How the tiles are laid

Planning

Contractors who start early and plan late tend to regret it, and by then it is too late to change. Settle the area estimation, the number of tiles, the batten spacing, the count of ridges and accessories, and the weather forecast before anything goes up.

• Area estimation
• Number of tiles to purchase
• Batten spacing (gauging)
• Ridges and other accessories
• Weather forecast

Framework

In Kerala and Tamil Nadu there are broadly two roofs: a sloped concrete roof, where purlins are simply affixed to the existing slope, and a flat roof, where a steel or wooden truss has to create the slope first. Purlins run horizontally to give the tiles a stable platform; rafters run vertically and carry most of the load. Both are sized to the span of the room.

Placing the tiles

With the purlins spaced accurately, tiles are laid from the bottom upwards, the batten lug on each tile stopping it from sliding down the slope. You can walk on them while you work. Concrete takes the weight. Sirex tiles do not need nailing to the purlin; the interlock and the weight hold them.

Ridges and accessories

Ridge tiles, apexes and barge tiles are bedded with cement mortar at the junctions and edges. Roof clips are used where extra stability is wanted. This is the stage that decides whether a roof looks finished or merely covered.