Metal roof installation

Brycen Wiedmer
1/29/2014
I am looking at installing a new metal roof on my home. I live on top of a hill and get quite alot of wind. My home currently has shingles with 5/8" (19/32") OSB for the roof sheathing over trusses that are spaced on 2' centers. I am looking at removing the shingles, installing 1 x 6's at a 21 1/2" center spacing screwed thru the OSB and into the roof trusses, and then filling in the void between the 1 x 6's with a 3/4" polystyrene board (Dow Scoreboard which is able to be snapped in 16" intervals). I would then be installing a synthetic ice/water shield over all the 1x6's and insulation before installing the metal roofing. Question 1: Are 1 x's acceptable for attaching the metal roofing to in high wind areas? I also plan on using long enough screws to go thru the 1 x's and OSB underneath. The entire reason I am getting rid of the shingles is the seal keeps coming loose in high winds, they start flapping around and eventually break off. If I am going to spend the $$ to go the route of a metal roof I want to make sure things are done right the first time. Question 2: Would installing an architectural standing seam roof over this application be acceptable in lieu of using a corrugated exposed fastener metal roof? Most standing seam roofs require a solid deck, but would the insulation between the 1 x's provide the needed support?
Todd Miller
Isaiah Industries, Inc.
1/29/2014
Hi Bryce. You always need to check with the manufacturer of the roofing to verify that what you're doing is okay for their roofing. This sounds reasonable though and it could be done with standing seam as well, again with manufacturer approval. Why are you intent on adding insulation? I am not saying it's a bad thing ... just curious what your motivation is.
Brycen Wiedmer
1/29/2014
The insulation is acting as a filler material between the 1 x's so I can install the ice/water shield without having any sagging in between. I am afraid if I put the ice/water shield over the OSB and install the 1 x's over that there would be a ponding effect if there are any leaks. The battens would hold the water from draining on out at the eaves. The other option I thought about was installing plywood directly over the OSB, but you would have the extra weight along with what I would believe to be a lesser material for the roofing screws to attach to.
Eric Novotny
An informed customer is the Best Customer!
1/29/2014
If the insulation is not designed to serve and insulation purpose, skip it. Covering the OSB with Ice/Water or underlayment should not create any ponding issues if the decking is solid and straight.

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