FRAMING FOR HEAVY ROOFING-TILE. There are some special features that should be noted in regard to the proper framing of a tile roof and its preparation to receive roofing tile. Rafters should be at least 2 inches by 6 inches, and 24 inches on centers, or closer according to length of span. Sheathing should be securely nailed, and should be either of common lumber laid tight and well joined together, or of matched and dressed sheathing securely fast ened. The roof pitch may be as low as one fourth (provided slope is not of extreme length), and from that to the vertical.
Before the tile are laid, the entire roof should be carefully covered with one layer of good roof ing felt, laid to lap two inches in every course, and to be turned up against the sides of the building at least four inches. If the building has a box or cornice gutter, felt should lap over top of metal at least four inches, and the same at valleys. After felt is so laid, same should be stripped with good white pine plastering lath, laid parallel, true, and straight, to facing board at eaves. The top edge of first line of lath should be 12 inches above the lower edge of facing board or starting strip; and thereafter not less than 12 inches nor more than inches space allowed from the top edge of each line of lath to the top edge of the next above and parallel. The tile hook over these strips;
and each tile is fastened with a seven-penny galvanized or copper wire nail.
All ridge-boards should extend three inches above top of sheathing, and hip boards two and one-half inches, and both be of seven-eighths inch common lumber. Facing board or starting strips at eaves under bottom end of tile will extend up above the top edge of sheathing one and five-eighths inches. In all cases facing boards at gable ends should be flush with the sheathing.
In some cases an open roof construction is used—that is, one with no sheathing under the tile. In that case, there must be a space of twelve inches between the lower edge of the lowest purlin to top edge of the purlin next above it, and thereafter a space of not less than twelve inches nor more than twelve and one fourth inches between the top edge of each purlin to the top edge of the purlin next above it. These purlin strips should be inch by 2 inches or over, the bottom strip 11/4 inches higher than the strip next above it—that is, 2% inches by inch. In this construction the hip and ridge strips should be the same as if the building were sheathed.