Garden Room Life

Home / Garden rooms in Devon

Garden rooms in Devon

Updated 22 October 2026

A desk and two stools set up on a garden patio

The short answer: the national rules for England apply in Devon, but more than a third of the county is protected. Dartmoor and Exmoor national parks and five National Landscapes together cover 35% of Devon.1 On that land you can't build a garden room to the side of the house, and buildings more than 20m from the house can cover no more than 10m² in total.2 Inside Dartmoor or Exmoor, you deal with the national park authority, not the council. And a garden room you plan to let to holidaymakers needs planning permission.

Planning permission in Devon

Garden rooms count as outbuildings. Most can be built without planning permission if they sit behind the front of the house, have eaves no higher than 2.5m, and together with other buildings cover no more than half the garden. If any part of the room is within 2m of a boundary, the whole building must be no more than 2.5m tall; otherwise the limit is 4m with a dual-pitched roof, or 3m for any other roof. It must be single storey, with no veranda, balcony or raised platform over 30cm.3 In the grounds of a listed building, any garden room needs permission, and so does a room used as primary living space, such as a bedroom.4 Our planning permission guide explains every rule.

Protected land in Devon

On designated land, which includes National Landscapes (the new name for Areas of Outstanding Natural Beauty) and conservation areas, you can't build a garden room to the side of the house without permission.5 In a National Landscape, national park or World Heritage Site, buildings more than 20m from the house can also cover no more than 10m² in total.3

Dartmoor and Exmoor

Inside a national park, the national park authority is the planning authority. Dartmoor National Park Authority says permitted development rights are different in national parks. Its guidance says you'll generally need permission for a garden building in front of the house, to the side of it, or over 4m to the ridge, and that within 2m of a boundary it must be no more than 2.5m tall.16 If you're unsure, it suggests applying for a certificate of lawfulness. Exmoor National Park Authority handles applications in the Devon part of Exmoor.7

Garden rooms as holiday lets

Parts of Devon have some of the highest rates of holiday homes in the country. South Hams has the highest rate of holiday homes of any council area in England and Wales outside the Isles of Scilly, and around Salcombe, Malborough and Thurlestone it's 171.9 per 1,000 homes.17

That makes this point important: permitted development only covers garden rooms used for purposes incidental to your home, like an office, gym or studio. It doesn't cover self-contained living accommodation or any other change of use.2 A garden room let to visitors, or one someone lives in, needs planning permission. Talk to the council or national park authority before you build one with that in mind.

Conservation areas

Each council designates its own. East Devon has 3318, Mid Devon 5119, North Devon 41 outside Exmoor20 and Torbay 24, where two conservation areas, Churston and Polsham, also have Article 4 directions.21 Mid Devon lists an Article 4 direction for Cullompton.19 If you're in one of these areas, check whether the direction covers garden buildings.

Building near the coast

East Devon's draft local plan introduces Coastal Change Management Areas, where development will only be appropriate if it has wider sustainability benefits and is safe over its lifetime.22 If your garden is on an eroding stretch of coast, ask the council how this applies before you commit to a permanent base.

Which council to ask, and the 2028 change

Planning in Devon is handled by the eight district councils (East Devon, Exeter, Mid Devon, North Devon, South Hams, Teignbridge, Torridge and West Devon), Plymouth and Torbay councils23, and the two national park authorities inside the parks. In July 2026 the government chose four new councils to replace them: an expanded Plymouth, a new Exeter council, an expanded Torbay, and a Devon Coast and Countryside council for the rest of the county.24 They're due to take over on 1 April 2028.25 Until then, apply to your current council.

Building regulations

Building regulations don't normally apply to a garden room under 15m² with no sleeping accommodation, or one of 15m² to 30m² with no sleeping accommodation that is at least 1m from every boundary or built mostly of non-combustible materials.26 Running a new electrical circuit to it is notifiable work, so use a registered electrician. See our building regulations guide.

