Planning permission and building-regulations approval are separate checks. A change that is permitted development can still need technical approval. Start with GOV.UK building regulations and check the exact scope with your local authority.
In England and Wales, party-wall guidance can apply to work on or near shared boundaries. A notice or agreement depends on the proposed work; it is not required for every internal refresh. Confirm the process before starting.
Choose the use first
A place for boxes, an occasional workspace and a new bedroom are different projects. Tell your designer the intended use before asking for a stair or floor layout. Do not assume that boarding an attic makes it suitable for living space.
Survey the roof and route into the room
Record the roof form, usable height, existing access and visible services. Ask a competent professional to check loading, structure, stair access, fire precautions, insulation and ventilation. A dormer, rooflight or roof change can bring additional planning considerations.
Check the property-specific permissions
Permitted development depends on the proposal and site. Listed status, conservation areas and Article 4 directions can change the process. Use your local planning authority to establish the requirements for the exact address. Ask who will submit applications and arrange inspections before agreeing a start date.
Check the England volume limit and every other condition
For a house in England, the roof-enlargement permitted-development allowance is up to 40 m³ for a terraced house or 50 m³ for other houses, counting previous roof additions as well. Those figures are only one condition: roof height and the principal slope facing a highway, materials, designated land and other restrictions also matter. Flats are not covered by this householder allowance. Confirm retained development rights, listed status and any Article 4 direction with the local planning authority. Use Planning Portal’s England loft-conversion checklist and GOV.UK householder technical guidance for the full conditions; volume alone does not establish permission.
This planning checklist covers England. Wales has a separate planning regime: check Welsh guidance for a Welsh property. The party-wall link above describes the separate England-and-Wales process. For a dormer or rooflight, have the actual proposal checked; a generic concept does not establish permitted development.
Write a comparable quote brief
Separate survey and professional fees, approvals, structure, stairs, insulation, services, surfaces and waste handling. Record what each contractor assumes about the roof and existing building. Compare alternatives such as a storage refresh and a habitable conversion as separate scopes.
Use a concept carefully
An image can help discuss light, storage and finishes. It cannot verify a structural design or establish compliance. Mark roof slopes, openings and services that must stay, then review the idea with your professional.
Return to the London attic planning range or attic cost guide once the scope is clear.
Official guidance checked 8 October 2026. Confirm the requirements for your address and proposed work before commissioning it.
Explore finishes using your own room photo. Keep real measurements, roof slopes, access and approvals in the brief.