Concerning tile roofs in Miami, ask ten roofers, “Who makes the best tile?” You may get ten different answers as they will consider many criteria including strength, price, aesthetics, warranties and technical considerations such as water absorption rates. Residents may find their most useful resource is all around them. When choosing tile South Florida serves as the perfect sampler where every style imaginable is represented. Tile roofs are extremely durable, giving homeowners piece of mind knowing it can’t rot, has a Class A fire rating and stands up to the area’s salty air and blazing sun.
HISTORY Of TILE ROOFS
Tile roofing originated in China over 10,000 years ago and appeared in the Middle East soon after. Roof tiles in the U.S. can be traced to European immigrants, primarily the Dutch of the Northeast in the mid-1650s and Spanish missionaries of California in the early 1700s. Evidence of clay tile roofs has been found in the settlements of Jamestown, Virginia and St. Augustine, Florida.
The invention of concrete roof tiles is attributed to Adolph Kroher in mid-nineteenth century Bavaria. Production by hand prevailed on a small scale well into the 1900s and became available in the U.S. around the turn of the century. However, they didn’t become popular until decades later as production methods improved.
Tile Roofs of Miami
Clay tile roofs in Miami began at Viscaya, John Deering’s winter home built on Biscayne Bay in 1916. His brother Charles then built The Stone House in 1920 on the Deering Estate at Cutler. Also in 1920 developer George Merrick began his creation of an “old world” city – Coral Gables. All of these men utilized salvaged Cuban clay tile. Merrick went to Cuba to buy as much as he could and discovered they were hundreds of years old, having originally come from Spain as ship ballast. Knowing this, Merrick went to Spain and salvaged the ruins of estates and monasteries there. The signature look of clay tile in Miami was born.
During the forties and fifties two types of concrete tile roofs became very popular – 9″ flat and pan & cap barrel. Both were available in many colors including a popular Spanish Red but white became the dominant choice and was considered more contemporary, fitting the Art Deco style. Many of those old barrel tile roofs are still in service today because they were mortared together, piece by piece, allowing very little water to penetrate to the underlayment. Unfortunately, concrete absorbs water so, when it rains for prolonged periods, the tile becomes saturated and “leaks” from underneath. As years went by people started painting them and, in effect, waterproofed their roof.
This brings us back to the reason Historic Cuban Tile Roofs last so long – they were also installed using the pan and cap method and, being of such high quality, absorb almost no water. These classic pan and cap, concrete and clay barrel tile roofs had one draw-back. The system, with its overlapping pieces and large amounts of mortar, was expensive and considered high end.
TODAY’S TILE ROOFS
In 1961 the first high pressure, extruded, interlocking concrete roof tile machine was operational in Freemont, Cal. This signaled the rise of concrete tile as a major player in the American market. Extrusion methods were adapted to clay and soon there was a parade of new manufacturers making a tile roof much more affordable for the average homeowner.
Today concrete and clay tiles are immensely popular in the southwest, California, and the southeast including, of course, South Florida. Energy efficiency, longer life cycle, and aesthetic appeal has made tile roofing the dominant choice for homeowners looking for an upgrade over asphalt shingles. Clay tile is manufactured in Spanish S, barrel, and flat profiles. Spanish S, which emulates the pan-and-cap style with larger and fewer tiles, has long been the popular choice in South Florida. Concrete tiles are available in high profile S-tiles; medium profile double-S; and flat.
Clay tiles are available in colors ranging from terra cotta to peach, brown, even pink and are sometimes fired with a manganese solution to create a scorch on the surface. This style is sometimes referred to as fume’ and is very popular in South Florida. They also can be colored using “slip” – a thin, runny clay. A more expensive way to color clay tile is glazing whereby any color is possible.
In the past, it was easier to make concrete tiles from grey cement and paint the top surface with slurry, a loose mixture of colored cement. Concrete tiles could also be colored with iron oxides in the mix but was expensive due to manufacturers’ struggle to perfect the process. Today’s machinery accurately controls quality and ensures consistency. Slurry and color-through are priced almost the same now as the industry converts to color-though as their main product.
