You want something at the bottom of the garden. Maybe a proper workshop where you can actually spread out. A home office away from the noise of the house. A garden room where you can sit in winter with the heating on and still feel like you're outside. Or just a decent-sized shed that doesn't leak.
For most outbuildings in England, you don't need planning permission. Class E of the permitted development rules covers sheds, garden rooms, workshops, greenhouses, garages, summer houses, and any other building incidental to the enjoyment of your home. If it meets the height, position, and size conditions, you can build it without an application, without a fee, and without waiting 8-13 weeks for a decision.
A typical garden office of 3 metres by 4 metres gives you 12 square metres of usable space - enough for a desk, bookshelves, and room to stand up and think. Insulate it properly, add power and lighting, and it becomes a genuine working space rather than a glorified shed. A larger structure - say 5 by 4 metres - gives you 20 square metres, enough for a gym, a studio, or a workshop with space for serious equipment.
Even close to the boundary, you can build something substantial. A 2.5-metre-high garden room right against the fence can have a footprint as large as your garden allows (within the 50% curtilage limit). Move it more than 2 metres from the boundary and you can go taller - up to 4 metres with a traditional pitched roof.
All of this is possible without a planning application. The conditions are clear and specific.
12 square metres. A proper garden office. No planning application required.
The height of your outbuilding depends on two things: how close it is to the boundary, and what type of roof it has.
Height is measured from the highest natural ground level immediately adjacent to the building - not from any patio, decking, or raised surface you've added. On sloping ground, this means you measure from the high side. For detailed guidance on this measurement, see our outbuilding height near boundary guide.
Behind the principal elevation only. No outbuilding can be positioned forward of the front wall of the house. If your house faces the street, the outbuilding goes in the rear or side garden - never in the front garden. If your principal elevation faces a different direction (which happens on corner plots), the rule follows the elevation, not the street.
Single storey only. No mezzanines, no loft spaces, no internal upper levels. The building must be genuinely single storey.
Incidental use only. The building must serve a purpose "incidental to the enjoyment of the dwellinghouse." A home office, gym, workshop, studio, games room, or storage space all count. A self-contained flat, a separate dwelling for a family member, or a commercial premises that operates independently from the house does not. The test is whether the use is connected to and subordinate to the house itself.
The "incidental use" question
Can you sleep in a garden room? Can you run a business from it? The answer is nuanced. Occasional overnight use incidental to the house (a guest room) is generally fine. Using it as primary living accommodation - someone's permanent bedroom or a self-contained rental - is not incidental and would require planning permission. Running a business is usually acceptable if the primary use of the building remains incidental to the house and the business doesn't generate significant traffic, noise, or disturbance beyond what's normal for a residential area.
If you already know what you want to build, the free eligibility check takes about two minutes.
All buildings on your plot - every extension, outbuilding, garage, shed, greenhouse, and anything else that isn't the original house - must not cover more than 50% of the total curtilage area. This is cumulative. If you've already extended the house and built a shed, the new garden room adds to the total. If a previous owner built structures, those count too.
On a large garden, this is rarely an issue. On a smaller plot, particularly if you've already extended, the 50% limit can become the binding constraint before the height or position rules do.
If your property is in a conservation area, National Park, AONB, the Broads, or a World Heritage Site, outbuildings are still permitted development - but with an additional restriction. On designated land, the total area of ground covered by outbuildings positioned more than 20 metres from any wall of the house is limited to 10 square metres. Closer than 20 metres, the standard rules apply.
In practice, this means you can still build a reasonably sized garden room or workshop on designated land, but it needs to be within 20 metres of the house. For a garden over 20 metres long, anything at the far end is severely size-limited.
Flats and maisonettes - PD rights under Class E only apply to houses. Listed buildings - you need planning permission and listed building consent. See our listed buildings guide. Houses created through a change of use under certain GPDO classes - no PD rights. Any building forward of the principal elevation - always needs permission. Any building exceeding the height limits, the 50% curtilage rule, or any other Class E condition - needs permission.
If an Article 4 direction removes Class E rights in your area, you'll also need to apply.
Common mistakes that cost money
Thinking there's a maximum size. There is no maximum floor area for an outbuilding under Class E - only height limits and the 50% curtilage rule. A 30 square metre garden room is fine if the height and coverage limits are met.
Building in the front garden. Any outbuilding forward of the principal elevation needs planning permission, regardless of size.
Not accounting for all structures in the curtilage coverage. The 50% rule includes everything - extensions, garages, sheds, greenhouses, bike stores. Homeowners often forget smaller structures when calculating.
Using the building as a separate dwelling. A self-contained flat or permanent living space is not incidental to the house and requires planning permission and building regulations approval.
PD Assessment Tool
A professional permitted development assessment from a planning consultant typically costs £400-600 and takes 2-3 weeks. This tool checks your specific project against every Class E condition and produces a formal document you can share with your builder or your council.
The first step checks whether your property is eligible - about two minutes, completely free. If your property qualifies, the full project assessment is £47.
Content verified against the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended), Class E of Part 1, Schedule 2 (legislation.gov.uk, revised version) and the government's technical guidance (September 2019). Fees confirmed as of 1 April 2026. SI 2026/313 confirmed no changes to Class E. This page is for general information only and does not constitute legal advice.
April 2026