For years now, I have reviewed manufacturers’ published literature, trade magazine advertising, industry trade association newsletters, and wandered trade show floors with amusement as I witnessed the outrageous claims and descriptions of fake, faux, imitation, un-natural, look-alike, phony (not slate) shingles.

In light of the widespread failure of many of the fake “slate” shingles that have been produced and launched by the North American roofing industry (there are scores), the longevity, performance, and appearance claims made by their manufacturer’s “marketing tale spinner”s, when drawing comparisons with natural “real slate”, continues to astound me. Over the years, many of these products have been quietly withdrawn from the marketplace (leaving unfulfilled warranty claims in their wake) or spectacularly sued out of existence.

Many of the brand names of fake “slate” shingles have been sold multiple times in recent years amongst various general roofing material manufacturers. In many cases the warranty responsibility was not transferred for the brand seller to the brand buyer in these transactions, leaving owners with the failed roofs and worthless 50- year warranties.

I read recently of a 50-year manufacturer’s warranty for a roof installed in 2005 being expired by the manufacturer in 2010 because of curling at the edges. The company, obviously, no longer manufactures the product. Another manufacturer lists its only advantages over traditional slate as easy application, high resistance to roof traffic and affordability. It might just be me, but aren’t these the advantages of asphalt shingles, not improvements on real slate?

An article published in a prominent roofing industry magazine last year, by a very poorly informed author, spoke of the dwindling supply of natural and non-renewable slate, when, in fact, the choices of natural roofing slate products from around the world have never been greater. They went on to praise the environmental benefits of TPO, fillers, stabilizers, and inorganic pigments as more environmentally friendly than natural stone? Seriously eventually, in our non- perfect real world, all of these toxic materials are going to the dump! What can be more environmentally friendly than a natural slate roof being recycled into another product for reuse, or returned to the earth from which it came? The author of the article went on to explain that 15% of natural slates crack during installation and that natural slate only lasts 15-20 years, when, in fact, good quality (S-1 grade) natural roofing slate, as determined by ASTM International’s C-406 Standard Specification for Roofing Slate and promoted by the National Slate Association, has not more than 1% broken slates at delivery and has an expected service life in excess of 75 years. Anyone experiencing 15% breakage when installing slate, and getting a 15-20 year roof, is not buying or installing real slate!

My greatest disappointment is that we, as a roofing industry, have allowed the architectural community, roofing consultants, roofing material producers, roofing contractors and their supporting associations to hijack the term slate;  referring to it as if it is a  shape instead of a  material.  Slate is a sound, dense, 500 million year old metamorphic rock. It is not a rectangular, solidified puddle of warm goo of varying, assorted and sundry origins blended in a vat yesterday.

The fact of the matter is, look-alike shingles only approximately mimic the appearance of genuine slate and performance issues continue to be an industry problem. Fake slate shingles may be an asphalt shingle upgrade, but they certainly do not compare with natural slate roofing, except in weight, material price and cheap installation; and as stated previously, these are the advantages of asphalt shingles, not a benefit over natural slate with all its aesthetic, performance and environmental attributes.

Natural roofing slate is installed on substantial structures, buildings that are designed to last hundreds of years and engineered to meet these demands. The modest structural upgrades, to support the myriad of highest quality building materials that go into them, is inconsequential when measured over the lifetime of the building. Lightweight materials are designed for lightweight, disposable construction.

With material cost, you get what you pay for. Some fake slate shingles are considerably less expensive than real slate, but buyer beware their performance. Many will have an aesthetic service life of something less than three tab asphalt shingles. Surprisingly, many fake shingles are priced comparably to real slate, which makes their choice questionable, when again, measured against their actual (not laboratory estimated) performance and aesthetic service life. It’s possible that four fake slate roofs, or more, might be required to provide the same performance and aesthetic service life of one natural slate roof. Are there any fake slate roofs out there that have even seen 15-20 years of service (let alone 50, 75 or 100 years) and are still performing and pleasing to the eye?

Cheaper installation costs are commensurate with a fake slate’s  position on the roofing material hierarchy, as a step up from architectural shingles (maybe), not an advantage over the installation of a proven 100-year natural slate roof. The craftsmanship incorporated into the installation of a natural slate roof says with the building forever. The fast laydown of a fake slate roof leaves with the contractor’s truck when the job is completed.

I would impress on all in our industry to give natural roofing slate its fair due. It has been used as a roof covering for some of the world’s most significant buildings for over 2000 years with proven performance in the harshest climates. It is produced, specified, sold, and installed with pride by people at the top of their game in the roofing industry. Fake slate has its place, but roofing professionals know that it’s not in the same place as natural roofing slate. Let’s keep it real slate!


Article by David Large National Slate Association Senior Vice President