Does replacing ridge tiles need Building Regulations approval?

Building Regulations reach roof work, though not every roof job needs an application. The Planning Portal sets two limits for a replacement covering. The work must touch under 25 per cent of the total building envelope, and under 50 per cent of the roof itself. The envelope counts everything that wraps the house, from the walls and floor up to the roof, its windows and its rooflights. Keep inside both figures and no building control application is normally required.

A ridge is a single line of capping at the apex. Rebedding it, swapping a few cracked pieces or refixing the whole run uses a sliver of the roof area and a smaller sliver again of the envelope, which is why a ridge job on its own sits far below the limits. The test belongs to the building, though, not to one trade's estimate of its own part. If the ridge is repaired in the same visit as a patch of slopes or a lead job, the sum is taken over all of it.

Arun District Council includes new coverings for sloping and flat roofs in the alterations it expects people to bring to building control. Set beside the Planning Portal's limits, that can look like two answers to one question. They fit together if you read the council's line as an invitation to ask, not a ruling that a ridge repair is notifiable: re-roofing often needs approval, and the council's team can say whether a particular job does.

The quickest route is to put the question to the building control team before any work begins. If your house is in Chichester, Worthing, Havant or another district, that council has its own team, and a private registered building control approver is another route. Private building control is older than the registration regime that began in April 2024. Where a job is notifiable, we set out what is required and send the notification to the building control body ourselves.

Four triggers matter. Going over the percentage limits is the first. A structural alteration is the second. The third is a new covering whose reaction to fire differs markedly from the old. The fourth is a covering that adds weight: the Planning Portal sets the trigger at an increase of 15 per cent or more, while Approved Document A speaks of loading raised by more than 15 per cent. Both wordings lead to a building control conversation and, often, a structural check.

Capping tiles weigh little beside the slopes below them, so swapping like for like rarely reaches any of the triggers. The position changes when the ridge forms part of a larger re-roof, or when a heavier tile and a new ridge system go on together. Then the whole project is measured, and thermal upgrade rules under Part L can apply as well. We say which side of the line a job falls on when the survey is done, before the written quote is issued.

Planning and building control are separate regimes. Under the Town and Country Planning Act, if an alteration leaves a building's outward look essentially as it was, the Act does not treat it as development, so matching ridge tiles on an ordinary house will not usually call for planning permission. Two caveats apply: a listed building, and an Article 4 direction that withdraws rights from a defined area.

Anything that changes a listed building's character needs listed building consent. According to the South Downs National Park Authority, regular maintenance is outside it, as are minor repairs that match what was there before. Changing a bedded ridge to a dry-fixed one alters the look of the top of the roof, so raise that with the conservation officer before you commit. In a conservation area, ask the council whether a direction affects your street. Inside the National Park, applications go to the Authority or, in some districts, to the district council acting for it.

Alongside the regulations sits BS 5534, the slating and tiling standard. Its 2014 revision moved ridge and hip tiles away from reliance on mortar, so they now carry a mechanical fixing too, and dry-fixed systems are tested to BS 8612. Marley points out that installing to BS 5534 is not itself a legal requirement. It is nevertheless the benchmark a careful contractor follows and one a surveyor or building control officer will recognise.

It is how we work on every ridge: each tile is held mechanically, whether the roof gets a bed or a clip system. Where an old roof carries reclaimed tiles, the standard itself allows that parts of it may be ill-fitting, so the repair is matched to what is there. For the fixing detail, see our guide to BS 5534 for ridge tiles, and for the work itself the ridge tile repairs page.