How to Install Flat Clay Roof Tiles
Flat clay roof tiles are interlocking units that differ from the rounded U-shaped clay tiles that are known as Spanish or Mission style. An advantage of flat clay tiles is that they are easier to install than Mission style ones, making them a practical DIY home project. They can also be installed on flatter roofs with less steep pitches than these traditional U shaped tiles allow.
Step 1: Check Building Codes
Look up your local municipal building department and a local roofing supplier to make sure your roof's structure is sound enough to handle a flat clay tile installation. Flat clay tiles can be installed on roofs with a shallower pitch than other types of clay tiles. It is recommended to install them on a roof with a pitch of 4 by 12 or less. Pitch is determined by applying the mathematical slope rule of rise over run. Use a carpenter's tape measure to determine this, and make note of this calculation.
Step 2: Determine Underlayment
Read the tile instructions to determine whether your clay tiles will need underlayment material. Some flat clay roof tiles can be attached directly to the sheathing, and others need wood battens to be fastened down first. These are strips of redwood or pressure-treated pine that typically measure 1 by 2 feet. They are also available in 1 by 3 feet measurements if these are found to fit better with the area of your roof.
Also attach these wood battens along rakes, eaves, and rafters if you plan to extend the tiles over the side edge of the roof. Be sure to space them at intervals that will match up with the tile pattern. 14 to 16 inch intervals are the most common. If the clay tile instructions dictate, you may have to install larger battens along roof hips and ridges for additional support; these are typically 2 by 2 feet.
Step 3: Lay the Tile
Use copper flashing and nails if possible, since these are as durable as the tiles and will last a long time with few replacements. If you need to attach an underlayment, apply a metal drip edge along the roof eaves at the same time. Select flashing that is at least 2 feet wide, and attach each tile clip to the support battens on one end and to the underside of the tile on the other end.
Fit each tile against the others before nailing them down; if there is not at exact fit, trim the tile edges with your circular saw. Always wear your safety glasses when performing this step. Each flat clay tile should fit in the entire course without placing any stress on the adjoining tiles. If you live in an area with high winds or frequent storms, fasten your metal tile clips at every third or fourth course of wood battens. Make sure to still observe local building codes in this case.