Replies

1. 
   Guest_ | Jul 22, 1999 12:23am | #1

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   Hi Marcus,

   I don't see the benefits of ventilation over the styrofoam and you already have a gap for ventilation between the wood shakes or shingles.

   I also don't see the need for any additional VB other than the plywood on the top and the wallboard underneath. The solid panels of SM are all you really need for this purpose. Whatever you do, do not install poly on both sides of the roof detail, something has to breath.

   Quiet a detail, BTW.

   Gabe

1. 
   Guest_ | Jul 22, 1999 09:48pm | #2

   *FreddyL,What a crock of s**t. The only accurate part is your building something that failed within 14 years which is probably the norm for you.Gabe

1. 
   Guest_ | Jul 23, 1999 08:10am | #3

   *Marcus-This is a very unusual roof detail in my neck of the woods. Was this designed by an architect, or an engineer? Have they used this design successfully in the past? Or are you and the customer the guinnie(sp) pigs? Seems to me with a little more thought you could accomplish the same look without the hodge-podge of perlins and battens. I think a double vapor barrier is a bad idea in any case. John

1. 
   Guest_ | Jul 24, 1999 08:12am | #4

   *Seems like a heck of a lot of wasted timber in this design and not a very good space set up for insulating.

2. 
   Mark_Helling | Jul 25, 1999 05:02pm | #5

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   How about using the 4x8s, on top of those use foam filled panels--styrofoam sandwiched between 2 sheets of OSB or OSB and drywall. If it's a wood ceiling and exposed 4x8s you want, put down a layer of T&G 1xs before setting the panels. This is how "Norm" built the shop on a recent "This Old House" episode. They used panels that were something like 4x16. What do you guys think?

3. 
   Marcus_Mueller | Jul 25, 1999 05:02pm | #6

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   Question: If I am building a roof system using 4x8 rafters and 2x6 purlins on top in vail, CO. would it be better to fully insulate the 2x6 purlin area with rigid insulation (w/ an R/40)and put vapor barriers on both sides, or would it be better to insulate the 2x6 purlin area w/ 4" of rigid insulation and vent the remainder of the 1 1/2" to the gable ends of the 10:12. Which system will be better for condensation. I would imagine the fully insulated roof w/ an R-40 would act as a super insulated roof and perform better in the long run. Any suggestions would be welcome. I have attached a .gif file of a detail to show the construction