There is nothing quite as durable as slate roofing shingles. In fact, if the ASHI Technical Journal may be believed, they may last well past the consumer’s lifetime. So why should homeowners weigh their options carefully before investing in slate shingles?
Durability: 40, 50 or 175 Years?
There is little doubt that slate shingles outlast their asphalt cousins. The writers of the ASHI Technical Journal explain that Virginia’s “Buckingham” line actually has an average life expectancy of 175 years. Even so, there is a bit of a downside to this material choice.
Not every slate shingle is created equal. In fact, Pennsylvania-quarried slate shingles may only come with a life expectancy of 40 to 50 years. The disparity has to do with the material’s makeup.
Tip: Match the price tag with the disclosed durability rating. As a general rule of thumb, buy the shingles from a company that has been in business for a long period of time. A fly-by-night outfit will not be around to honor a slate shingle claim some 10 to 15 years after installation.
Weathering: Unfading vs. Semi-Weathering
A slate roof is a long-term investment and remains a stunning asset to the home’s overall appearance for decades to come – if the homeowner chooses the slate roofing shingles with weathering in mind.
Unfading shingles, so the Slate Association explains, withstand the elements and keep looking great and close to their original color hues – they also command a high cost. Semi-weathering shingles can start out looking green but eventually turn brown or mottled.
Tip: Choose slate shingles with an understanding of what their eventual color will be (after weathering), and do not base your buying decision on the current look – unless you are prepared to pay extra for an unfading slate shingle type.
Cost: Material plus Labor
The homeowner in search of a roof replacement material already knows that the slate shingle is the Rolls Royce of roofing materials. With asphalt being the economy covering, tile and slate bring up the upper end. Cornell University estimated in 1997 that a 100-square-foot slate roof area would require an expenditure of $320 to $1,200 for materials alone.
By comparison, asphalt shingles would only cost about $20 to $140 per 100 square feet. What is not disclosed is the need to potentially reconstruct the attic structure to hold the 900 plus pounds of material weight per area. Asphalt, which is much lighter, only places a weight addition of 195 to 430 pounds on the attic.
Tip: When inviting labor and materials estimates, have the roofer also examine the attic and include any additional supplies and man-hours that it will take to prepare the structure for the added weight. I got this from a friend who works for a roofing company in Marietta, so it’s really something that you should ask for beforehand when you are considering a home roof repair.
It is clear that slate roofing shingles are a durable choice for the homeowner who has the funds to opt for the best shingles available and who also does not mind spending a little extra to adequately prepare the underlying structure. For the homeowner with a tighter budget, a slate roof may not be the right choice.
ASHI Technical Journal: “Slate Roofs”
Slate Association: “North American Roofing Slates”
Cornell University: “Roofing Material Comparisons”