A visual guide to Permitted Development

In many cases, a garden room can be built without the need to apply for Planning Permission, as long as the building complies with the height and positioning rules laid out by Permitted Development.

The Government’s Planning Portal states these rules in list form, and whilst they are easy to understand, and are the definitive reference point, we thought it would be useful to add some garden room images to them!

This article should only be used as a guide and is not a definitive source; you can find that on the Planning Portal. It is your responsibility as the house owner to check if you need to apply for Planning Permission to build a garden room before you start work – in the worst-case scenario you can be made to take down the building!

It’s worth noting that the Planning Portal refers to buildings like garden rooms as outbuildings.

We will go through each rule as they are stated on the Planning Portal website.


No outbuilding on land forward of a wall forming the principal elevation.

You can’t build a garden room beyond the front wall of your house under Permitted Development. This means if you want to put a garden room in the front garden of your house you will need to apply for Planning Permission to do so.

Garden office permitted development 1 800 x 400


Outbuildings and garages to be single storey with maximum eaves height of 2.5 metres and maximum overall height of 4 metres with a dual pitched roof or 3 metres for any other roof.

This rule is telling us several things:

1) The garden room must be single storey. If you want to build a two storey garden room you will need to apply for Planning Permission.

2) This rule is also telling us that a dual pitched roof garden room should be no higher than 2.5 metres at the eaves and no taller than 4 metres at the ridge. Garden rooms with this shape roof need to be sited more than 2 metres from each boundary.

Dual Permitted Development 640 x 480

3) Single sloped roof garden rooms, also known as mono pitch roofs, can be no taller than 2.5 metres at the eaves and 3 metres at the ridge to comply with Permitted Development rules. They should also be sited more than 2 metres from each of your garden’s boundaries.

Mono Permitted Development

Maximum height of 2.5 metres in the case of a building, enclosure or container within 2 metres of a boundary of the curtilage of the dwelling house.

If you want to place your garden room within 2 metres of any boundary, i.e. your fence wall or hedge, it can be no taller than 2.5 metres high. In most cases this dictates a flat roof garden room.

Flat Permitted Development 640 x 480

No verandas, balconies or raised platforms.

This rule is saying that you can’t add a veranda, deck or balcony to your garden room under Permitted Development. However, the page for Permitted Development rules for decks says they can be built under Permitted Development as long as they are no higher than 300mm (1ft) and when combined with other structures don’t cover more than 50% of your garden.

Here is the wording:

Putting up decking, or other raised platforms, in your garden is permitted development, not needing an application for planning permission, providing: The decking is no more than 30cm above the ground together with other extensions, outbuildings etc., the decking or platforms cover no more than 50 per cent of the garden area.

Deck Permitted Development 640 x 480

No more than half the area of land around the “original house” would be covered by additions or other buildings. The term “original house” means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.

You may already have additions to your house like conservatories and sheds, greenhouses and decking. These buildings combined with the garden room should not cover more than 50% of your garden.

If you live in a Listed Building, within a National Park, in an Area of Outstanding Beauty, The Broads or a World Heritage site you WILL NEED TO APPLY FOR PLANNING PERMISSION TO BUILD A GARDEN ROOM.

We have always found the Planning Department to be helpful, and it’s worth having a chat with your local planning office before you decide on a garden room to check your individual position in regards to Planning Permission.

You could make a Pre Planning application or apply for a Certificate of Lawfulness to ensure your building applies with the Permitted Development rules. There is a cost involved in this, but it’s worth it for the peace of mind.


Visit the Garden Spaces websiteVisit the eDEN Garden Rooms websiteVisit the Gembuild website for garden offices & studiosVisit the Harrison James websiteFind out more about Green Studios Visit the Booths Garden Studios websiteVisit the Timeless Garden Rooms website Visit the Smart Garden Offices websiteVisit the Hideouts websiteVisit the ModBox Spaces websiteVisit the My Eco Space websiteSee what a garden room will look like in your garden