@pontiac428 , Thanks.
I suppose "long-lasting" is relative. This is a slate roof application with copper roofed dormers, gutters, valleys, etc. The current roof was installed in 1930, so >90 years outside in pollution. There are copper parts to the current roof and they have developed pin holes in them, copper rust holes. Stainless has a better CrOx protection layer, is physically stronger per thickness, and is much cheaper than Copper. But, it is harder to work with and is somewhat shiny! If the metal is wet or up against other metals it is not clear that any of them, SS or Cu, will last as long as the slate. Yes, I like the Copper patina as well, but...my current copper is leaking. When a slate must be replaced (slates breaks off at the nails or other places where it may have been stressed.. or the copper nails simply rust through and break off (commonly happens over the long term especially on steep roof installations where more of the weight of the slate hangs on the nail) allowing the slate to slip out, the patch method is to put a new or used slate back with a nail at the seam between the upper slates. This means water can leak through the nail hole, so they slip a piece of Copper (2" wide by 10-12" long) up between the slates covering the nail. The weight of the slate is suppose to hold the piece of Copper in place.... no nails in it... and this works for a while if not for a very long time. This copper turns brown or blackens so that it is not visible. Sometimes they use Al patch pieces, but it really does not hold up well and looks bad after a while. While slate is expensive, at $725/square and up, this pales when compared to the time intensive labor cost, 7-10x. The labor costs on short repair jobs is even more. On the other hand asphalt roofs only last ~20 years, and replacing them for 100 years adds up in cost as well as repeating nail damage (splitting) to the underlaying wood.
No, I will not be around to see it, but I cannot get past doing things right. Asphalt shingles really would not look good.
(Also, aside problems and facts: new nails into the old pine boards do not hold nearly as well as the original ones.... as the very old wood is now hard and brittle and tends to split. The cost of the slate is directly related to its life time, which is related to its hardness. A 1/4" thick slate can last 100 years, but if you get the good stuff that is really hard it can last 200-300 years. A New York bright red slate runs $1600 per square but can last >200 years. Slates wear out as they loose material density, leached out materials, and become porous and not as strong. Hence a hard, dense slate lasts longer. If you want it to last even longer get a thicker slate which is also heavier on the roof rafters, but will the nails last?)
Anyway, it would be nice if stainless could be used, but was not so shiny vs. the darker slate colors.
Dave L.
