2. Stack two layers of 2" Polyso foil-backed rigid sheets of , staggered and taped at the seams, secured to the rafters with 5 inch screws. 3. then a layer of Tyvek-roofing membrane or self adhering GRACE, or GAF against water penetration. 4. Then 2x2 or 2x4 straps screwed down, which will accommodate sheet-metal snaplock brackets, 5.
Put down roof felt. Put full sheets of 2" on top of the sheathing and felt tacked in place. I know two layers of 1" would be ideal but that's more expensive per R. Finally, lay down 1x4s parallel to the ridge at 24" spacing and screw those through the , felt and sheathing into the rafters.
As Bill said, plywood (5/8" is fine) and 1"x4"s. 16"oc for the horizontals, but check your manufacturer for spacing of those. With no loads you can probably go 32" to 36" oc. The stack up for a roof may be different depending on what the the roof assembly consists of, and what type of metal panels you are using. The roof will have 4" poly over ...
One is a layer of plastic fiber mesh about 1/4" thick. This provides a path to exit for any leaks thru the metal roof, but provides little ventilation beneath the metal roofing. The better option is to install 1x4 purlins, creating a 3/4" thick air space. Purlins parallel to the eave seem called for, as the metal roof panels run perpendicular ...
1. In a conventional vented roof assembly — one with a ventilation channel between the underside of the roof sheathing and the top surface of the insulation — the roof sheathing can dry by giving up its moisture to ventilation air that enters at the soffit vents and leaves at the ridge vent. 2. In an unvented roof assembly with rigid ...
By Scott Gibson | November 9, 2015. Starting point for a low-slope roof: Kevin Hoene's original plan for the low-slope roof on his new home in Illinois. He asks for guidance as he wrestles with details for insulation and roofing materials. If only Kevin Hoene's choices for a new roof boiled down to a choice between an EPDM membrane and metal ...
Expert Member. MALCOLM TAYLOR | Feb 21, 2013 11:26am | #7. Other advantages of sheathing are that it provides backing for fasteners at roof penetrations and flashing, makes for a walkable roof for maintenance purposes, allows a thinner gauge of metal to be used and is more resilient to damage from falling debris.
It is almost flat (1:12 pitch) with 2x12 rafters, plywood sheathing and copper standing seam roofing. The insulation in the main roof is 3-1/2" batts plus 5-1/2 inch batts for a total insulation depth of 9" (that seemed like plenty in the 1970s). The rafters are 2x12 so there is a 2" air space above the batts. The main roof has inlet and outlet ...
I use two different manufacturers who supply a range of profiles of exposed fastener and snap-lock panels. They both provide span tables for the spacing of purlins for all their products. I don't know of any metal roofing that has to be installed on sheathing, although it's my preferred substrate, and here it is required for seismic resistance.
Now Rafter Span is a little more complicated. Once again, thank you for the answer. pt. fitchplate |May 29, 2014 07:08pm| #3. Lets pretend the roof design details are conventional and so the roof deck sheathing will be 5/8" to 3/4". Many metal roofing dealers specify minimum of 7/16" sheathing.