What Points Need to Consider With Terracotta Clay Tile Roofing?
Posted By Becky on March 19, 2015
Today, the building – a city block’s worth of granite, exquisitely used terra cotta for decoration, and bronze windows – does not look much the worse for wear. Its roof is covered with one of the oldest and most durable building materials – Terracotta clay tiles.
Of course, such a timeframe far exceeds what reasonable designers will promise, but many institutions still expect their buildings to last for generations. Terracotta Clay tile are frequently used on monumental buildings and usually can last 75 years or more. On the downside, such roofs represent a significant initial investment that can be quickly destroyed by faulty design, workmanship, or materials. Here are some key requirements for long-lasting terracotta clay tiles.
1.Material. Not all clay tiles are created equal, and we do much research on many roofs that were ruined by frost damage shortly after installation. As a general rule, the tiles must have a successful performance track record in the climate where they will be installed. Except to reviewing actual performance, prudent designers will gauge material performance with laboratory tests.
2.Gutters and flashing. The notion that all materials combined in one assembly should have the same life expectancy is an elementary principle of building design. Clay tile roofs include important perimeter flashing components that must be constructed from durable, stainless steel or heavy-gauge copper instead of aluminum or galvanized sheet metal.
3.Underlayment. Terracotta clay roof tiles are “water-shedding systems.” It means that some water is expected to find its way under the tiles (windblown rain, for example) and must be intercepted on a waterproofing membrane. The most reliable assemblies will have a layer of self-adhered waterproofing membrane, which sticks to the roof deck and prevents leakage when water backs up behind ice dams and at the same time seals around roof fasteners. One important caveat: Self-adhered membranes can invite condensation in some buildings and climates.
4.Attachment. Terracotta clay tiles must be attached to the roof deck to prevent wind uplift and avoid “chatter” (the noise generated when tiles rattle against each other in gusty wind). Look for nose clips that restrain the front edge of the tiles; along roof perimeters, look for corrosion-resistant copper or stainless-steel nails. Avoid foam adhesives that are sometimes used to attach clay tiles and provide much less reliable attachment.
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