With the use of modern wind testing, plain tiles can perform just as well below the original specified roof pitch of 35°, in fact the tests proved as low as 25°. The majority of most people prefer to look at plain tiles at steeper roof pitches because of the aesthetic design they create. Roof pitches that are at a very low degree tend to look odd compared to the majority of roof pitches that we are accustomed to.
Single lap tiles with side interlocks are an advance on plain tiles. They can reduce the load on the roof and can increase the process of roofing. They are designed with side channels to drain water away, therefore only needs to be a single lay of tiles.
Plain tiles still maintain versatility as they can be laid on a curved roof. Bonnet hips and valley tiles are perfect fittings for the plain tiling process too. Roofers have a tendency to bed bonnet hip tiles on a full bed of mortar. The mortar is then struck flush with the outer edge of each bonnet. The process of spotting the bonnet on a smaller bed of mortar, which will be unseen, is more aesthetically pleasing to the eye.
Single lap tiles are designed with side channels to drain water away therefore a single lay of tiles is only necessary. Whereas slates and plain tiles need a double lay of tiling because water will pass through the side laps and is drained away by the slate or tile underneath. This is known as double lap tiling.
Traditional plain tiles are curved from tail to top. This design originates from clay tiles when it was easier to fire them with a curve instead of trying to produce the tile completely flat. Tiles designed with a camber across the width will make it easier to adjust a tile to sit flat on the tile below. There is a distinct shadow line with this tile which people find more attractive to see on their roof.
Machine made tiles comply with the geometric requirements of The European Standard EN 1304, therefore can be laid on roof pitches to a minimum of 35°. The British Standard for tiling and slating BS 5534 will only advise a minimum roof pitch of 40° for handmade clay plain tiles. This is because they do not comply with the more technical geometric requirements of EN 1304.
If you are considering a roof replacement project to your premises and need assistance please contact us on 02890 692 444.