Planning
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Do I need planning permission?

A free planning checker by Mayfair Studio - expert loft and extension drawings for London homes. Fixed-price architectural drawings with unlimited revisions, no hidden fees. Check your property against planning records, constraints and local policy in 2 minutes, then we handle the drawings and application.

Check now

Drawings are £1,880 all-in, fixed for a standard loft or extension - design, planning application, survey, building regs and structural calculations. Price match guarantee. See pricing

Buying rather than building? Pro report - a pre-purchase planning appraisal in 24 hours.

20 million+ UK planning applications on file, 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

33 live now

Loft conversion

In progress

Rear dormer with en-suite - Walthamstow, E17

Permitted Development
Build cost£58,000
Our fee£1,880

Rear extension

Contract sent

4m single storey with roof lantern - Tooting, SW17

Permitted Development
Build cost£54,000
Our fee£1,880

Side return extension

In progress

2.1m x 6.5m with skylights - Leyton, E10

Permitted Development
Build cost£46,000
Our fee£1,880

Two storey extension

Submitted

Rear 3m over two floors - Croydon, CR2

Planning Permission
Build cost£96,000
Our fee£1,880

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
33projects live right now

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

Why homeowners choose us

Fixed-price drawings and planning services that save you time and money.

Start in days, not weeks

No survey appointment needed to begin - we design from planning records, property data and your photos.

Designs in 2 weeks

First draft drawings delivered within 14 days of instruction.

Unlimited changes

We revise until you're happy. No extra charges, no compromise on your design.

Engineering included

Structural calculations are in the fixed fee. No separate engineer's bill.

Complete drawing set

Planning, building regulations and builder-ready drawings - all in one package.

Full planning support

We prepare, submit and manage your application. No paperwork, no planning stress.

Fixed prices. No surprises.

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

PackagePrice

All-in design & planning package

Loft conversion, rear/side/wrap-around extension, or two-storey extension

£1,880

Custom project

New builds, basements, listed buildings, change of use, complex projects

From £2,495

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

Our drawing services

Everything you need from survey to approval, all under one roof.

Loft conversion drawings

Dormer, hip-to-gable, L-shaped and mansard designs that maximise headroom and light. Structural calculations included.

Loft drawings

House extension drawings

Rear, side return, wrap-around and two-storey extensions. Builder-ready plans that blend with your existing home.

Extension drawings

Building regulation drawings

Complete technical drawings and calculations for building control approval. Exact specifications your builder can price and build from.

See pricing

Planning permission drawings

Full application prepared, submitted and managed for you, with council queries and amendments handled free of charge.

See pricing

How it works

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

Phase 1 · Months 1–3

Planning and approvals

Existing drawings - from records and photos1 week
Proposed design1–2 weeks
Planning submission and liaison8–10 weeks

Phase 2 · Months 4–6

Building regulations

Measured survey(Included)1 week
Building regs drawings3–4 weeks
Structural calculations(Included)10–12 days
Party wall notices(Included)1–2 weeks
Builder introductions4–6 weeks

Ready to check your property?

Start with a free AI check. If your project fits the standard package, the price is £1,880 all-in - no quote needed.

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 a fixed £1,880 all-in 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?
£1,880 all-in, fixed, for a standard loft conversion or extension - covers survey, drawings and planning support. Paid in two stages: £1,180 through to planning submission, £700 for building regs and structural calcs once approved. £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.