How much does it cost?

From £1,295 for our service. Build costs are separate and depend on your project.

How long does it take?

3-4 months from start to approved plans.

What if planning gets rejected?

We refund your fee if it's rejected due to our design.

Do you find builders?

We introduce you to good builders we know and trust.

What if I need changes during the design process?

Minor changes included in fixed price. Major scope changes may require fee adjustment, quoted transparently beforehand. We include 2 rounds of revisions before planning submission.

How do I know if my project is feasible?

Free feasibility check included before payment. We assess against London planning policies and local restrictions. If major issues found, we advise alternatives or recommend not proceeding.

What is included in your architectural service?

Our service includes measured survey, existing drawings, proposed design with 3D visualizations, planning application submission and management, building regulations drawings, structural engineering coordination, and builder introductions. Everything you need from concept to construction-ready plans.

How much do your services cost?

Our fixed-price services start from £1,295 for ground floor extensions, £1,595 for loft conversions, and £1,795 for first floor extensions. This includes all architectural drawings and planning application management.

How long does the process take?

The typical timeline is 4-6 months from start to planning approval. Initial designs take 2-3 weeks, planning applications typically take 8-10 weeks for determination, and building regulations drawings take 3-4 weeks.

Do you guarantee planning approval?

Yes, we offer a planning approval guarantee. If your planning application is refused due to our design, we provide a full refund of our design fees.

Which areas of London do you cover?

We provide architectural and planning services across all London boroughs and Greater London, including popular areas like Westminster, Camden, Islington, Hackney, Tower Hamlets, Greenwich, Wandsworth, and Richmond.

We design buildings

Plans, drawings and planning permission for any building project in London.

Get quote

Check Permitted Development Get total project costs

From £1,295 • Fixed price

Quick Check

Can you use Permitted Development?

See if your project qualifies and could save thousands in design and planning fees.

Check My Project

Instant resultsSave time & money

Cost Estimate

What will your project cost?

Get estimates for our design fees plus realistic construction costs from builders.

Get Project Estimate

Our design feesBuilder estimates

What are you building?

Choose your project type to get started with your quote.

Extension

From £1,295

Design service fee

First Floor

From £1,795

Design service fee

Loft

From £1,595

Design service fee

Other

From £1,295

Design service fee

Renovation

From £1,295

Design service fee

New Build

From £2,495

Design service fee

What we do

We design your extension and get planning permission.

Plans

We measure and draw what you want to build.

Permission

We submit to council and get approval.

Builders

We introduce you to good builders.

Project examples

Real projects with real costs.

Our Method

How we take you from first chat to ready-to-build plans.

Key:

Delivered by us

Delivered by third parties

Swipe left to see the full timeline →

Month 1

Month 2

Month 3

Month 4

Month 5

Month 6

Measured Survey

1 week

Measured Survey

1 week

We visit and measure your home precisely.

Existing drawings

10 working days

Existing drawings

10 working days

Creating detailed architectural drawings of your current property layout.

Proposed design

2-3 weeks

Proposed design

2-3 weeks

We draw your vision and show you what it looks like.

Planning support

8-10 weeks

Planning support

8-10 weeks

We deal with the paperwork. They usually say yes eventually.

CCTV drainage survey

1 week

CCTV drainage survey

1 week

Specialist inspection of existing drainage systems to inform construction plans.

Structural engineering

10-12 working days

Structural engineering

10-12 working days

Professional structural calculations to ensure your extension is safe and compliant.

Building regs drawings

3-4 weeks

Building regs drawings

3-4 weeks

All the boring technical stuff. Every window, every wall thickness.

Party wall notices

1-2 weeks

Party wall notices

1-2 weeks

Legal notifications for neighbors if your extension affects shared walls.

Building Control Approver's signoff

1 week

Building Control Approver's signoff

1 week

Building control makes sure it won't fall down.

Find a builder

4-6 weeks

Find a builder

4-6 weeks

We know the good ones. No cowboys, promise.

Questions

Let's talk

Ready to start your extension? Get in touch and we'll take it from there.

Call or WhatsApp

Chat about your ideas or get a quick answer.

+44 7405 920944

Call now WhatsApp

Email us

Send us your ideas, photos, or questions.

hello@multiply.build

Send email

Or get a quote online

Answer a few questions to get your project estimate.

Get quote