Preparations of the roof for the laying of tile should follow similar lines described for slate roofs. Over the roofing-boards should be tacked asphalt roofing felt, weighing not less than 30 pounds per 100 square feet and lapping 2 1/2 inches.
The valleys should be lined with this felt, running the entire length, and then the flashing metal placed on top, secured with clips at intervals. The width of the valley metal should not be less than 24 inches, and both edges should be turned up 1/4 inch the entire length of the strip. The felt covering the main surface of the roof should lap over the valley metal 4 inches.
Cant strips must be nailed along the eaves to start the first course of tile, unless special tiles are provided. Copper nails should be used to fasten these tiles, and each unit should be locked with the next, as the pattern demands.
Tiles which border the hips should be cut close against the . hip board, and elastic cement used to make the joint tight. All hips and ridges are finished with specially designed ridge and hip roll tiles, and the interior spaces should be left empty and not be filled with pointing mortar as is sometimes done.