Asphalt Shingle Roofing near you

The honest comparison starts with what is already on the building. British coverings are heavy, brittle and long-lived, and the timber under them was sized for that weight. A shingle covering is light by comparison, and lightness is not automatically an improvement. Approved Document A's test for re-covering runs in one direction: a significant change in roof loading is when the loading upon the roof is increased by more than 15 per cent, and where the applied loading changes significantly the structural integrity of the roof and its supporting structure should be checked so that the finished building is not less compliant than before.

Going lighter moves the problem to wind. The Planning Portal's guidance on roof loading lists the loads a roof carries as the materials, the weather in the form of wind, snow and rain, and maintenance access by a person, and says the roof should be tied down to the structure to stop it lifting in strong winds, normally by straps roughly 1.2 metres long with a cranked end fixed to the wall plate and the inner skin of the wall at 2 metre centres. A covering that weighs a fraction of what the original weighed has to be held down by its fixings instead of by its own mass.

Fire is the second difference and it bites hardest on outbuildings close to a boundary. Approved Document B devotes a section to resisting fire spread over roof coverings and sets separation distances by the type of roof covering and the size and use of the building, measured to the relevant boundary. A garage or garden room a metre from next door's fence is exactly the case where the covering specification is decided by that table rather than by preference, and the Planning Portal names a covering whose fire performance would be significantly different from the existing one as a trigger for building control approval in its own right.

Re-covering a roof is controlled work rather than decoration. GOV.UK's list of alteration projects needing building regulations approval includes replacing roof coverings on pitched and flat roofs, and there are two lawful routes to satisfy it: apply to a building control body, which is either your local authority's building control department or a private registered building control approver, or use someone registered with a competent person scheme, in which case you do not need to get approval yourself. GOV.UK's published scheme list is specific for this work, naming NAPIT and CompetentRoofer, the latter operated by the National Federation of Roofing Contractors Limited, as the authorised schemes for replacement of roof coverings on pitched and flat roofs including any necessary connected work but not solar panel installation.

Two of the triggers land squarely on a change to shingles. The Planning Portal's guidance on work to an existing roof says approval is needed where the performance of any new covering will be significantly different to that of the existing covering in the event of a fire, and where a new covering material increases the weight of the roof covering by 15 per cent or more. It also gives the threshold below which a building control application is not normally needed for repairs or re-covering: less than 25 per cent of the total building envelope affected and less than 50 per cent of the roof affected.

Planning permission is usually a separate and easier question. The Planning Portal's position is that work to the roof of a house that does not materially affect its external appearance will usually not require planning permission, but a shingle covering replacing slate on a visible elevation is precisely the sort of change that can materially affect appearance. In a conservation area, or where an Article 4 direction has removed permitted development rights, ask the local planning authority first. On a listed building, national planning practice guidance is blunt: any works to alter it in a way that affects its character as a building of special architectural or historic interest require listed building consent, there is no fee for applying, and doing the works without consent is a criminal offence under section 9 of the Planning (Listed Buildings and Conservation Areas) Act 1990.

The deck decides the job. Shingles are a continuously supported covering, so the boarding or sheet material beneath them has to be sound, flat, dry and adequately fixed before anything bituminous is laid. On a garden building this often means checking the manufacturer's kit rather than assuming, and on an old garage it usually means stripping the previous felt back to see what the boards are actually like after years of a leaking covering above them.

Above the deck comes an underlay, then the shingles themselves in overlapping courses from the eaves upwards, with the eaves, verges, abutments and any penetration each detailed separately. Approved Document C's requirement for dry joints is that they should be designed so precipitation will not pass through them, or the system designed so that water entering the joints is drained away without penetrating beyond the back of the roofing system, and it adds that whether a dry joint is suitable depends on the design of the joint and the severity of the exposure to wind and rain. On an exposed or coastal site that sentence is the whole argument for a better detail at the edges.

Fixing is where a shingle roof is won or lost. Approved Document C asks that each sheet, tile and section of roof is fixed in an appropriate manner and points to the British Standard on workmanship for slating and tiling. For shingles this means the specified nail pattern, the specified nail, and the sealing strip bonding properly to the course below, because a shingle that has not bonded is simply a flap waiting for a named storm. Pitch matters too, and the minimum pitch is a manufacturer's figure for the particular product rather than a single national number, so ask which product is being used and what pitch it is approved down to.

A shingle roof in Britain rarely fails in the middle of the slope. It fails at the edges, in the joints and at the penetrations, which is why the specification of the eaves, verges, abutments and flue or vent details tells you more about the life of the covering than the headline product name does. Exposure is the other half: a sheltered inland garden room behind a hedge and an exposed coastal workshop taking salt-laden driving rain are not the same job, and Approved Document C explicitly ties the suitability of a dry joint to the severity of the exposure to wind and rain.

Ventilation of the space below matters as much as the covering above. A warm, humid garden office with a sealed, unventilated deck will rot from the inside while the shingles still look new from the ground. Approved Document C covers roofs in three parts for exactly this reason: resistance to precipitation from outside, the risk of interstitial condensation within the construction, and the risk of condensation or mould growth on the internal surface. Ask any contractor quoting for a shingle roof over a heated or occupied space how the construction deals with the second and third of those, not only the first.

Ask for the covering to be named on the quotation: the product, the pitch it is approved down to, the underlay, the fixing pattern and how the eaves, verges and abutments are being detailed. A shingle quotation that says only the words felt shingles has left every one of those decisions to whoever turns up on the day.

Where the work is notifiable, keep whatever the route produces. GOV.UK's warning is plain: without approval you will not have the certificates of compliance you may need when you want to sell your home, and the person doing the work could be prosecuted and fined if the work does not comply. If a competent person scheme member does the job, the scheme certificate is the evidence, so file it with the deeds rather than in a drawer.