If you live in an area with cold weather conditions, or strong freeze/thaw tendencies, do your research before purchasing concrete roofing tiles.
"We've seen significant failure due to freeze/thaw with concrete products at our elevation of 6,000+ feet," says Trevor Cannon with Umbrella Roofing, Inc. in Colorado. "Some high end concrete products experience this problem less, but those products are very expensive."
In really cold climates like northern Ontario, concrete roofs have never been a popular choice according to homeowner Barry George, who recently had a DaVinci Roofscapes synthetic slate tile installed on his home. "In all honesty, I've never seen concrete tile used in these parts," says George.
Why don't cold weather conditions and concrete mix? First of all, concrete tiles are heavy (weighing up to 1,100 pounds per square depending on the style). Second, those heavy tiles have a high water absorption rate of about 13%. Water (or ice or snow) absorbed into the already heavy tiles puts pressure on the roof structure and can result in cracking of the tiles.
Just imagine a crisp winter day in Chicago ... or Colorado ... or upstate New York. Now think of an installed concrete roof with melting snow being absorbed into the tiles. Nighttime comes and the moisture stays in the concrete and freezes. This makes the concrete potentially more brittle and heavier on the roof structure. And, the trapped moisture can form mildew over time.
If you live in a cold climate and you're considering concrete roofing, do your homework. See Cold Weather? Bring on the DaVinci Roofing Tiles! and Things to Think About for Cold Weather and your Roof.