new standing seam metal roof ?s

[300UGUY]

I was always told to 'double strap' a metal roof. put a barrier on the sheathing, fasten vertical strips through the sheathing into the rafters, then put crossways straps (purlins) on top. Fasten the tin to the purlins. The purlins run the right way to fasten the tin, and the vertical strips give condensation a way to drain off of the roof. I've also been told that this method will result in more condensation because of the air flow, but will also get rid of the condensation quickly, whereas tin applied directly to the sheathing will trap moisture, since there is little airflow. Many barns have been built with no sheathing- and they definitely drip water inside, depending on the atmospheric conditions. I have to admit- At this point, I'm not sure which method is better. I need to decide, though, as I'll be roofing a barn in another month or so!

Question- Why are the materials for standing seam so much more? It's usually at least double, just for the materials.

I'd like to know myself. Metal roofing seems expensive for what it is.

 

[davedj1]

Well first of all, all metal prices are up so that doesn't help. Also they have long warranty periods. Standing seam is more labor intensive than panels too. Especialy if you have lots of vallies or different roof lines.

 

[BeezFun]

I was always told to 'double strap' a metal roof. put a barrier on the sheathing, fasten vertical strips through the sheathing into the rafters, then put crossways straps (purlins) on top. Fasten the tin to the purlins.

Your suggestion is consistent with how siding is supposed to be put up. The felt paper (or Tyvek) is the water barrier, and there's supposed to be a small drainage between the siding and paper. This gap can be created with mesh products that look like nylon scrubby pads, or the same way you suggest with thin vertical furring strips.

I have metal roofing directly on the purlins in one of my buildings and I agree with you, it sweats under the right conditions. I've always thought it was because there's horses in there, they create moisture when they breathe and they pee in their stalls. Then the moisture in that warm air condenses out on the cold metal. I guess if you just had a dirt floor you'd still have moisture, probably not as much.

 

[BeezFun]

I have to admit- At this point, I'm not sure which method is better. I need to decide, though, as I'll be roofing a barn in another month or so!

Here's the installation video from the company that supplies Menard's roofing, they show it screwed directly to 30# felt paper, or directly over extruded insulation:
Installation video

 

[nickel plate]

epete,
That's a nice looking home you have but your roof is not a shed design, it is basically a gable roof. A shed roof is half of a gable with no ridge line, as in the diagonal edge of a right triangle. A shed roof can either completly cover a structure from top plate to top plate with a single or multiple sections of full length mono pitch(s) or extend off of ninety degree walls. Probably other applications but these two are the most basic.
This is an example of an upper gable and two lower sheds.

 

[Pixguy]

I had this system installed on my garage shown below just this past May. Not sure of the sq. ftg. price but my 26X32 roof with dormers front and back was 4k. Nobody could come close to their price.
I used a co. out of Vt called Iron Horse using the Englert system. It was quite the 5 hr. performance and they formed and installed the roof. The siding guys wanted to them to put the flashing in the valleys so they could side and not have to walk on my 12/12 metal roof. But the roofers form the valley pieces together with the roof, all one pc., so not to have the chance of leaks.

We also installed Grace's TriFlex underlayment which was nice to walk on.

I love it and would recommend these guys.

 

[LeadPoison]

I have installed numerous SS roofs for a living. I have removed older SS roofs and have observed what went wrong and why they failed.

My advice is to install a 5/8" CDX deck, install a non-granulated ice and water shield, install a SS roof with a higher than normal seam if you live in a snow climate, and install a butyl caulk tape in each seam. You should be good for a looooonnnnggg time.