What a garden room costs in Devon

Installed garden rooms typically cost £1,200 to £2,500 per m² across the UK27, so a 4m x 3m room usually costs £14,400 to £30,000 before extras. One quote site puts a mid-range 12m² garden office in the South West at about £18,000 fully installed.28 Average home prices in August 2026 were £306,003 across Devon and £360,616 in the South Hams.29

Devon has plenty of room for one: 35.8% of homes in the Devon County Council area are detached, against 22.9% across England.30

Want this checked for your own garden? Get a free planning report: we look up protected land at your postcode and apply the rules to your plans.

Get my free report

Questions people ask

Do I need planning permission for a garden room in Devon?

Often not, if it meets the national size and height limits. But a third of Devon is a national park or National Landscape, where you can't build to the side of the house and buildings more than 20m from the house are limited to 10m² in total. Check your postcode with our free planning report.

Can I use a garden room in Devon as a holiday let?

Not without planning permission. Permitted development only covers uses incidental to your home, not self-contained accommodation or a change of use such as a holiday let.

Who do I ask if I live on Dartmoor or Exmoor?

The national park authority, which is the planning authority inside the park. Dartmoor's guidance says you'll generally need permission for a garden building in front of or to the side of the house.

Related guides

A small dark timber building beside a lawn and blue hydrangeasOther areasRules and costs in other parts of the UK. A small modern garden room with glass doors at the end of a fenced gardenFree planning reportCheck protected land at your postcode. A white timber garden building with French doors and a red roofGarden room costsReal prices by size, with a calculator.

Sources

  1. Devon County Council, National and UNESCO designations.
  2. Planning Portal, Outbuildings: planning permission.
  3. Planning Portal (England), Outbuildings: mini guide. Permitted development limits for outbuildings.
  4. Ministry of Housing, Communities and Local Government, Permitted development rights for householders: technical guidance.
  5. Planning Portal, Outbuildings. Designated land rules for outbuildings.
  6. Dartmoor National Park Authority, Basic factsheets.
  7. Exmoor National Park Authority, Exmoor Local Plan: spatial portrait.
  8. South Devon National Landscape, South Devon National Landscape.
  9. South Devon National Landscape, Planning.
  10. National Landscapes Association, East Devon.
  11. National Landscapes Association, North Devon.
  12. Tamar Valley National Landscape, Tamar Valley National Landscape.
  13. Blackdown Hills National Landscape, Blackdown Hills National Landscape.
  14. UK National Commission for UNESCO, Dorset and East Devon Coast (the Jurassic Coast).
  15. UK National Commission for UNESCO, Cornwall and West Devon Mining Landscape.
  16. Dartmoor National Park Authority, Do I need planning permission?.
  17. Office for National Statistics, More than 1 in 10 addresses used as holiday homes in some areas, June 2023.
  18. East Devon District Council, Conservation areas.
  19. Mid Devon District Council, Conservation areas.
  20. North Devon Council, Conservation areas.
  21. Torbay Council, Conservation area appraisals.
  22. East Devon District Council, Coastal change topic paper, October 2025. Supports the draft local plan.
  23. Devon County Council, Census 2021.
  24. Plymouth City Council, Four-council shake-up to reshape Devon's future, July 2026.
  25. Moretonhampstead Parish Council, Government announces local government reorganisation decision for Devon.
  26. Planning Portal (England), Outbuildings: building regulations. When building regulations normally apply to outbuildings.
  27. MyBuilder, Garden room cost price guide, updated 21 October 2026. UK price ranges for garden rooms, foundations, electrics, plumbing and fees.
  28. Less, Garden room cost, updated April 2026. A commercial quote site; its method isn't published, so treat regional figures as indicative.
  29. HM Land Registry, UK House Price Index England: August 2026, provisional figures published 21 October 2026.
  30. Devon County Council, Census 2021 report.