Tile Roofs & Installation
Tile roofs are proof that all roofs are not installed the same. Clay tile roofs should last a minimum of 50 years before needing to be replaced, however here in the States some tile roofs need to be replaced after just ten to fifteen! This is primarily due to differences in American and European roof structure designs.
Until the 1980s, the vast majority of roofs in Europe had an open attic without any kind of underlayment between the roof and the supporting frame. This allowed for maximum airflow around the tile and kept condensation from forming underneath the tile. However, because of a sudden increase in building costs, Europeans began to finish attics much like in America to increase living space without much cost.
Within a couple of years however, the tiles roofs began to degrade and fail. After researching the matter, it was discovered that by finishing the attic, there was no more ventilation under the tile. This caused water to condense under the tile that would then freeze during the winter. Frozen water expands and this in turn caused the tile to flake and become brittle.
To combat this problem, Europeans began using visqueen (a prominent insulation/underlayment) combined with elevated battens. This allowed for the needed ventilation, but also caused a new problem. The water was now condensing under the visqueen and causing leaks. For this they created a visqueen with micro penetrations that would work well in allowing the condensation to evaporate until the penetrations clogged with dirt.
Finally, they developed a four by eight foot sheet made of low-density fiber cement. The water would absorb into the fiber and then harmlessly evaporate into the ventilation flowing under the tile. Further, should tile become damaged, the underlayment would keep water from penetrating the roof until repairs could be made. This system has worked flawlessly since.
Unfortunately, this system has not been fully accepted in America, and often tile roofs will lack proper ventilation, proper insulation/underlayment or both. When shopping for a tile roof, make sure that your prospective roofer uses a proper fiber underlayment and battens that run first vertically and then horizontally along the roof. Remember that a tile roof is not merely a statement of elegance; it is literally meant to last a lifetime and protect your home from water infiltration.