Roof design is quite a complex field and involves many calculations regarding the strength of the materials used. A roof has to withstand very high wind speeds and snow loading and each roof is designed to carry the covering, usually tiles, that is put on it.
The coverings are fixed onto battens which are spaced out up the roof. Each batten is nailed to every rafter it passes over. Underneath the battens is a roofing felt or membrane. There are various makes of membrane but each one serves as both a vapour and a dust barrier. That is, it stops warm air from inside the roof space hitting the cold underside of the tiles which causes condensation. This roofing membrane is not a secondary waterproof layer for the roof.
Which roof covering should I consider?
- Natural Roof Slates are particularly suitable as a roof covering as they have an extremely low water absorption index of less than 0.4%. Its low tendency to absorb water also makes it very resistant to frost damage and breakage due to freezing.
- Clay Plain tiles are a very traditional British idiom. The format is tiny in comparison to others, usually 165 x 265, and the fact that the usual amount of each tile which is visible is just 100mm means that the coverage is 60 tiles/m². And plain clay tiles also have to be laid at traditional roof pitches, more than 35°. They look good on steeply pitched roofs and are particularly good on small roof sections, such as on dormer windows or porches where large format tiles would look out of place.
- Concrete interlocking tiles are much quicker to lay than traditional slates or plain tiles as they are generally of a larger format, typically 420 x 330mm and therefore need relatively few to cover a roof. The coverage rate is typically around 10 tiles/m². They can also be laid at very shallow pitches, some at as little as 14°.
- Interlocking Pantiles are often used in the Channel Islands and it is essentially an earlier form of an interlocking tile, as are the traditional Spanish and Mediterranean roof tiles which are sometimes used in Britain.
There is more to a roof than just slate or tiles. There are also the many accessories and finishings to consider as well as other options such as ventilation, metal roofing and solar panels.
Flat roofs are constructed basically with joists spanning the gap between two walls, covered by sheet timber or other material. In the case of timber a further, waterproof cover is required such as felt or fibreglass.
All our battens, membrane, felt, roof tiles, screws and nails are available to collect from our drive-through, shop and back yard in Rue des Pres Trading Estate, St Saviour, or delivered free of charge to any destination islandwide. Pop in, contact us or call us on 01534 888000 for more information.