Permitted development, explained
What permitted development rights cover for extensions, lofts and outbuildings, and the limits that most often catch homeowners out.
What permitted development means
Permitted development is a set of national limits that define what you can build without submitting a planning application. Your project still has to comply with building regulations, and other laws (party walls, covenants, listed building consent) still apply.
Rights can be removed on your property, for example in a conservation area, through an Article 4 direction, or on flats and maisonettes. Always check the specific property, not just the postcode.
Extensions: the limits people miss
Rear extensions have maximum depth rules that differ for detached and attached houses. Height, eaves height, and proximity to the boundary all count. If you have already extended the rear, previous work can eat into your remaining allowance.
Side extensions are tighter: on many house types only a single storey is possible under PD, with width and height caps. Wrap-around schemes that combine rear and side often push you into full planning.
Materials on elevations facing a highway sometimes need to match the existing house. That is a detail that catches people who assume “rear only” means any cladding.
Lofts, garages and outbuildings
Loft PD allows additional roof volume within a calculated allowance. Dormers on the principal elevation facing the road usually need permission; rear and side dormers may be OK if volume and height limits are met.
Converting an attached garage into living space is often PD if the structure stays within the original envelope. Detached garages converted or replaced can be trickier.
Outbuildings must be behind the principal elevation, within overall size limits for the curtilage, and not forward of the house. Height drops if you build within 2 metres of a boundary. “Garden offices” that are really annexe accommodation can be treated as dwellings, so planning is required.
Why we still document PD properly
Builders and building control need clear drawings whether or not planning was required. An LDC gives written proof from the council. We design to PD limits where that is the right route, and we flag early when a full application is safer for your goals.