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Bob_wewer (Bob_wewer)
New member
Username: Bob_wewer

Post Number: 6
Registered: 11-2013
Posted on Thursday, November 07, 2013 - 11:21 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I don't know but I always figured the old timers had it right. They rarely went below 8 on 12 for slate; 4 on 12 for standing seam and anything less: Flat Seam. I really like Fiberglass for low slopes. It lasts forever and looks really good.
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Joe Jenkins
Senior Member
Username: Joe

Post Number: 289
Registered: 07-2006
Posted on Wednesday, May 14, 2008 - 03:45 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

A traditional slate roof system can't be beat for longevity. Spaces between roof boards aren't necessary for ventilation - there is no real air flow there. That's one reason why tongue-in-groove lumber is successfully used on slate roofs. If you butt square-edged boards, they will develop gaps between them as they shrink underneath the slate, which is fine.

If the roof is going to last 100 years, what does the underlayment matter if it's only going to last a relatively short period of time? I would not focus on the type of underlayment, but on the roofing installation.
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carl sternecker
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Username: Stoney

Post Number: 2
Registered: 05-2008
Posted on Tuesday, May 13, 2008 - 11:52 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Joe and others,
Thanks. We have asphalt shingles at present.

Do any of you care to comment on Tru-slate,s system with stainless brackets and a heavy plastic under each row of slate? What about Nu-slate which uses a system of metal battens.

Also any suggestions for a breathable underlayment under the new verticle 2x4 battens? Is Tyvec tar paper or R-wrap OK?

I like the suggestion of boards as horizontal members but would like to leave some space (3 inches) between each board (for air flow and venting) or do you think the 1 inch T&G is best?
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Joe Jenkins
Senior Member
Username: Joe

Post Number: 287
Registered: 07-2006
Posted on Tuesday, May 13, 2008 - 10:58 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Carl - is there slate on the roof now? What about on the 4:12 slope? I would slate the whole thing and use a minimum 4" headlap on the 4:12. Maybe a larger headlap. I have a 10:12 draining onto a 4:12 on my house. I installed the roofs in 1984 and have had ice damming twice on one edge of the 4:12. Some day I may take the slate off the 4:12 and reslate it with a 5" headlap. I used inadequate headlap when I originally slated it, but have been able to prevent leakage by slipping bib flashings under the slate slots.
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carl sternecker
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Username: Stoney

Post Number: 1
Registered: 05-2008
Posted on Tuesday, May 13, 2008 - 01:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Hello Joe,
We live in northern Wisconsin and are needing to re-roof our home. The house has cathedral ceilings at a pitch of 14/12. This pitch changes to a 4/12 over a kitchen and porch area. We have had a history of ice damming in part because much of the insulation has settled and blocked any air flow. I'm thinking of building up a cold roof on top of our existing sheeting. We woud remove the shingles and put 2x4's (on edge) on top of each 2x12 (douglas fir) rafter. Then we plan on resheating with 5/8 osb. We would even change the pitch to about 5/12 if this seemed necessary.

We are looking at the tru-slate system using new sheeting or greenstone slate using the nu-lock system of battens and not install new sheeting if possible. In either case I'm wary of the impermeable membrane underlayment and would like to use something like attiic wrap or tyvec house wrap as underlayment for the entire roof. We plan on densepacking all the roof cavities (under the existing sheeting) with cellulose. I'm impressed with the way you think and would appreciate your comments or suggestions.

P.s. The house has about 200 ton of native rock in it, each one was hand picked by my wife and me. I would be happy to call you if you need more detail or clarification.

Thank you. Carl Sternecker phone 715-874-6264.
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Joe Jenkins
Senior Member
Username: Joe

Post Number: 236
Registered: 07-2006
Posted on Friday, March 07, 2008 - 11:09 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

We do the same thing with stress skin panels. We go over them with vertical furring strips, then cover those with boards before slating. We have also screwed furring strips into the OSB, over felt, horizontally, spaced as nailers for the slate, and nailed the slate directly into the furring strips, which is quicker and cheaper and still allows for a 3/4" solid board nailing medium for the slate.
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Walter Musson
Advanced Member
Username: Walter_musson

Post Number: 43
Registered: 07-2006
Posted on Friday, March 07, 2008 - 10:59 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Yes Joe that is correct.
There are stress skin panels over the rafters on this timberframe home. It was dried in with felt temporarily until the sheathing boards arrived.
The felt was removed as they worked the boards up each level.
Anyone can follow our progress in the next few weeks as we install the slate by checking this thread on the Fine Homebuilding website.
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Joe Jenkins
Senior Member
Username: Joe

Post Number: 234
Registered: 07-2006
Posted on Friday, March 07, 2008 - 10:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Here's a copy of one of the photos. Underneath the underlayment is an OSB deck. The nailers are probably right over the rafters. They're covered by 1x10 t-i-g boards - looks like 3/4". Is that correct, Walter?

covering OSB with boards on a slate roof
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Walter Musson
Advanced Member
Username: Walter_musson

Post Number: 42
Registered: 07-2006
Posted on Friday, March 07, 2008 - 09:53 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Kurtis or anyone else,
All you need to do is set up an account --Free -- just your e mail and a screen name like Joes site here.
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Kurtis Hord
Member
Username: Kwhord

Post Number: 30
Registered: 10-2006
Posted on Friday, March 07, 2008 - 09:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Can you re-post the picture here? I don't have access to the fine homebuilding site...
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Walter Musson
Advanced Member
Username: Walter_musson

Post Number: 41
Registered: 07-2006
Posted on Thursday, March 06, 2008 - 01:35 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Joe,
Yes they are. I'll send some out to you in a few days.
Walter
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Joe Jenkins
Senior Member
Username: Joe

Post Number: 233
Registered: 07-2006
Posted on Thursday, March 06, 2008 - 11:33 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Walter - are those your photos on Fine Homebuilding showing the battens over the OSB covered by 1x10 t-i-g? If so, can you email me copies that I may use in the next Traditional Roofing? That illustrates a good solution for when the roof deck is inadequate for slate.

joe at josephjenkins.com
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Joe Jenkins
Senior Member
Username: Joe

Post Number: 232
Registered: 07-2006
Posted on Thursday, March 06, 2008 - 10:58 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Now that the IWS is already installed, he can install the slate over it. However, whether the exterior vapor retarder (IWS) adversely affects the roof ventilation capabilities before the IWS cracks up (and allows air through), remains to be seen. If the building has a good internal vapor barrier (assuming it's in a northern state), then any condensation interior to the roof sheathing should be minimized.
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Walter Musson
Intermediate Member
Username: Walter_musson

Post Number: 40
Registered: 07-2006
Posted on Wednesday, March 05, 2008 - 01:27 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Heres a link to a Fine Homebuilding site with a similar situation
http://forums.taunton.com/tp-breaktime/messages?msg=99268.224
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Holly Johnson
New member
Username: Hmj

Post Number: 1
Registered: 03-2008
Posted on Wednesday, March 05, 2008 - 11:17 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I have read many of the posts regarding the disadvantages of plywood decking and I&WS as an underlayment for slate, and I convinced. However, I have client who's house is currently under construction and he has a 14:12 pitch roof with 2 x 6's and I&WS and wants to add a slate roof (he was initially going with asphalt shingle). Now that he has changed his mind I am trying to advise him on what to do with his roof to prepare for the slate. He knows about bracing the roof. How should I advise with regard to underlayment and insulating/venting????

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