Concrete roof tiles are about three times as heavy as traditional asphalt tiles, but most houses can support their weight without any problems. Concrete roof tiles have some advantages over asphalt: They are incredibly sturdy and hold up better under extreme weather conditions; they can also be walked on without cracking, which makes it easy to put up Christmas lights or do roof maintenance. With properly installed concrete roof tiles, your roof can hold strong for more than 50 years.
Cover the roof with roof underlayment. Use asphalt-saturated felt, which is the traditional roofing underlayment, or synthetic underlayment, which is more expensive but longer-lasting. If you live in a wet or snowy climate, use a self-adhering underlayment, which has an ice and water barrier. To apply underlayment, start at the bottom of the roof. Unroll 5 to 6 feet of underlayment, line it up with the edge of the roof and then nail it into place with a nail gun. Repeat the process until you reach the end of the roof. The next row of underlayment will overlap the first row by 2 inches. Lay the entire roof this way. When you reach the peak of the roof, leave it uncovered and work from the eave up on the other side of the roof. When you reach the peak, lay one piece of underlayment over the peak so that it overlaps the underlay on both sides. Nail the underlayment into place.
Attach the tiles. If the tiles do not have anchor hardware on the back, use the nail gun to nail them into place. If they do have anchors, use battens, which are simply pieces of wood that lay horizontally on the roof and are spaced at equal intervals. Cut enough 1-by-4 battens to place one 10 inches up from the eave on both sides and then one batten every 6 inches after that. Attach the battens to the roof with 3-inch roofing nails. Specific instructions for attaching the anchor to the batten will be included in your tile package; the anchor will either screw into your batten or lock onto it in some other way.
Begin laying your tiles at the eave with 2 inches overhanging the bottom of your roof. Concrete roofing tiles have a side-by-side locking system to prevent water from getting through. Instructions on how to lock them will be included with the tiles but is as simple as sliding the side of one tile into the side of another.
Overlap each row by 6 inches. If you have placed your battens at 6-inch intervals, your tiles will already be set up to overlap that way. To make your nonanchored tiles overlap by 6 inches, move up the roof and make chalk lines every 6 inches. Line the top of your tiles up with these lines.
Top your roof with a metal ridge cap. Metal ridge caps can be purchased in sections or you can bend some yourself if you have extra sheet metal. The ridge cap should fit snugly against the roof and overlap the tiles below by at least 4 inches. Attach the ridge cap with a drill and 3-inch screws. Caulk between ridge cap pieces where they overlap to create a waterproof barrier.
Check the weather and make sure that you will have a few dry days following installation. The tiles take two days to dry completely.