Harrow are Metropolitan Green Belt. Extensions there are assessed against whether they are a disproportionate addition to the original dwelling, which is a different and stricter test than the usual householder design policies.
Before you commit, it is worth understanding what it costs and seeing why homeowners choose us. You can search the site 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.
