Slate roofing shingles

[mfiore]

Anyone with any experience with installing traditional slate roofs?

I have a good book on the subject
(Amazon.com: The Slate Roof Bible: Understanding, Installing and Restoring the World's Finest Roof (The Slate Roof Bible, 2nd Edition) (9780964425811): Joseph Jenkins: Books

It states the proper underlayment is green, rough-sawn, local hardwood, commenting that plywood is the biggest mistake made buy rookies installing slate roofs. Although I have all the confidence in my insulation, I would like to avoid any flammable products (the fire inspector would prefer it as well!). I planned to use concrete board for the roof as well. How do you install slate shingles to that? The traditional method uses copper nails. I would think the concrete would be too hard to nail into with soft copper nails. What have others done?

[dmun]

Re: Slate roofing shingles

The practice of installing slates (or tiles) on furring strips is very ancient. The dentils in classic greek architecture are a reference to the protruding furring strips. I don't think a properly insulated oven will get hot enough to ignite these strips. One could imagine a substitution of rectangular aluminum extrusions and stainless screws, but really, why?

Talk to your fire inspector.

[RTflorida]

Re: Slate roofing shingles

We have a lot of tile roofs in FL. Most are cement based barrel tile, but many are low profile (flat) like slate. I see no reason why you could not use roof tile foam...the stuff holds great and meets high wind codes (hurricanes). The other method used is the above mentioned screw down to wooden slats (furring strips).
Here is a link to one of the MANY foam manufacturers, or just do a Google search for "roof tile foam"www.polyfoam.cc/wp/products/homeowner


RT

[dbhansen]

Re: Slate roofing shingles

Mike, this is off topic, but have you found a source for slate tiles? I've been searching this area and absolutely no one can get them. They're happy to install them for me, but not sell them to me.

I also was thinking of attaching furring strips onto the concrete board (after laying an underlayment) and attaching tiles to those. If you're looking for copper flashing, one place is josephjenkins.com. They have a drip edge with a raised strip built in.

By the way, a local contractor quoted me almost $3,000 for a slate roof ($50 per sq. foot ) and they wanted me to put 1/2" plywood down first!

Daren

[mfiore]

Re: Slate roofing shingles

No luck yet. I'm having some samples sent to me from the east coast. I've found places online, but the shipping is a killer.

Thanks for the tip on the copper. Joseph Jenkins is the guy that wrote the Slate Roof Bible.

[Breven]

Re: Slate roofing shingles

Hey guys...not sure if this well help or not, but I used 12 x 12 multicolored slate on my roof (home depot 1.25 ea). I cut them in half and used a thin set mixture fortified with latex. I don't get a ton of rain where I live (almost none) so I wasn't too concerend about water proofing. I sealed the tile real well just in case. It was pretty easy to do, but much more time consuming that a traditional slate. I had no choice in the matter...this was the cheapest way to go.

[mfiore]

Re: Slate roofing shingles

I also was thinking of attaching furring strips onto the concrete board (after laying an underlayment) and attaching tiles to those.
Daren

Daren, what are you referring to as underlayment? You already have cement board across your joists. Can you just put some furring strips on that, or do you plan another layer in between?

[Archena]

Re: Slate roofing shingles

Dumb question, why does he say green, rough sawn, local wood is what you should use? Wouldn't shrinkage play havoc with the nails?

[mfiore]

Re: Slate roofing shingles

Not sure I fully understand myself. I have no roofing experience, and can only go by what this single reference states. He explains that the boards

"simply dry in place after being nailed to the rafters. When fully dry, they'll have a gap between them of about 1/2" (wood shrinks more width-wise than lengthwise by a factor of seven).... when nailed properly, the boards will remain flat".

He goes on to explain that many hardwoods need to be laid green, as they get too hard when completely dried for the traditional copper nails used in slating. I think locally grown, green, rough sawn lumber is cheaper than kiln dried.

Again, I'd love to hear from those with slating experience.

[Archena]

Re: Slate roofing shingles

Ahh, I get it. Thanks!

Green, local, et al wood should be cheaper than dried - it is here, anyway.

Seeing as I have zero roofing experience w/ slate I'll quit bothering you now. Thanks again!

[MK1]

Re: Slate roofing shingles

Traditionally green, rough sawn red oak was used under many types of roofing. It's very difficult to drive a copper nail (even a common nail) straight in fully dried oak. Over a year or two the the green oak dries and clenches the nail shank creating a much higher pull-out value.
This is unnecessary and is no longed standard practice. We have the famous Peach Bottom slate local and it's always installed on plywood with large headed copper or stainless nails. There is no reason why you couldn't use stainless or hot dipped galvanized screws,(not electro plated) right on your framing if spaced close enough.
Fire-rated plywood is available but it's OK with code to paint the ply with Fire and Flame Retardant Paint and it's cheaper. You could then use underlayment (30lbs felt paper) and keep all precipitation out. Slate on lathe will admit a some moisture when it's wind driven.
You could most likely achieve decent pull out values with stainless deck screws driven into the cement board as long as it's not too windy at your oven location. If that's a concern use 2 layers of board and I think you'll be fine. You could also apply a polyurethane construction adhesive to the undersides as well and that would be bullet-proof.

Mark

[dbhansen]

Re: Slate roofing shingles

Daren, what are you referring to as underlayment?

Mark nailed it. I was just referring to felt paper or similar. Something to provide a little extra protection.

Daren