The distinction between planning permission and Building Regulations approval is one that many homeowners find confusing, and the interaction between permitted development rights and Building Control is a common source of misunderstanding. The short answer is that permitted development relates to planning law and addresses whether a development is acceptable in land use and appearance terms, while Building Regulations relate to the technical standards of the building work itself. Having one does not give you the other.

Permitted Development and Planning

Permitted development rights allow certain types of work to be carried out without a planning application to the local authority. These rights are granted by the Town and Country Planning (General Permitted Development) Order and cover a wide range of domestic works including extensions within certain size limits, loft conversions that do not exceed specified dimensions, outbuildings within defined parameters, and changes of use in some circumstances. Where a project falls within permitted development rights, no planning application is required and no planning permission needs to be obtained.

Building Regulations Are Separate

Building Regulations approval is governed by separate legislation, principally the Building Act 1984 and the Building Regulations 2010. Whether a project requires Building Regulations approval depends on the nature of the work, not on whether it needs planning permission. A project can be permitted development for planning purposes while still requiring full Building Regulations approval, and conversely a project might need planning permission while being exempt from Building Regulations for some technical aspects.

For most significant building works, both apply. An extension that is within permitted development limits still requires Building Regulations approval for its structural design, thermal insulation, fire safety provisions, drainage connections, and other technical aspects. A loft conversion within permitted development still requires Building Regulations approval for the structural work, thermal performance, escape window provisions, fire protection, and staircase.

Works That Are Permitted Development and Still Need Building Control

Common examples where both permitted development and Building Regulations apply include rear single-storey extensions under four metres deep on a detached house, loft conversions that do not exceed 40 or 50 cubic metres depending on house type, garage conversions to habitable use, and replacement windows and doors. For extensions, a Building Regulations application covering the structural calculations, thermal performance, drainage, and other relevant parts is required before or during the work. For windows, installation by a FENSA-registered contractor provides self-certification as an alternative to a formal Building Control application.

Lawful Development Certificates

For permitted development works, it is possible to apply to the local planning authority for a Lawful Development Certificate, which formally confirms that the proposed works are lawful under permitted development rights. This is not a planning permission but rather a certificate of lawfulness. It is separate from, and does not substitute for, Building Regulations approval.

Summary

Permitted development rights and Building Regulations approval are entirely separate requirements governed by different legislation. Having permitted development rights does not exempt you from Building Regulations. Most significant building works, including extensions, loft conversions, and garage conversions, require Building Regulations approval regardless of their planning status. Always check both requirements before starting work.