Maintenance
While its crucial role is as the ‘hat’ of a home, a roof’s aesthetics are also important, so retain the shape and patina of old tiles and slates where possible
Acting as a barrier against the elements, a good roof will shed rainwater quickly and efficiently. If it fails, though, moisture will find its way into the fabric of the building below. Left unchecked, this will cause untold damage, which is why maintenance is vital and warning signs – such as water staining to internal surfaces and tile or slate debris on the ground – should never be overlooked.
Along with a roof’s practical role, its texture, colour and shape are important in defining the look of a house, so think carefully before making changes. Avoid quick fixes, such as applying spray foam to the underside, as this can trap moisture, is impossible to remove and will leave slates or tiles unfit for reuse.
Roofing is a skilled job and it is essential to employ a contractor who understands old buildings and the materials involved. Get several quotes for the work, and check that scaffolding is included and will be erected by a qualified scaffolding company. The National Heritage Roofing Contractors Register is a useful starting point.
How to repair
‘Among the most common problems with roofs on old buildings are broken tiles and nail fatigue (nails corroding),’ says Paul Wardle of contractor John Williams & Company. ‘Slipped tiles or slates are often an indication that a roof needs repair or maintenance.’ Other problems can result from rotten battens, poor flashing details at abutments, and mortar that has failed.
‘Once the roof covering starts to become dislodged and damaged, problems can quickly escalate,’ warns Nigel Dyer of tile manufacturer Keymer. ‘Sometimes, it is not just a simple thing like replacing a couple of tiles or slates: it is damage to the timber structure and moisture getting through to the surfaces underneath – a much bigger problem.’
Clay tiles may crumble due to frost damage but this does not mean that the whole roof covering needs replacing, notes Hayley Gibson of Messenger Construction of Collyweston. ‘Isolated repairs can often cure the problem. However, it is quite possible that the roof is lacking any underfelt and therefore it may be time to consider a full refurbishment,’ she explains.
Where wind or storm damage has resulted in tiles or slates slipping, they can usually be fixed back into place. ‘Where large areas of slates are slipping, this can be due to nail fatigue and it may be possible to refit them with straps known as tingles,’ says Paul. Rotten roofing battens or timber pegs can also cause problems and complete renewal is likely to be necessary.
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