The short answer
Renewing a garage roof covering with something similar is not normally work that calls for a planning application. Raising the roof, changing its shape or working on a listed or protected building is where you should consult B&NES planning before ordering anything. Building Regulations is a separate question, answered by how much of the roof the job touches.
Planning and Building Regulations are different things
People often use the two terms as if they were one, and they are not. Planning permission concerns what a building looks like and how it sits among its neighbours. Building Regulations concern how it is made: structure, fire, weather resistance and energy use. A garage roof can raise one question, both or neither.
For a new covering much like the old one, laid on the same structure, the planning question is usually a quiet one. It gets louder when the work changes the building's appearance from outside. A roof that is higher, of a different shape or in a clearly different material is better discussed with the council before money is spent.
Please read this as general guidance, which is not legal advice. The rules depend on the property and its setting, so confirm with the planning authority for your address before you commit. The Planning Portal also carries plain guidance on roofs and outbuildings.
Replacing like for like
When a garage roof is re-covered in a similar material at the same height and shape, most owners will meet no planning obstacle, though the setting still counts. Swapping tired felt for a new flat roof system, or old sheeting for fresh sheets in the same profile and colour, is renewal rather than redesign.
What counts as similar needs care. Going from cement sheet to a heavier tile covering alters both appearance and load. Moving from flat to pitched alters the height and the profile, and our note on flat to pitched garage roofs explains what that involves. Changes like these belong in the ask-first group, and a planning officer can usually say quickly which side of the line a design lands.
Matching the existing look also helps with neighbours and with any restrictive covenants on the property. Some estates and title deeds limit alterations regardless of planning rules, so check your documents if a management company looks after your road.
Raising or reshaping the roof
Any scheme that makes the roof taller, adds a pitch, creates a dormer or rooflight, or turns the garage into living space enters more complicated territory. Planners look at height and bulk, at how near the garage stands to a boundary, and at what it does to a neighbour's light and outlook.
We do not set out permitted development limits here, because the detail turns on the building and its location, and a figure quoted for someone else's plot may not suit yours. The surest route is to describe the proposal to B&NES planning, or start with Planning Portal guidance, and then ask for the answer in writing.
If the plan includes a roof window, the rules are covered on our skylights pages and we point you there rather than restate them. Our guide to a garage roof overlay covers the case where new sheets go over old ones, which has its own effect on height.
Listed buildings, conservation areas and World Heritage
Setting can change the answer. If the garage is itself listed, or is attached to a listed house in a way that brings it under the same listing, consent for roof work comes from B&NES Council as listed building consent, which runs on its own track alongside planning permission. B&NES tells owners to contact the conservation team early, because carrying out works without consent may end in enforcement action. A garage with any listing connection is therefore a reason to phone before a single sheet comes off.
The city of Bath carries World Heritage status throughout, and the conservation area spreads over about half of its area. Certain streets are subject to Article 4 directions, which remove some everyday freedoms to alter a property. The council's list of examples runs from porches and sheds to painting, with roofs absent from it, yet your own street's entry on the policy map is the thing to look up.
Outside Bath, neighbouring councils apply their own conservation areas and rules. A garage in Chippenham, Frome or Bristol answers to a different council, and each publishes its own guidance online, so go to whichever authority covers your address. Wiltshire, Somerset, Bristol and the councils on the northern and western edges of our area all have separate pages.
Building Regulations for the roof itself
The Planning Portal says approval is not normally required for a re-cover that affects less than 25 per cent of the building envelope and less than 50 per cent of the roof. On a small garage, renewing the entire roof will usually exceed that half, so the question has to be asked, not assumed. If approval does apply, the roof's insulation could need improving to current thermal performance as part of the same project.
Approval is also triggered if the new covering is 15 per cent or more heavier than the old, with a structural check to follow. That matters when light sheeting is replaced with concrete tile, because the walls and wall plates were designed for far less load.
Approval comes through B&NES Building Control or a registered building control approver, and on notifiable jobs we take care of the paperwork. Timing is a separate matter: our page on whether a garage roof can be replaced in winter deals with scheduling, and the insurance side of a failed roof is under garage roof insurance. The overall job is described under garage roof replacement.
