If it's cheaper than shingles it's because you're comparing shingles with labor/profit versus metal material only. My quotes for someone else doing the roof were in the low 20k's and none of the bidders could seem to read the plans that specified peel n stick underlayment and special fastener type for SIP panel base. It took me considerable time and effort to both figure it out and get the work done. I used Polar White for the low SRI (68) to keep the roof cooler - solar works better on a cool roof. I had the added benefit of being able to button up my last gable end by moonlight the night before my inspection. I couldn't see the ground but it was easy to see my roof and install the fasteners/trim. I ran lots of fasteners along the main standing seam panels. My biggest concern was the potential for high winds on solar panels/s-5! clips to peel the roof panels. I would prefer the solar panels to give way first. Pullout from the SIP skin is the limiting factor. I used Metal Sales Image II panels $4817 (included panels, trim, vent boot, butyl tape & caulk, etc.) Mid State High Temp Peel n Stick $1157 I bought the fasteners separately - Tek #10 pancake head screws (Tek product report 02704) There are many metal roof and peel and stick manufacturers that are similar. These were both readily available to me through a local supplier. The fasteners are less common.

Just checking in with an update, things are going well, stuff is getting fabricated... I was looking at wood-free rot-free subfloors and was wondering if anyone tried USG's cement-based panel? It's designed for steel floor joists (like mine) but targeted towards commercial construction (which is I guess is technically like mine, as well): https://www.usg.com/content/usgcom/en/products-solutions/products/structural/subfloor/usg-structural-panel-concrete-subfloor.html 5psf is a lot lighter than the 30psf poured concrete floor over fluted steel decking. Says it's rated to over 300 psf (!?) with sufficient joists, but I wonder if it can support vehicles even with that rating. Seems a shame to build an all-steel house and then build a subfloor out of plywood or OSB.

I remember it being very expensive, hard to obtain and had concerns that it would be hard to work with (plumbing penetrations etc.). That being said I can't find any price quote from when I looked at it. I ended up doing two offset layers of 3/4" T&G plywood.

Posted By greenbuilds on 19 Sep 2017 02:57 AM
Just checking in with an update, things are going well, stuff is getting fabricated... I was looking at wood-free rot-free subfloors and was wondering if anyone tried USG's cement-based panel? It's designed for steel floor joists (like mine) but targeted towards commercial construction (which is I guess is technically like mine, as well): https://www.usg.com/content/usgcom/en/products-solutions/products/structural/subfloor/usg-structural-panel-concrete-subfloor.html 5psf is a lot lighter than the 30psf poured concrete floor over fluted steel decking. Says it's rated to over 300 psf (!?) with sufficient joists, but I wonder if it can support vehicles even with that rating. Seems a shame to build an all-steel house and then build a subfloor out of plywood or OSB.

no it would not support vehicles
each tire print of my 1/2 ton pick up is approx one square foot and a concentrated load of 1,500 lbs
in addition an object in motion imposes a greater(and different dynamics) on a floor than a stationary load