Planning permission for extensions in Harrow
For Harrow homeowners we handle planning permission for extensions, with fees agreed in writing before any work starts.
- Guide price in HarrowFrom £450 inc VAT
- PlanningWe find the right route for you
- Timescale8–13 weeks typical decision period
- Postcode districtsHA0, HA1, HA2, HA3, HA7
Design and approval fees for Harrow
Guide fees for Harrow including VAT, using our London factor of ×1.3. Council and building control charges are not included.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Permitted development confirmed in writing (certificate or notification) | £450 – £850 |
| Standard | Householder planning application handled | £750 – £1,450 |
| Premium | Application with heritage or design statements, and responses to the council | £1,150 – £2,100 |
Our handling fee only. Council fees are extra: in England from 1 April 2026 a householder application is £548, a lawful development certificate for a proposed extension £274 and a larger home extension prior approval £249. Drawings are priced separately.
For a figure based on your own dimensions, use our guide-price tool.
Planning rules that apply in Harrow
In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.
The planning position for a specific Harrow address depends on its history and any designations, which is why we check it at the first visit.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Who this service is for
- Projects in conservation areas or with previous refusals
- Homeowners who would rather not deal with the council themselves
- Anyone unsure whether their extension needs permission
A lawful development certificate is not compulsory for permitted development, but it is the cleanest proof that the extension was lawful when you come to sell. We usually recommend one.
Working in Harrow
We cover Harrow and the postcode districts HA0, HA1, HA2, HA3, HA7, HA9. Neighbouring towns we cover include Wealdstone (1 mile), Wembley (2 miles), Pinner (2 miles), Northolt (3 miles).
Just over the Hertfordshire border, Bushey is about 5 miles away. London's housing is dominated by Victorian and Edwardian terraces, many with a rear outrigger and a side return, and 1930s semis in the outer boroughs. Conservation areas are common, so the planning check comes first.
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Harrow home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Harrow, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does this take for a Harrow home?
8–13 weeks typical decision period, depending on the council and the complexity of the project.
Who do I contract with in Harrow?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
What happens if planning is refused?
You can revise the design and reapply, or appeal. We read the officer’s report and tell you honestly which option has a better chance.
How much does planning permission cost?
In England, from 1 April 2026 the council fee is £548 for a householder application, £274 for a lawful development certificate for a proposed extension and £249 for larger home extension prior approval. Our handling fee is separate.
Book a free site visit in Harrow
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.