The short answer
Normally not. Swapping a mortar-bedded ridge for dry-fix on a house is a roof alteration that Class C of the permitted development rules usually covers, and the building's look stays the same. Check first if the house is listed, sits under an Article 4 direction, or has a planning condition about its roof. Flats are treated differently.
For most houses the answer is no. The exceptions are specific, and each one can be checked with the council before any work starts.
The general rule for a house
A planning application is only needed for development, and the Town and Country Planning Act 1990 draws that term quite tightly. Under section 55(2)(a), work that does not materially change the outward look of a building stays outside the definition altogether. A new ridge in tiles that match the old ones usually passes that test.
What does Class C allow on a house?
Class C in Part 1 of the General Permitted Development Order permits any further alteration to a dwellinghouse roof. Re-roofing falls under that heading, which is why a new ridge or covering on a house rarely needs an application. One limit applies to the work: it must not stand more than 0.15 metres proud of the original roof plane. A dry ridge replaces a ridge that was already there, and its tiles rise from the apex as any ridge does, so the point seldom arises in practice.
Building Regulations are a separate matter. If the finished covering weighs 15 per cent or more above what it replaces, the extra load has to be checked by a structural engineer or building control, and Building Regulations approval is required. That applies even where no planning permission is involved, and it is worth raising with your supplier before you order a heavier tile.
When the answer changes
Four situations call for a closer look before anyone starts. The first is a flat or maisonette. The permitted development rights in Part 1 attach to a dwellinghouse, and the order says that word excludes a building made up of flats, and a flat inside one. The second is a house whose original planning permission carried a condition removing those rights, which can happen on newer estates. The third is an Article 4 direction. The fourth is a listed building.
Does an Article 4 direction stop a dry ridge?
It can, but that turns on what the direction covers. Somerset Council's list of Article 4 directions lists a direction for the Staplegrove Road area of Taunton, plus several for villages around the town. The wording of each direction is the thing to read, so ask the council's planning team what yours takes away before any work begins on a house inside its boundary.
A conservation area on its own does not remove Class C. It does raise the importance of how a roof reads from the public road, and the council expects care over tile and colour.
Listed buildings and protected places
A listed house still has the permitted development in Classes B and C, since neither one carves out listed buildings. Listing then adds a second, separate control. Section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990 bars alterations that harm the character the listing protects, unless they are authorised, and that authority is listed building consent. A ridge change can alter the character of a listed home even when no planning application is needed, so the consent question comes first.
Who decides inside a National Park or a National Landscape?
Within Exmoor National Park, Exmoor National Park Authority acts as the sole local planning authority, not Somerset Council. In the Quantock Hills, Blackdown Hills and Mendip Hills National Landscapes, Class C stays in force, though dormers lose permitted development status. For a dry ridge the practical difference is who answers your question: the Park Authority inside Exmoor, and Somerset Council elsewhere in the county.
Our page on dry ridge in a conservation area goes into the look of the work, and our survey photographs the ridge as it stands before any price is given.
Planning and the law on dry ridge
The two questions are often mixed up. Planning permission is about whether the council has to approve a change. Whether a dry ridge is required by law is a different question, and the answer is no: Marley states that installing to BS 5534 is not required by law. What the standard sets out is good practice, and its 2014 revision made clear that bedding mortar cannot be trusted to hold ridge and hip units on its own.
What should I check before a ridge job starts?
Take four questions in order. Is the property a house rather than a flat? Is it listed? Does an Article 4 direction or a planning condition apply to it? Does it stand inside a National Park? If every answer is no, the work almost certainly sits within permitted development. If any answer is yes, ask the planning team before the job. Inside Exmoor that means the Park Authority.
The written price follows our survey. Our page on whether dry ridge is a legal requirement covers the standards side, and dry ridge and verge sets out the whole system.
More on planning and ridges
Can the council ask me to undo a ridge change I made?
If the work was permitted development, there is nothing to undo. If it needed consent that was not obtained, particularly on a listed building, the council can take enforcement action. Asking Somerset Council's planning team before the work starts is far easier than sorting it out afterwards.
Does a new-build house keep its permitted development rights?
Not always. Some planning permissions carry a condition removing permitted development rights, and the council's online planning record for the address shows whether yours does. If there is such a condition, a ridge change may need an application before work begins, so look it up early.
The full picture: Dry ridge and verge repairs in Taunton ยท More short answers