Roof Tile Installation Methods
Slope, deck type, climate, local codes and manufacturer’s specs all help determine the installation method to be used. Common methods throughout the US include lug-hung, mortar-set, nail-on, screws, clips, adhesives and polyurethane foam. Nails are the least expensive and most widely used installation system but are not recommended in South Florida. Very popular among builders of sub-divisions in west Miami-Dade and Broward in the 90s, nail-on systems caused numerous leaks as the method is prone to human error and simply incompatible with roofing in a sub-tropical climate.
The mortar-set system had predominated since Viscaya until Hurricane Andrew exposed its inadequacies in 1992. Mortar-set is a fine system if the underlayment and tile are kept wet and if the mortar is consistently mixed to correct ratios – clearly too many “ifs”. Chemical companies quickly developed an almost fool-proof polyurethane foam adhesive system which only requires that the underlayment and tile be clean and dry. Poly-foam is much faster, lighter and provides excellent adhesion of the tiles to the underlayment.
Underlayment is applied to the deck prior to setting tile and is the primary water-proofing component. South Florida homes are generally designed with relatively low slope for wind resistance and this allows water to filter through to the underlayment, requiring a robust system.
Asphalt saturated felts have been the most common underlayments for over a century. Roofers commonly refer to them as 15 lb, 30 lb and 90 lb which reflect a pound per square standard. 30 lb is adequate in other parts of the US but here it is just the first step. For several decades the 30-90 hot-mopped system dominated as the preferred underlayment of Miami roofers. It entails fastening 30 lb. felt to the deck then hot-mopping a layer of 90 lb. mineral surfaced roll roofing, creating a tough waterproof membrane. The problem with the 30-90 system is its susceptibility to the high temperatures generated between the tile and deck. Over the course of approximately 20 years the effects of thermal shock, constant expansion and contraction due to temperature changes, causes cracks and splits in the membrane.
Lately the trend is shifting toward self-adhered synthetic underlayment. This new generation of products is characterized as light-weight for ease of installation, highly resistant to tearing and high temperatures, very flexible and more durable than the 30-90 hot-mop method.
Concrete or Clay?
Concrete and clay roofing tiles are the two most common options available and the debate over which is better continues after almost 100 years. Each has benefits and considerations that should factor into choosing a particular tile.
Clay tiles are more expensive than concrete which are easier to manufacture and install. Clay tiles can last for many decades and maintain their waterproofing capability. Their density gives them an almost zero water absorption rate which allows them to stay algae-free much longer than concrete tile but also makes them susceptible to breakage from projectiles during storms, falling tree limbs, or people walking on them incorrectly. Fumigators are notorious for damaging clay tile roofs while tenting.
Concrete tiles are stronger and last 30 to 60 years depending on local conditions and level of maintenance. After a few years or so the factory finish on a color-through or slurry coat tile will wear off and develop algae growth. This is when most people pressure-wash the roof which strips a color-through tile, increasing its water absorption rate due to concrete’s porosity. During lengthy storms a stripped tile will become 100% saturated and drip water from its underside. Pressure-washing slurry coat tile will remove some of the finish, which is essentially paint, each time and several cleanings may expose the base concrete. Proper maintenance involving the right cleaning and sealing products applied by a qualified roofing professional will greatly extend the life of the finish and maintain water-shedding performance.
The aesthetic appeal of clay tile is primarily why many homes feature this style. In areas like Miami with homes featuring Spanish and Mediterranean architecture you will see a large percentage with clay tiles. The look of terracotta is worth the downsides for many homeowners. Concrete roof tile, however, is available in several different colors and styles including some convincing versions which mimic clay Spanish S. Standing in a South Florida neighborhood, one may be surprised to find that while they thought all the homes had clay tile, many are actually made of concrete.
An Excellent Choice
A perceived downside of tile roofing is its steeper upfront costs but when spread out over a properly installed roof’s lifespan, tile roofs are quite economical. Yes, tile roofs cost almost twice as much as fiberglass shingles – and they can last at least twice as long.
Installations and repairs are best left to professionals with local experience working with tile. Humans are usually a tile roof’s greatest enemy because people are the perpetrators of bad installations and improper maintenance besides not knowing how to walk on them. Miami roofers will tell you the best thing for your tile roof is to stay off it.
Properly installed and maintained tile roofs are attractive, energy efficient and relatively economical roofing systems that offer homeowners decades of protection and value.
Michael Slattery is a Florida Certified Roofing Contractor and President of Roofer Mike Inc, a roofing company in Miami, FL.