Thread: Slate of Asphalt Shingle

Heres something I've never seen before.

This is the first slate roof I have seen over Asphalt Shingle.

Roof is in pretty good condition. I estimate 25 - 40 years old.

Anyone familiar with this installation?

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Well if someone were to spend that sort of money for slate shingles why in the heck would they install it over asphalt and the extra weight, ventilation, and manufactures preferred installation methods.

Originally Posted by Raymond Wand

Well if someone were to spend that sort of money for slate shingles why in the heck would they install it over asphalt and the extra weight, ventilation, and manufactures preferred installation methods.

One additional layer of asphalt shingles is allowed over a layer of asphalt shingles, but slate over asphalt shingles???

I would be greatly concerned about the additional weight.

At the turn of the century, slate roof tile was installed in a manner where it was the waterproof barrier. Using this method and a 16 x 10-inch slate roof tile a minimum of 221 tiles per square was required. This translates into a dead weight load in excess of approximately 1200 pounds per "square" for just the roof tile.

It would be interesting to see two things: what the attic looked like, and the look on the face of the real estate agent when the client is told "the roof appears to be improperly installed." I once found 5 layers of asphalt shingle - three roofers had taken advantage of a very elderly woman - with associated collapse of roof framing in the beginning stages. Perhaps tighter regulation of roofing contractors is in order. OR more inspections!

That's funny, And stupid!! I have seen many asphalt over slate. What a mess!! But that's a new one. Must have had a bunch of slate that fell off the back of a truck along with some pro roofers to install.

Attic looked good. Decking and rafters in good condition. I was able to see the underside of the asphalt shingles from the spaces between the plank sheathing.

I did not call this out as an improper installation. As far as I can tell this is permitted. The roof doesnt leak. Slate tiles are in fair condition.