Serving Cardiff · Online

Home extension plans in Cardiff.

Arkiplan is an online architectural design service for Cardiff homeowners — the practical alternative to a traditional high-street architect. Planning drawings, building regs and structural work, designed with you over video and delivered at a fixed price.

Book a free design call
Fixed priceAgreed up front, no percentage fees
Cardiff & beyondRemote design, your local council
We handle planningSubmitted, chased and answered

Planning drawings & extensions in Cardiff

Cardiff’s housing runs from Victorian terraces in Cathays and Roath to interwar and suburban semis further out, where rear extensions and loft conversions are the most popular ways to add space.

Because Cardiff is in Wales, the Welsh planning system and separate Welsh building regulations apply. Notably, the England-only 6m/8m larger-extension scheme does not apply here, so larger rear extensions more often need a full application. We draw to Welsh standards and confirm your route up front.

Applications in Cardiff go to Cardiff Council, under the Welsh planning system. We draw to Welsh building regulations and confirm your permitted-development position for the address.

What we do for Cardiff homeowners

Whatever your project, it is designed and submitted the same simple way — from wherever you are.

What we design

  • Rear, side & wrap-around extensions
  • Loft conversions & dormers
  • Garden rooms & outbuildings
  • Garage conversions & new builds
  • Planning & permitted-development applications
  • Building regulations drawings & structural calculations

How it works from anywhere

  • One 3D Home Scan™ of your property — the only visit needed
  • Design on video with your designer, evenings included
  • We draw & submit planning and building-regs applications
  • We handle your council — queries, chasing, the decision
  • One fixed price, agreed up front from your free call

Cardiff planning & extensions FAQ

Do you cover Cardiff?

Yes. Arkiplan is an online architectural design service working across England and Wales, including Cardiff and the surrounding area. Your design is done over video, with a single 3D Home Scan of your property.

Which council handles my Cardiff planning application?

Applications in Cardiff go to Cardiff Council, under the Welsh planning system. We draw to Welsh building regulations and confirm your permitted-development position for the address.

Do I need planning permission for an extension in Cardiff?

It depends on the size and your property. Many single-storey rear extensions are permitted development, but Cardiff follows the Welsh planning rules, which differ from England — for example, there is no 6m/8m larger-extension scheme. We confirm exactly which route applies to your address before drawing anything.

Do you visit homes in Cardiff?

We arrange one 3D Home Scan of your property to capture it accurately. Everything after that — design calls, drawings and submission — is handled remotely, so you do not need to take time off for office visits.

How much does it cost in Cardiff?

The price is the same wherever you are — a single fixed price agreed up front, with no percentage-of-build-cost fees. Use the instant price tool for a tailored range in about 45 seconds.

Do you handle building regulations in Cardiff?

Yes — we produce building regulations drawings and coordinate structural calculations to Welsh standards, and submit to building control on your behalf.

Get your Cardiff project priced in 45 seconds.

No call required, no card required — just a tight, fixed-price range tailored to your project, with the planning route confirmed for your address.

Book a free design call

This page is general information, not planning advice. Permitted development and planning rules depend on your specific property and local authority and can change. We confirm the current position for your address as part of every project.