Garden room, garden office, shed or outbuilding — find out in under 2 minutes.
This tool provides general guidance based on national permitted development rules only. It does not constitute formal planning advice and does not replace a professional assessment from a Chartered Town Planner. Site-specific factors may affect the outcome.
What type of property is this for?
Permitted development rights for outbuildings only apply to dwellinghouses. Flats are excluded by law.
Where would the structure go?
Even though flats don't have permitted development rights for outbuildings, we'd like to understand your proposal so we can advise on the best route for a planning application.
What type of development are you considering?
Tell us a bit more so we can advise on the planning application route and likely prospects.
What are the approximate dimensions?
Don't worry if you're not sure yet — rough figures are fine at this stage.
Enter the postcode or address
Enter the property postcode and we'll automatically check the national planning constraint maps for conservation areas, national parks, listed buildings, Article 4 directions, Green Belt and other designations that affect permitted development.
Checking planning.data.gov.uk…
Are you aware of any planning designations or restrictions on your property?
The national dataset does not include all local constraints. Your property may be affected by designations not shown above — for example, conditions on the original planning permission removing permitted development rights, restrictive covenants, local conservation area boundaries, or Article 4 directions not yet in the national register.
This checker queries planning.data.gov.uk for nationally held constraint data. Not all local planning authority records are included. The results do not constitute formal planning advice. A Certificate of Lawful Development (CLD) is the only way to obtain formal confirmation from the council that your build is lawful.
Where on the plot will the structure be built?
This is one of the most critical factors. Structures forward of the principal elevation are not permitted development.
Size & distance from boundaries
Under Class E of the GPDO 2015, the maximum permitted height depends on roof type and distance from boundaries. The total area covered by outbuildings must not exceed 50% of the curtilage (the land around the original house).
The eaves height is the point where the wall meets the underside of the roof. If the structure sits on a raised platform, decking or base, include that in the measurement — measure from ground level up to the eaves.
The maximum height from ground level to the ridge, apex or highest point of the roof. For flat roofs this will be the same as the eaves height. For dual-pitched roofs the maximum is 4m; for any other roof type the maximum is 3m.
Will more than 50% of the garden remain as open space?
Include front, side and rear gardens. The total ground area covered by all outbuildings (excluding the original house) must not exceed 50% of the total curtilage.
Distance from the nearest boundary?
If any part of the structure is within 2 metres of a boundary, the maximum height is limited to 2.5 metres at the eaves.
What will the structure be used for?
Permitted development under Class E requires that the building is incidental to the enjoyment of the dwellinghouse — it cannot be a separate home or business premises.
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This tool provides general guidance based on national permitted development rules only. It does not constitute formal planning advice and does not replace a professional assessment from a Chartered Town Planner.
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