Extension plans and drawings across Bath
For Bath homeowners we handle extension plans and drawings, with fees agreed in writing before any work starts.
- Guide price in BathFrom £1,200 inc VAT
- PlanningWe find the right route for you
- Timescale2–6 weeks for drawings
- Postcode districtsBA1, BA2
Design and approval fees for Bath
Guide fees for Bath including VAT, using our South West England factor of ×1.02. Council and building control charges are not included.
| Option | What it covers | Guide price |
|---|---|---|
| Essential | Measured survey and planning drawings | £1,200 – £2,250 |
| Standard | Planning drawings plus building regulations drawings | £2,200 – £3,900 |
| Premium | Full pack with structural calculations and 3D visuals | £3,450 – £5,650 |
Try the guide-price tool to see a range for your own size and finish.
Do I need planning permission in Bath?
In England the main routes are permitted development (ideally confirmed with a lawful development certificate, £274), larger home extension prior approval (£249, 42 days) and a householder planning application (£548, normally 8 weeks), with council fees as set from 1 April 2026.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Included in a typical project
- Two or three layout options to compare
- 3D views to check the look and the light (full pack)
- Planning drawings: existing and proposed plans and elevations, site and location plans
- Measured survey of the house and garden
- Structural calculations from an engineer (full pack)
The most expensive changes are the ones made after the steel is ordered. A good design stage settles layout, heights, glazing and services on paper, so the build price is firm.
Working in Bath
Site visits are available across Bath (BA1, BA2). We also work in nearby Keynsham (6 miles), Frome (10 miles), Nailsea (18 miles), Portishead (19 miles).
In the South West, local stone, render and brick vary from town to town, so matching materials is a big part of designing an extension that looks right.
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions answered
How long does this take for a Bath home?
2–6 weeks for drawings, depending on the council and the complexity of the project.
Will my neighbours in Bath be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do you cover all of Bath?
Yes. We cover Bath and the surrounding parts of Somerset. Site visits are free and there is no obligation.
How much do extension plans cost?
Our design packs range from about £1,200 to £5,650 including VAT, from planning drawings only to a full pack with building regulations drawings, structural calculations and 3D views. Council fees are separate.
Can I use your drawings with another builder?
Yes. Once paid for, the drawings are yours to use for your project.
Book a free site visit in Bath
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.