Roof coverings Part 02 - Tile roofing

Tile roofing

Roof tiles are manufactured from clay and concrete to a wide range of colours and profiles suitable for pitches from 17 to 45 degrees. Greater pitches up to vertical cladding are achievable but require additional or special fixing. Roof tiles are generally sold by the thousand in crates or strap banded to be stored on site pallets.

Clay plain roof tiles

British Standard BS 402 provides for tiles of nominal or work size 265 x 165 mm. Table 1 of the Standard gives maximum and minimum deviations for manufacturing size. Also detailed are requirements for tile manufacture, colour, nibs, thickness etc. Where tiles 280 x 175 mm are required fora project, but otherwise comply with BS 402, then such a requirement should be stated when ordering. BS 402 recognizes that plain tiles of different specification are manufactured, and although the Standard is not intended to provide for such tiles it does not rule out their use. 

Plain tiles are laid using the double lap principle; this ensures that there will be at least two thicknesses of tile covering any part of the roof.I 

Concrete roofing tiles 

In accordance with the requirements of BS 473,550, concrete roofing tiles or concrete rolling slates are manufactured to be fixed either double lap or single lap. Single-lap tiles are fitted using interlocking principles; the lower edge of a tile is designed to fit closely to the upper edge of the tile adjacent. The overall work sizes and maximum and minimum deviations for manufacturing size are given in the Standard. The manufacture of tiles in sizes other than those stated in the Standard is not excluded, and such tiles may therefore be found in practice. 

Table 9.4 shows typical overall work sizes for single-lap concrete tiles, and an indication of labour outputs based on a squad of two tradesmen to one labourer. 

Concrete double-lap tiles have similar characteristics to those of clay plain tiles. The work sizes given in the Standard are 267 x 165 mm and 457 x 330mm, and maximum and minimum deviations for manufacturing site are again specified.