Planning
LiveFree AI planning check - tell us what you think

Do I need planning permission?

A free planning checker by Mayfair Studio - UK planning specialists. Check any property against planning records, constraints and local policy in 2 minutes. If you'd like us to handle the drawings and application afterwards, we can. Fixed fees from £1,295.

Check nowSite planning report - £395

Free check answers the basics. The pre-purchase site planning report (£395, 24 hours) covers verdict, build cost, sensitivity, CIL math and a 7-day action panel for auction buyers and developers.

20 million+ UK planning applications on file, across 417 planning authorities

Results checked against 20 million+ UK planning applications across 417 planning authorities

What you get

1

Planning route

Whether your project needs planning permission or qualifies as permitted development

2

Cost estimate

Realistic build costs based on your area and project type

3

Constraints check

Conservation areas, listed buildings, Article 4 directions and tree preservation orders

4

Next steps

What to do next, whether you need drawings, and what they cost

Recent projects

23 live now

Rear extension

Contract sent

5m single storey with roof lantern - Wandsworth, SW18

Prior Approval
Build cost£65,000
Our fee£1,295

Loft conversion

In progress

L-shaped dormer with en-suite - Hackney, E8

Permitted Development
Build cost£72,000
Our fee£1,295

Side return extension

In progress

2.4m x 6m galley with bi-folds - Lambeth, SE24

Permitted Development
Build cost£48,000
Our fee£1,295

Wraparound extension

Submitted

Side 1.2m + rear 4m - Hounslow, TW4

Planning Permission
Build cost£88,000
Our fee£1,795

Our fee from £795 · Build costs from £15,000

Includes drawings, application and submission

Mayfair Studio is a UK architecture practice specialising in planning approvals.

20m+UK planning applications on file
417planning authorities covered
23projects live right now

Every project starts with a free check. You only pay when you're ready to proceed.

Fixed prices. No surprises.

Traditional architects charge £3,000-£8,000. We deliver the same quality for less.

PackagePrice

Small extension

Single-storey rear or side return, up to 20m²

£1,295

Medium extension

Loft conversion or wrap-around, up to 40m²

£1,595

Large extension

Two-storey or basement, up to 60m²

£1,995

Custom project

New builds, change of use, complex projects

Quote

All packages include unlimited revisions, council liaison, and free resubmission if refused.

Get started

We'll call you within 24 hours to discuss your project

How it works

From first check to ready-to-build drawings, typically 3 to 6 months.

Phase 1 · Months 1–3

Planning and approvals

Measured survey1 week
Existing drawings10 days
Proposed design2–3 weeks
Planning submission and liaison8–10 weeks

Phase 2 · Months 4–6

Building regulations

Building regs drawings3–4 weeks
Structural engineering(Third party)10–12 days
Party wall notices(Third party)1–2 weeks
Builder introductions4–6 weeks

Ready to check your property?

Start with a free AI check. If you need drawings and planning support, we will quote you a fixed fee on the call.

Check now

Prefer to speak to someone?

hello@mayfairstudio.co.uk
07942 343 800
We reply within 2 hours during business hours

Frequently asked questions

Everything you need to know

Do I need planning permission for my extension?
It depends on your property type, location and the size of the extension. Most single storey rear extensions up to 3m (terrace/semi) or 4m (detached) fall under Permitted Development, meaning no planning application is needed. But conservation areas, Article 4 directions and flats have stricter rules. Our free checker gives you a definitive answer in 90 seconds.
How much does an extension cost in London in 2026?
Single storey rear extensions in London cost around £2,200–£3,200 per m² for build, plus £1,295–£1,795 for architectural drawings and planning support. A typical 20m² extension totals £45,000–£65,000 including VAT. Prime central London (Kensington, Chelsea, Westminster) runs 20–30% higher.
How much do you charge?
Fixed fees from £1,295 for drawings and planning support. £1,295 covers most Permitted Development and Prior Approval projects. £1,795 is for Full Planning applications. £2,495+ is for listed buildings, basements and new builds. Council application fees are paid direct to the council on top of our fee.
How long does planning permission take?
A Full Planning application takes 8 weeks from validation (statutory target). Prior Approval is faster at 6 weeks. Permitted Development does not need an application at all if you are eligible. Add 2–3 weeks for us to prepare drawings before submission.
Is the planning check really free?
Yes. No sign-up, no email, no payment required. You get the full report including PD eligibility, planning constraints (conservation area, Article 4, listed building, flood risk, TPOs), borough policy summary and recommended route. We only charge if you decide to appoint us to produce the drawings.
What is the difference between Permitted Development and Planning Permission?
Permitted Development (PD) is a set of national rules that let you extend without a planning application, as long as you stay within strict size and design limits. Planning Permission is a full application to the council, required when you exceed PD limits or your property has Article 4 restrictions. PD is faster and cheaper but more limited.
Do you work outside London?
Yes. Our AI planning checker covers all English local planning authorities using national planning datasets. For architectural drawings we work across London and the Home Counties (Surrey, Kent, Essex, Hertfordshire, Buckinghamshire). Further afield we handle it as a remote project with a paid site visit.
What happens after I submit my planning check?
You get the full report instantly, on screen, with no email gate. If you decide you want us to produce drawings we follow up within 2 hours during business hours to confirm scope, collect existing drawings or arrange a measured survey, and send you a fixed-fee quote. You do not pay until you sign.

Still have questions? Email us or start a free planning check.