clay tool roof

Clay Tile Roofs

Clay tile is a durable, attractive roofing material. In the Southwestern United States and throughout Florida, round-topped clay tiles (called Mission Style and Spanish Style) are popular. Clay tile can also be manufactured with a flat top to approximate French and English aesthetics. Tile that looks like slate roofing and hand-split wood shake roofing is also available. Clay roof tiles come in many colors and finishes, offering consumers a wide range of looks and stylistic options. Clay is a high-end roofing material and usually installs for anywhere between $200-$500 per square, or 10’x10′ area of roof. Top of the line clay tile roofs sometimes cost as much as $1000 per square.

Although it is typically associated with warmer climates, certain clay tiles can successfully be used to roof homes and buildings in cooler climates as well. In cold areas it is imperative to select a clay roof tile with a low porosity, meaning one that doesn’t absorb much water. Selecting a low porosity clay tile decreases the likelihood of the clay tile roof being damaged by the freeze/thaw cycle.

Clay roof tiles are made by molding clay into a tile and baking it. Baking time and temperature can be manipulated to alter clay tile density. Surface treatments and various glazing processes are used to produce the wide selection of clay tile roofing materials. Variations to the profile and shape of the tile further increase the range of looks a clay tile roofing system can create.

The heaviness of clay roof tiles must be carefully considered as these roofing tiles are much heavier than other roof systems. A roofing contractor can advise you on the ability of your roof structure to support the weight of a tile roof. In some cases structural modifications may be required to ensure the safe installation and proper functioning of a clay tile roof system.

When correctly installed, clay tile roof systems are highly resistant to fire and leaks and typically last between 60-80 years.

Installation requirements for clay tile roofing

Roof Deck: According to the NRCA clay roof tiles should be applied over continuous wood decking. Plywood decking should be a minimum of 5/8 thick nominal exterior-grade plywood. For tile that has head lugs, batten and counter-batten systems may Be used. Battens need to be fastened to the roof deck with galvanized, corrosion-resistant, 8d common nails at approximately 12” on center. The NRCA recommends using caution when installing a new roof onto a roof deck made of OSB, preservative-treated wood, and wood treated with a fire-retardant coating.

Underlayment: The underlayment provides temporary waterproofing during roof installation and acts as a permanent secondary waterproofing layer to the outermost roofing material. Clay roofing tiles are a long-lasting product and require an underlayment with a comparable service life. The NRCA recommendations for underlayment, commonly called “felt paper” specify a minimum of one layer of No. 30 asphalt-saturated felt applied horizontally in shingle fashion on roof decks having a slope of 40 degrees or more. A minimum of two layers of No. 30 asphalt-saturated felt paper is recommended for roof decks with a slope between 18 and 40 degrees. The NRCA advises against installing clay tile roofing on roofs with a slope less than 18 degrees. For extremely cold climates the installation of an ice-dam membrane may be required. Check with a qualified roofing contractor for information about this additional underlayment.

Fasteners & Securements: Roofing nails used to install clay tile roofs should be 11-gauge or 12-gauge. They should be made of galvanized steel or an equally corrosion-resistant material. The nails used to install clay tile roofs should be long enough to fully penetrate all layers of roofing materials and reach into the underside of the roof deck. Nail heads should be smooth and flat with a low profile and shanks should be barbed for increased pull-out strength. Other methods of securement may be required depending on climatic and seismic factors, roof slope, local practices and building codes, and manufacturer recommendations. A professional roofing contractor will provide information as to the correct method of securement for the clay tile roofing you select. Alternative securement and fastening methods include wire tie and strapping systems, clips, lug-hung-tile and bedding tiles.

Flashing: When installing clay tile roof systems flashings should be installed around the perimeter edge, at any penetrations, in open valleys, and along vertical surfaces.

The NRCA does not endorse any specific clay roofing tile or clay tile manufacturer however they do recommend selecting materials that meet the American Society of Testing and Materials (ASTM) standards established for clay roof tiles, Standard C1167. Check product packaging to ensure it complies with the Standard Specification for Clay Roof Tiles.

Clay roof tiles come with warranties against manufacturing defects. Your roofing contractor should provide you with detailed warranty information pertaining to the specific clay roof tiles you select, as well as warranties offered by the contractor to cover roof installation.