We have written a couple of articles recently that reference Permitted Development and, for the super motivated, there is a 50-page document published by the Ministry of Housing, Communities and Local Government on the GOV.UK website. It’s hardly light reading, though, so we’ve done our best to explain the main points in user-friendly terms.
The basic rule
Permitted Development (PD) rights apply primarily to the rear and sides of your property. You almost never have PD rights to extend beyond the “principal elevation” (usually the front wall facing the road).
Furthermore, if your property sits on “Article 2(3) designated land“, which includes Conservation Areas, Areas of Outstanding Natural Beauty, and National Parks, or if it is a Listed Building, your PD rights are significantly restricted or completely removed.
Rules by extension type
1. Single-storey rear extensions
Under standard PD, you can extend beyond the original rear wall by up to 3 metres for terraced or semi-detached houses, and up to 4 metres for detached. (Note: Under the ‘Prior Approval’ neighbour consultation scheme, these limits can double to 6 metres and 8 metres respectively, provided adjoining neighbours do not object).
Height Limits: The maximum overall height for a single-storey rear extension is 4 metres. However, if the extension sits within 2 metres of a boundary wall, the maximum eave height drops to 3 metres.
2. Two-storey rear extensions
Two-storey extensions are permitted under PD, subject to tighter criteria – they cannot extend beyond the original rear wall by more than 3 metres, they must sit at least 7 metres away from the rear boundary opposite the wall being extended, and the roof pitch must match the existing house as closely as possible.
3. Side extensions
Side extensions must be single storey only, with a maximum height of 4 metres, and cannot exceed 50% of the width of the original house. Note: side extensions are not permitted on designated land under PD.
4. The 50% coverage cap
Across all extension types, the total ground area covered by extensions or outbuildings cannot exceed 50% of the total garden/curtilage space surrounding the original house (as it stood on 1 July 1948 or as originally built).
“Permitted” does NOT mean unregulated!
Even if your project falls neatly within PD rules, two critical obligations remain:
Building Regulations: PD only bypasses planning permission. Your build must still comply with strict UK Building Regulations covering structural safety, thermal insulation, drainage, and fire safety.
Lawful Development Certificates: We always advise applying to your local council for an LDC before building under PD. This legal document proves your extension was built legitimately under PD rules, preventing delays if and when you sell the property.
Looking for expert advice?
Navigating planning constraints requires a trained eye. Charles Clarke & Son works closely with leading local architects and planning consultants across Suffolk to ensure your project achieves its full potential safely and legally.
If you’re putting serious thought into extending a Suffolk property, please get in touch, we’ll be happy to discuss.
