Do you need planning permission to replace a garage roof?

Under section 55 of the Town and Country Planning Act 1990, a job that leaves a building's street appearance substantially as it was is not development at all. Stripping an old felt, tile or sheet covering and fitting a replacement of the same kind belongs in that category, so no application is needed in the ordinary case. Colour and texture still count, because a dark felt swapped for bright new metal sheet can stand out from the street.

Note the words materially and external appearance. Swapping grey felt for new grey felt is invisible from the street. Changing a flat roof to a pitched one, or replacing tiles with a very different cladding, changes how the building looks, and that is where the question of permission begins. If it helps to see the principles written out, our wider guide to planning permission for roof work covers them, and the garage roof pages under garage roof replacement take each question in turn.

If the garage is listed, or stands within the grounds of a listed house, the rules get stricter. Section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990 means you must have consent before altering a listed building in a way that touches its character. The South Downs National Park Authority tells owners that everyday upkeep, including small repairs using the same material in the same place, needs no listed building consent, but a change of covering is not upkeep, so ask first.

Whether a particular garage falls under a house's listing depends on its age, its position and how it relates to the house. That is a question for the council's conservation officer, not for a roofer or a neighbour. Do not start the work first and ask afterwards, because consent cannot be arranged once the roof has already changed.

A conservation area does not by itself stop a like-for-like roof renewal. An Article 4 direction is different. It lets a council switch off named permitted development rights inside a mapped area, and each direction lists exactly which rights go. Ask the council for a copy of any direction covering your road, and read the list of classes it removes, because some are narrow and cover only boundary walls or chimney work.

Around Bognor, Arun District Council's directions concern houses let to several households in the Marine and Hotham wards, and the fencing of verges and paving of front gardens at Craigweil House in Aldwick. Neither takes away a roof right. Directions elsewhere do bite on roofs: in Old Portsmouth's Article 4 area, replacing the roof cladding on a street-facing front is controlled. For a Chichester address, check with the district council directly. For a garage inside the South Downs National Park, our guide to South Downs roof planning explains which authority decides where you live.

Raising a roof, changing its shape or putting in a window is a different category from a like-for-like swap. Class C permitted development covers other alterations to a house roof. It restricts how far anything may project from the slope and caps the height at the original roof's highest point, and windows put into a side slope must have obscured glass. Those rules are written for a dwellinghouse, and flats are excluded, so a detached garage needs a check with the council rather than an assumption. Altering the pitch, adding a parapet or raising the walls beneath the roof all change the outline of the building, and the council is the body to say whether that matters.

If you have a roof window in mind, read our garage roof skylight answer. If the garage is becoming a room, the garage conversion roof page covers the extra rules, because a conversion usually brings both planning and building control questions.

For a Bognor Regis garage, ask Arun District Council's planning team. Elsewhere in our area, ask the council covering your district. In the South Downs National Park the answer depends on where you are, because the Park authority decides directly in some districts while the district council acts on its behalf in others.

We explain consent as part of the survey. Where the work looks as if it needs approval, we tell you before pricing it, so you are never surprised halfway through. A single written total comes after that. A short email to the council, with the address, a few photographs and a line on what you plan, usually earns a written reply that is worth keeping. Approval under the Building Regulations is a different process again, and our answer on garage roof building regs covers them.