Slate Roofing Contractors Association

Slate Roofing Contractors Association



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The homeowner of the house above had these comments: [Fake slate brand] is saying that it was installed improperly. They are saying that the nails aren't located exactly in the "Nail Here" center. I have had 2 independent roofing contractors look at the roof - they have no stake in the game - and they said that [Fake Slate Company] is absolutely incorrect in their statement that there is improper installation. Every single one (almost) of my tiles are curling but I guarantee not every single nail is incorrect - not to mention there has to be some inch or two for margin. They also claim that the substrate is incorrect in that it is a 7/16 inch OSB which is "not per installation guidelines."  I am in Dallas, Texas area and the roofers I have talked with have said that 7/16 inch OSB is standard here."

Slate is a naturally occurring, fine‐grained, metamorphic rock able to be split into tough, thin sheets for roofing, flooring, cladding, and other structural purposes.

According to the American Standards of Testing and Materials, slate is a "microcrystalline metamorphic rock most commonly derived from shale and composed mostly of micas, chlorite, and quartz. The micaceous minerals have a subparallel orientation and thus impart strong cleavage to the rock which allows the latter to be split into thin but tough sheets." [ASTM C119]

According to European standards EN 12326–1:2004, roofing slate is: “[a] rock which is easily split into thin sheets along a plane of cleavage resulting from a schistosity flux caused by very low or low grade metamorphism due to tectonic compression. It is distinguished from a sedimentary slate [author's note: shale] which invariably splits along a bedding or sedimentation plane. Slate originates from clayey sedimentary rocks and belongs petrographically to a range which begins at the boundary between sedimentary and metamorphic formations and ends at the epizonal‐ metamorphicphyllite formations.”

According to the US Dept. of the Interior, "Slate is a microgranular rock derived from metamorphism of argillaceous sedimentary rocks (shale, siltstone, or claystone). It is characterized by excellent and prominent parallel cleavage which is oriented independently from the original sedimentary bedding. The essential mineral constituents are quartz, mica, sericite, or chlorite with assorted minor accessories. The sedimentary rock, shale, with which slate is sometimes confused, is composed essentially of the original clay minerals and cleavage is primary, parallel with the bedding. [US Dept. of the Interior, Bureau of Mines, 1968. Dimension Stones. William R. Barton. Information Circular 8391. P. 6.]

Slate is a geological mineral such as marble or quartz. There is no such thing as rubber "marble", or plastic "quartz," but there are a number of companies incorrectly, and in our opinion deceptively, calling their plastic, compostite, and rubber products "slate." They're selling products that only *imitate* or resemble natural slate roofing. These products do NOT perform like natural quarried roofing slate, and the misrepresentation of these fake products as "slate" is deceptive to the consumer and harmful to the slate roofing industry. We do not support fake slate products, nor do we recommend their use.

ASTM Rating of Roofing Slates


Pulling large slate block out of quarry.


Natural slate roof in Canonsburg, PA (above) at least 100 years old.

Commercial Misrepresentations of "Slate"

Composite "Slate" Roofing (Composite "slate" is NOT slate!)

Euroshield Roofing: "Vermont Slate": This is NOT slate! It is rubber roofing!

Aledora "Slate Roofing": This is NOT slate! It is a synthetic material!

Ecostar Majestic "Slate": This is NOT slate! It is a synthetic material!

DaVinci Bellaforté "Slate", Multi-Width "Slate", Single-Width "Slate": Not slate - it is composite roofing!

Inspire Roofing Products Classic "Slate": This is not slate!

Brava Old World "Slate": This is not slate. It is synthetic.

Engineered "Slate" Roofing: So called engineered " slate" is not slate.

Enviro "slate": Not slate!

CertainTeed Highland "Slate": Not slate.

Tapco"Slate" Classic: Not slate.

Vande Hey Raleigh Modern "Slate" is actually ceramic tile.

Ply Gem Engineered "Slate" is not slate.

TAMKO® Lamarite® Slate Composite Shingles: Not slate at all. Read a complaint. Here's another complaint.

MetalWorks® StoneCrest® "Slate": Not slate.


From D. B.: "One problem with man-made 'slate' versus natural quarried slate is that their color does not hold up to the UV. With mineral fiber/concrete tile (refuse to call them slate, because they are man made, so technically, they are tile) the color is a dye that is infused into the concrete during the manufacturing process. The tile itself may last sixty years or more but the UV leaches the color out over time. The same is true of the fiberglass tile. They are quite beautiful and unique when first installed, but after about twenty years you are left with a lifeless looking roof with the fiberglass glistening at you, almost mocking you (it's as if they are saying: you idiot!) Only natural quarried slate is the real deal. Why do you think all these companies are trying to reproduce a product that looks like slate? The rap that slate has gotten, and it's a fair complaint, is that there are just a few craftsmen left that know how to install the slate properly and are willing to take the time required to do the job correctly. Therein is the rub. We live in an instant gratification world. So the manufacturers produce a product that can be installed quickly and take advantage of the new high tech underlay that can mask poor workmanship for years and years. What I've experienced is that architects over the last thirty years have been burnt by the shoddy installation of naturally quarried slate. Their roof systems have turned into money pits for their clients, and the repairs are atrocious. But if you look at the slate that's been properly installed and has been hanging there hundreds of years, there is no substitute. There is no match for integrity and the majesty of naturally quarried Slate."


