Last Updated: Feb 18, 2021
The look of terracotta roofing tiles probably reminds you of a Greek villa overlooking the Mediterranean Sea or a beautiful Spanish-style hacienda keeping a homestead pleasantly cool during the hot and humid tropical summers. Terracotta ceramics and pottery have been in use in Greek pottery for around 9,000 years. As a building material, fired terracotta tiles are first linked to ancient Chinese builders around 10,000 BCE. This fact makes these tiles one of the oldest forms of vernacular construction known to humanity.
Clay or terracotta roof tiles are the perfect example of local building materials. For this reason, it has been the most popular roofing material in various civilizations throughout history. Clay soil is endemic to almost every region worldwide. As long as people had access to clay soil and organic material that could be burned, clay terracotta tiles provided a durable and waterproof roofing option that could be manufactured onsite. Today, terracotta roofing tiles continue to be a popular option for high-end homes looking for a beautiful and natural roofing material that can add value to the home.
Terracotta roofing tiles were traditionally made from locally sourced clay molded into a tile shape and fired in an oven or kiln. The firing process turned the clay into a slightly porous, though waterproof material used to protect homes from wind, rain, and other elements. Clay terracotta tiles are generally made in two different shapes: rounded pan-shaped tiles or flat tiles. Builders mostly used rounded tiles in areas with frequent rain. The rounded tiles were placed in an overlapping fashion to stop rainwater from leaking through the roof. Flat terracotta tiles were also overlapped, though they tended to be used more in drier areas.
Today, many companies that market terracotta tiles make these tiles from tinted concrete. Though these options may resemble terracotta tiles in appearance, they are not a natural building option. A large amount of cement in these roofing tiles significantly increases this alternative's embodied energy footprint. In this article, we define terracotta roofing as roofing tiles made only out of baked clay.
One of the defining aspects of terracotta roof tiles is the dark orange color from the baked clay. The kiln-fired process of making these tiles can lock in their color and long-lasting durability.
One of the most appreciated aspects of terracotta roof tiles is the unique aesthetic that it gives to the home. The natural clay color combines with almost every type of exterior cladding. It provides an unmistakable "Mediterranean villa" look to your home.
As with most aspects of natural and green building, the answer to this question is: "It depends." Suppose terracotta tiles are made from locally sourced clays and processed in energy-efficient kilns that limit energy expenditure, then yes. In that case, terracotta roofing is one of the most environmentally friendly roofing materials available. However, suppose those tiles include large amounts of cement aggregate or are shipped across the world. In that case, their environmental footprint will be significantly larger.
Terracotta roofs are one of the heavier roofing options. Limiting the distance they travel between the extraction, manufacturing, and building site will be a significant factor in maintaining this natural roofing alternative's environmental advantages. In comparison, both asphalt tile and metal roofing options have enormous embodied energy footprints due to the mining, manufacturing, and shipping processes involved.
Terracotta tiles are essentially made from one ingredient—clay that is fired in a kiln. These tiles do not require any aggregate, adhesive, or other chemical elements that could potentially off-gas into your home or in the surrounding environment. For homeowners looking to establish a rainwater catchment system, terracotta tiles won't leach any heavy metal or other potentially harmful elements into the water you catch and store in a cistern. However, they will require regular pressure-washing to remove debris from the roof that could clog the rainwater harvesting system.
Terracotta roof tiles are among the few hundred percent natural roofing options available to homeowners living in cold or temperate climates. One of the main benefits of this roofing option is creating a roof from one of the most abundant resources on earth—subsoil. As we mentioned above, good quality clay, or subsoil, can be found in virtually every region of the planet.
Unfortunately, the main drawback is that there are not many local terracotta roof manufacturers in North America. However, with a bit of research, you should be able to find a terracotta tile manufacturer within the general vicinity of your building site. For example, for homeowners in the Midwest, Ludowici makes high-quality terracotta tiles from locally-sourced raw materials in Ohio.
Another underappreciated benefit of terracotta roofing is that the thick clay layer can improve your home's energy-efficiency. Clay tiles can retain heat well and provide excellent thermal performance to reduce the energy needed to heat and cool your home. In under-insulated homes, upwards of 85 percent of heat loss occurs through the attic and roof. When combined with adequate attic insulation, a terracotta roof can help to reduce your monthly energy bills while minimizing your home's carbon footprint. Terracotta tiles are also a good option for houses in hot climates. The light color of the clay roof tiles can reflect the sun's heat, thus keeping homes cooler with less need for supplemental air conditioning.
Clay terracotta tiles are incredibly durable. When properly installed, they can easily last for 100 years or more. The only maintenance required is periodic cleaning with a pressure washer to remove any moss or other debris accumulated over time. Some clay tiles come sealed with a polyurethane coating to increase moisture resistance and avoid organic material buildup. Also, terracotta tiles are an excellent option for homes located in coastal areas where salty air can damage metal and asphalt shingle roofs. Their excessive weight can withstand hurricane-strength winds. The kiln-fired clay is practically immune to the constant battering of sea spray.
On the downside, terracotta roofing tiles are one of the heavier roofing options. They will require a solid roofing system that can increase the total cost of your home. Clay terracotta tiles are also generally installed on dwellings with only minor roof pitches. If your home has a steeper roof pitch or excessive snow dams could be a problem, terracotta tiles might not be the best option for your home.
Terracotta tiles certainly add an aesthetic aspect to any home and distinguish your home from the sea of asphalt shingles and metal roofing options currently dominating the landscape. However, you can expect to pay significantly more for this type of roofing option. Clay tile roofs cost anywhere between $10 and $25 per square foot, though the higher end of this price range is more common.
However, in most markets, a clay terracotta roof should boost the retail value of your home. According to Remodeling's 2019 Cost vs. Value Report, the average American homeowner spent $22,636 on a new asphalt shingle roof. Despite that investment, the new roof only increased the home's overall value by $15,427, on average. Though a terracotta tile roof would cost more upfront, homeowners could expect an increased value to their home, especially in high equity areas.
Periodic cleaning and sealing are essential to maintain a terracotta roof. Foundation Armor provides a strong, penetrating sealant that penetrates clay tiles' porous surface to form a water repellent barrier. These sealants do not change the clay tiles' color but help maximize the roof's water-resistance. You might need to periodically add an adhesive sealant between the individual roofing tiles if any leaks are detected. Home Depot sells an inexpensive and easy-to-use tile adhesive that you can use to seal any cracks or gaps between your clay tile roof.
When properly maintained, a terracotta roof can last for 100 years, if not more. Considering that the average asphalt shingle roof only lasts between 20 and 30 years, terracotta tile roofs are often the most cost-effective option in the long run. Your wooden roofing beams and structure might need replacement before the roofing tiles, in many cases. This situation could allow you to "re-use" the terracotta tiles after a significant roof structure renovation.
Terracotta roofs are more labor-intensive for installation. Generally, professional installers will mount a waterproof underlayment for added protection. Proper installation of each tile and the subsequent overlap with the next tile is essential to avoid water damage. The installation process will most likely include corrosion-resistant fasteners, drip edge flashing, and carefully placed gutters. For roofs with steep slopes, you will also probably need to install battens to help fasten your tiling into place. Clay roofing tile manufacturers will most likely include detailed instructions for how to correctly overlap and seal the tiles to ensure maximum water resistance.
Terracotta roofs are one of the most beautiful and durable roofing options available to homeowners. Though more expensive than other options, they offer unparalleled aesthetics, energy-efficiency advantages, and unmatched durability from a 100 percent natural material.
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.