Slate roof identification

[Ponyboy]

Just looked at a slate tile roof. Very rare for the Seattle area. The roof is in need of repairs and cleaning. I need help clarifying the origin of the slate. The home owner insists it is Maine slate, but it sure looks like New York / Vermont slate? What do you experienced slate roof inspectors have to say?

The roof is heavily covered with moss. Can the roof be cleaned. I figured a contractor would have to use a man lift to perform cleaning and repairs.

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[mgbinspect]

I'm afraid I can't help you with the actual slate, although when still doing disaster restoration contracting I had to deal with all this. I left materials identification up to my roofers. A lot of beautiful slate comes from Pennsylvania, but I believe you'd see some greenish slates as well in the mix.

There is a lot of slate roofing in Richmond, but very few good roofers familiar with the old school methods of repair. Here's a slate replacement tip that one of my really old and respected roofers taught me: Avoid slate replacement with the use of metal clips, which is a rather unsightly and temporary fix, since the turned over hook portion of the clip that holds the bottom of the new slate in place eventually rusts away releasing the slate. The proper way to replace slates is by nail and bib. The new nails and holes actually line up with the gap between the slates above. Then, a copper bib with diagonal cuts (points turned downward and down slope to grip the slates) is slid under the upper slates to cover (bib) the nail heads. When the copper turns, the bib blends in quite well with the slates to virtually disappear. This is the Cadillac replacement method, which is quite permanent, and most roofers don't do it.

If a roofer insists upon this method, you know he's your man.

Mike

[Bill Kibbel]

It's possible SOME of the slate is from Maine. Much of it however, is from Vermont and New York. Red has only ever been found/quarried in NY.

For cleaning, moss that thick needs to be scraped first, with a plastic scraper. An experienced slater, with the right equipment, can be all over that roof without a lift.

[Brandon Whitmore]

So, did you walk the roof?[:-slaphap

That's a cool find out West. I've never inspected one.

[Ponyboy]

So, did you walk the roof?[:-slaphap

That's a cool find out West. I've never inspected one.

Yeah right!! Because of the steep pitch you could see almost the whole roof from the ground. I spent a lot of time learning about slate roofs the past few days. Many repairs on the roof have been done with exposed strap hangers, bad. The problem will be finding an experienced slater in or near Washington. Anybody know of a slater who would travel to Seattle? Lets say my client has funds and wants to retain this classic roof.

[JeremyDP]

For cleaning, the big box stores carry something called JOMAX Roof Cleaner and Mold, Mildew Remover.

Works like a charm. Just follow directions.

[kurt]

So, did you walk the roof?[:-slaphap

That's a cool find out West. I've never inspected one.

Yeah right!! Because of the steep pitch you could see almost the whole roof from the ground. I spent a lot of time learning about slate roofs the past few days. Many repairs on the roof have been done with exposed strap hangers, bad. The problem will be finding an experienced slater in or near Washington. Anybody know of a slater who would travel to Seattle? Lets say my client has funds and wants to retain this classic roof.

I've been reading this, but waited 'til Kibble weighed in. Listen to him. Slates are different animals. I've been looking at them for over 20 years, and am still learning stuff.

As far as what you should tell your client, tell him to expect annual repairs. There's always going to be a slate sitting in a gutter somewhere that needs to be reinstalled.

Don't listen to the stuff about "old felts" being a problem; I used to believe that, but old felts are almost always just fine, especially on this steep a pitch. I've worked on 100 year old felts, and they're always fine.

After that, too much to smash into a simple forum outline. Keep reading......

[mgbinspect]

So, did you walk the roof?[:-slaphap

That's a cool find out West. I've never inspected one.

Yeah right!! Because of the steep pitch you could see almost the whole roof from the ground. I spent a lot of time learning about slate roofs the past few days. Many repairs on the roof have been done with exposed strap hangers, bad. The problem will be finding an experienced slater in or near Washington. Anybody know of a slater who would travel to Seattle? Lets say my client has funds and wants to retain this classic roof.

Yeah, the strap hangers are nasty looking and really don't last all that long. I've actually seen them fail and dump the slate again. I think they're a really poor fix.

And, as Kurt has said, Bill Kibbel, by virute of his extensive historical background, knows more about slate roofing than anyhone else. That's for sure.

Richmond has a lot of slate roofing, not only on the old historical row houses, but a lot of homes built in the 30's and 50's out in the suburbs. My experience with it has to do with years of insurance related repairs, due to fire and storm damage, in which I had to make it look like it never happened. And, of course, owners of 100 year old historical homes, when having insurance related repairs, want it done perfectly. So, during those years I kinda got a crash-course in slate roofing. But, I'm certainly no expert - plenty left top learn.