Standard Shingles Over Slate

[Terence McCann]

What are the thoughts on putting standard shingles over a slate roof.

I called the municipalities building department and they said as long as the shingle manufacture says it's OK they have no problem with it.

Tanks....

[kurt]

I see it a few times a year on the old stuff in the City; sometimes 2 or 3 layers over the old slate. It seems to work OK, but it is a sorry excuse for roofing. It makes the (eventual) tearoff a much larger job.

[Brian G]

How in the hell do they nail the shingles down on top of the slate?

Brian G.

[hausdok]

very carefully?[]

OT - OF!!!

M.

[kurt]

I always wonder the same thing. What's strange is that the slates don't look shattered; they hold the nail(?).

I suppose it's like nailing on steel "pole barn" roofing; hold the nail straight, & hit it really HARD.

[Steven Hockstein]

What about the added weight? I would be concerned about the slates, asphalt shingles and snow load.

[kurt]

That's the other surprising thing; these places are always old, 2x4 rafters, no ridge beams, (maybe) collar ties, etc., but possess no significant sag. One thing they usually share is a steep pitch, which is the balm for the (otherwise) goofy mess of roofing.

[Brian G]

Sounds like an all-around bad idea to me. Duh! [:-dunce]

[crusty]

IRC 907.3

[Gerry Beaumont]

Hi to all,

I am still trying to figure out how you get a nail through a slate ??

In the mean time for those who don't have IRC available, the clown from "The Simpsons" ref means:

907.3 Recovering versus replacement.

New roof coverings shall not be installed without first removing existing roof coverings where any of the following conditions occur:

1. Where the existing roof or roof covering is water-soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.

2. Where the existing roof covering is wood shake, slate, clay, cement or asbestos-cement tile.

3. Where the existing roof has two or more applications of any type of roof covering.

Exceptions:

1. Complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building's structural system and that do not rely on existing roofs and roof coverings for support shall not require the removal of existing roof coverings.

2. Metal panel, metal shingle, and concrete and clay tile roof coverings shall be permitted to be installed over existing wood shake roofs when applied in accordance with Section R907.4.

Regards

Gerry

[hausdok]

Ummm,

Then you're back to what the local municipality allows versus what the code says. A few years ago I found six layers of asphalt roofing on a 100 year old tudor in downtown Seattle. I called the code guys downtown and asked them how this could occur when everyone knows that more than two layers is not allowed. "Easy," the guys said, "We never adopted that provision of the code. If a homeowner wants to put ten or even twenty layers on we don't care. He's doing it at his own risk."

I was flabbergasted, but there it was.

ONE TEAM - ONE FIGHT!!!

Mike