Planning permission for two-storey extensions in Dorset

Dorset at a glance

Nation: England
Price region: South West England
Postcode areas: BH, DT, SP
Towns covered: 16 listed below, plus surrounding villages
Site visits: Free, no obligation

What a planning application involves

This service suits you if you want your two-storey extension to go through planning with the best chance of approval. You get a check of your house's planning history, permitted development rights and local design guidance, a design shaped around them, the application prepared and submitted, and someone to deal with the planning officer's questions. We cannot promise an outcome, but we design to give the application a fair chance.

The main places we list in Dorset are Bournemouth (BH1), Poole (BH15), Weymouth (DT3), Christchurch (BH6), Ferndown (BH22) and Dorchester (DT1). We cover the villages in between too.

Fees

Planning drawings are a guide of £2,000–£3,500, priced in writing before the design stage starts. Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026).

Rules in England

In England, a householder planning application costs £548 (or £575 for applications made from 8 December 2026), and councils should decide within 8 weeks of validation. Two-storey side, wraparound and front extensions always need permission. Rear extensions may be permitted development within the 3 m and 7 m limits, confirmed with a lawful development certificate costing £274 (about £288 for applications from 8 December 2026).

Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.

Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.

The Party Wall etc. Act 1996 applies, so notices may be needed for work on or near a shared wall or boundary.

Getting the design right

Neighbours' light and privacy

The main concerns on a two-storey extension are usually loss of light, outlook and privacy for neighbours. We test the design against nearby windows and gardens, and adjust depth, roof shape or window positions before submitting.

Design to local guidance

Most councils publish guidance on extensions covering set-backs, roof heights, boundary gaps and neighbours' light. Designing to it from the start makes approval more likely and reduces the chance of being asked to make changes during the application.

How we work in Dorset

Free site visit
We visit your home in Dorset, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering Dorset.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Towns we cover in Dorset

Planning permission for two-storey extensions in Dorset: questions

What happens if my planning application is refused?

You can change the design and apply again, or appeal. In England, a householder appeal must usually be made within 12 weeks of the decision. Often the best route is a revised design that answers the reasons for refusal. We read the officer's report and advise which option has the better chance.

Should I get pre-application advice from the council?

It can help on sensitive sites, such as conservation areas, corner plots or front extensions, where the council's view is hard to predict. Many councils charge for it and response times vary. For straightforward designs that follow local guidance, a well prepared application is often the quicker route.

Neighbouring areas

All extension services in Dorset · About planning permission for two-storey extensions