Architectural drawings for an extension, done right. Fixed price.

2,000+ projects · 94% approval

We've completed 2,000+ extension projects for homeowners across England and Wales, with a 94% planning approval rate. Every set of drawings starts with a millimetre-accurate 3D Home Scan of your home, so nothing is guessed.

What you get in your extension plans

Your extension plans are a complete, council-ready set of drawings. Every package includes:

• Planning permission drawings — existing and proposed floor plans, elevations and site plans
• A permitted development check
• Council submission and chasing
• A build cost estimate

They're the same architect plans a traditional practice would produce. There's no legal requirement to use a RIBA-chartered architect for a house extension, so you get drawings that do exactly the same job — without the open-ended fees.

Architect, designer or technologist

Do I need an architect for an extension?

For most house extensions, no. There is no legal requirement to use a chartered architect for a house extension in England or Wales. Your council assesses the drawings, not the title of the person who produced them, so what decides your application is whether the plans are accurate, complete and show the planners what they need to see.

It helps to know what the word actually covers. “Architect” is a regulated title in the UK — the Architects Registration Board controls who may use it. That protects the title, not the task. Architectural designers and architectural technologists carry out the same work on an extension: the survey, the technical drawings, permitted development advice, the planning application, building regulations drawings and the coordination with a structural engineer.

So the honest answer is that a chartered architect is rarely the deciding factor on a straightforward rear, side or wrap-around extension. What you do need is someone who can produce a drawing set your council will accept, and who stays with you when the planners come back with questions.

Do I need an architect for planning permission?

No. Your council judges the drawings, not the person's title. What it expects is a consistent set — existing and proposed floor plans, elevations and a site plan, drawn to scale and matching the house as it really is. That last point is where applications most often come unstuck, which is why we scan the property in 3D before anything is drawn rather than working from hand measurements.

How to choose an architect or designer for your extension

Whoever you speak to, these are the seven things worth asking about before you commit:

1. A fixed price, confirmed in writing. Ask for the total, not an hourly rate that can drift.
2. Who actually does the work. An in-house team is easier to deal with than a chain of subcontractors.
3. Real completed projects. Ask to see finished extensions and what the owners said, not only renders.
4. What happens if planning is refused. A firm confident in its drawings will tell you plainly where it stands.
5. How long the drawings take. Ask for a timescale in writing. Ours are typically ready in around eight weeks.
6. Whether building regulations drawings are included. A low opening price often stops at planning and charges again for building regs and structural calculations.
7. Whether they can point you at builders. A vetted list saves you weeks of chasing quotes.

The warning signs run the other way: “from” prices with no total, no real projects to show, structural calculations quietly left out, slow replies, a process nobody will explain, and pressure to sign.

That's the standard we hold ourselves to. You get a fixed price confirmed in writing before we start, drawings produced in house, 2,000+ extension projects behind them and a 94% planning approval rate.

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Common questions

House extension drawings FAQs

Are these proper architect plans?

Yes. You get the same architect plans a traditional practice would produce — full planning drawings and, on our Standard and Premium packages, building regulations drawings and structural engineer's calculations too. The difference is the fixed price and the fixed timeline, agreed before we start.

Do I legally need a RIBA-chartered architect?

No. For a house extension there's no legal requirement to use a RIBA-chartered architect. Your council assesses the drawings, not the person's title, so what matters is that the plans are accurate and complete.

Is an architectural designer as good as an architect for an extension?

For extension work, yes. An architectural designer or architectural technologist covers the same ground — survey, planning drawings, permitted development advice, building regulations drawings and structural coordination. Judge any firm on its completed projects, its approval record and whether the price is fixed in writing, rather than on the title.

How long do the drawings take?

Planning drawings are typically ready in around eight weeks, then submitted to your council for you.

Do you work across England and Wales?

Yes. We work remotely with homeowners across England and Wales, so you get the same fixed-price service wherever your project is.

Extension guides

Extension guides

Not sure what your extension will cost, or whether it needs planning permission? These guides cover the questions homeowners ask us most, in plain English.

• How much does a 2 storey extension cost?→ Typical costs per square metre in 2026, worked examples at 30m² and 50m², and how two-storey compares with single-storey.
• Side return extension planning permission→ When a side or side-return extension is permitted development, the limits at a glance, and what changes for two-storey side extensions.
• Do I need planning permission for an extension?→ The size, height and position limits, when you must apply, and the Larger Home Extension route. Written for houses in England, with Wales flagged where the rules differ.
• Planning permission drawings→ What your council needs to see on the drawings, and how planning drawings differ from building regulations drawings.
• Party wall agreement explained→ When a rear or side extension needs a party wall notice, how long the two-month and one-month notice periods take, what it costs if your neighbour appoints a surveyor, and a free example party wall pack to download.