Fake "slate" curling on a roof (above).

From D.T.: Why Choose Slate Over Any Alternatives? There is no comparison to the finish of a natural slate roof. It’s difficult for any other material to compete with natural slate. The durability of a literally ‘rock hard’ natural material means that a quality slate roof will last a lifetime (or two), while the man-made alternatives need to be replaced once, twice or even three times over the course of the building’s lifetime. When it comes to aesthetics we’re clearly biased, but it’s hard to deny the style and finish of a quality natural slate roof. For us there simply is no comparison. Read more...

From J. J.: In short, I wouldn't touch fake "slates" with a ten foot pole. You can't go wrong with natural quarried (stone) slate roofing if it's correctly installed. Many of the fake "slate" manufacturers have gone out of business, but new ones keep popping up. It doesn't make sense to me to go with an untested product when one that is tried and proven and about the same cost is available.

From J. K.: So, synthetic "slate" [product name], [product name], [product name], [product name], and a host of others, have become a large percentage of my yearly business, and in many cases, my customers have already made up their minds that synthetics are the answer to their roof troubles before they even make one phone call to a roofer. The relentless marketing by the manufacturers, with claims of 50-75 year lifespans, less weight, colors and designer patterns, and ease of installation coupled with the consumers lack of understanding of natural slate roofs for the most part has left us as traditional roofers little choice but to install these or starve. Interestingly enough, we're even beginning to see synthetic slate specified in historic restoration projects on buildings with public interest- buildings with teams of architects and historical committees. Buildings with very old, original, and serviceable existing slate roofs but no mention of restoration: only replacement. During the installation process, we do the best we can to employ our knowledge of traditional roofing in an attempt to make these things last. Sadly, I still have my doubts: another case of the greatest thing until it's not. Another plastic product jamming up our landfills once it fails. Another discontinued line of shingles that is impossible to find repair components once it is compromised. More plywood, more ice shield, more headaches for the poor guy who has to tear it off. Don't get me wrong - these tiles look pretty damn good when they're initially and properly installed. The problem is this: after installing these and similar products as well as natural slate for 20+ years, and consistently driving by and looking at my past work - I see, with a trained eye, how much better the natural slate has aged, as well as its maintainability. The public needs to be informed and educated of the advantages of using natural, time-tested materials. We cannot continue to install untested materials that claim a long, maintenance -free life and sit back and hope that the manufacturers guarantee is really what they claim it to be.... When the shit hits the fan with this stuff, as it has time and time again- the roofer is left taking the blame, not the companies who produced the stuff.

Fake slate in Williamsburg Virginia

Fake "slate" in Williamsburg Virginia (above).


Sheriff's building in Palmyra, VA, with failed fake "slate."

It may interest you to know the series of events that lead me to a slate roof. My house was designed to have a natural color stainless steel shingled roof but during the two years of construction the price went from $300/square to $600/square. I then found a composite "slate" shingle which looks good, it's fireproof, is guaranteed for 50 years and comes in all the colors we wanted and we were back to $300 a square with a more natural look. It is listed as a top historical renovation shingle. I was a SUCKER! I have $20,000 of garbage "shingles" sitting at my shop. The composite concrete shingles are already showing hairline cracks and deterioration. After a little more research I found hundreds of lawsuits on this fake "slate" shingle. I have now joined many others in filing suit and will do everything I can to shut down that whole industry. My silver lining is that now I have real slate (at about the same price!) and I didn't install that garbage and find out 5 years from now.


From R. R.: These photos were taken yesterday and it was cool and rainy. You will have to zoom in to see curling corners. Looks worse when it's really hot. The rest stops on I-64 near Williamsburg, VA look much worse to me.





From L. S. and K.R.: Here are a few photos. One is a [product name] job in NY where the coating wore off of the cement in a couple of years. Without the coating it absorbs like a sponge, then freezes and breaks. The other two are [product name]. One is a color failure on Hilton Head where they are chalking out. The other one in Savannah is experiencing severe curling. It does not look as bad as it is in the photo, but the big deal is when exposed to wind driven rain, this roof flaps in the wind like a bunch of Patriot fans doing the wave in the Super bowl. It leaks when we get windy thunderstorms but they are waiting on a warranty claim to fix it. The big failure at present is [product name]. Here is a couple of photos. They are breaking at the nail line and falling off. It is worst in freeze zones I am told. The product was pulled from the market last year. I don’t know how many of these roofs are out there, but from what I can tell, they will all fail. Go to this site for the details on one such failure:




From R. M.: Installed in 2010 (now 2015):


From J.J.: Once billed as an ideal alternative to wood shake roofs, FireFree Rustic Shake, Quarry "Slate," Colonial Shingle, Quantum Shake and Quantum "Slate" panels offered high fire protection and came with some of the longest-term warranties available. Within just a few years of installation, however, the cement and cellulose fiber tiles on homes in Northern California and throughout the Pacific Northwest began to warp and twist. A Contra Costa County Superior Court judge awarded an $18.6-million class-action settlement in June of 2001 to homeowners of FireFree roofs manufactured and installed from December 1993 to November 1997. Homeowners with failing FireFree roofs covered in the suit had until Jan. 15, 2007, to file claims. Read more...

After only 17 years, this entire FireFree roof had to be completely replaced. The owner replaced it with natural quarried roofing slate.



Below: Fake "Slates," Pinehurst North Carolina