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Ok, I have asked this on another board and seen great responce. On low Slope roofing you get to chose both the substrate, insulation and roof assembly to create the longest lasting roof you can, money not being the object. Design to your hearts content.
TH
 
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TomHay said:
Ok, I have asked this on another board and seen great responce. On low Slope roofing you get to chose both the substrate, insulation and roof assembly to create the longest lasting roof you can, money not being the object. Design to your hearts content.
TH

Tom, Just spray it with urethane and the roof will last forever [ if done right]
 

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Grumpy said:
What tells me that was tom posting as the unregistered? :)
Well, lets go this way. You have seen me post hundreds if not thousands of posts in the Roofers Coffee Shop. I always use my real name and am never shy. You might keep track right now however as the foam poster even though he did not give a full system description was the only reply. Mine would have been a full system from deck up and might or might not be foam as I am certified and do many systems as well as foam. (yes when I post it, it will be foam)
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pitch plan

Personally on a moderate to low pitched roof i would recomend standard timber 5x3" rafter section,a PuR insulation a timber substrate a vapour barrier fully bonded a cork insulation a traditional 3layer b u f r,finished with a copper surfaced capsheet(£175.00 per 8metre roll).very apleasing to the eye one would think and very durable!!
 

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The perfect roof.
Tie down: 2 1/2" threaded SS rods per truss end, welded to rebar and cast into tiebeam.
Trusses: 3" X 6" 6061T6 aluminum I beam, all welded construction, bolted on 16" cents.
Sheathing: Durashield fiberglass foam core panels, 3" x 24", R-21. Edge glued and through bolted to trusses, all SS fasteners.
Roof surface: 3 ply laminate of 20 oz. tooling fabric in Isophthalic resin. Topcoat with .125" gelcoat (color of choice).
Soffit: Durashield panels, 1" X 12", R-7. Edge glued and screwed to trusses and sealed with 3M 5200.
Gable ends: 3 X 24 Durashield bolted to trusses and sealed with 5200.
Interior: All area over soffits and seams at gable ends sealed with spray in polyurethane foam.
Ventilation: Conditioned space.

This is one expensive roof and may have to be re-gelcoated in about 150 yrs. but it's not going anywhere.
 

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If the pitch is 2/12 or better... two layers of 30 lb felt, and a Galvalume r-panel system in mill finish. Mill finish is like your basic black dress, it goes with everything. (smile)
 

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Grumpy,
I didn't understand Teetor much neither. I kinda get the balck dress thing though. Hmmm?!?!?
Just surveyed a copper standing seam last roof is the first roof circa 1919. Not bad, Huh?

--Bill
 

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I am expecting to see a revolution in roofing in the very near future. 80% of the major damage that occurred here was due to roof failure.
Oil is currently hoverering around $50 bucks a barrel and I don't see that going down ever. That relates directly to heating and cooling costs and roofing. R values are going to have to come up to provide more efficient homes. I believe that in the very near future the day of the OSB/felt/shingles will be history. Sprayed polyurethanes may pose a 'quick fix' for R-value but locking up wooden substructure has always proved to be bad form in the end.
 

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Metal roofing ontop of ridgid insulation should provide longevity, and is a reasonably good insulator. The problem with insulating your roof deck is you usually eliminate ventilation and that could be a problem. Your best bet is a well insulated attic floor and well ventilated attic space.

Most rigid insulations are oil based. All plastic and poly's come from oil (to the best of my knowledge). We may have to further experiment in bio oils like the soy bean. This would both be good for economy and enviroment.

If you have a flat roof then a concrete deck with a bio based sprayed foam would be great for both R value and longevity. Put a garden on that thing and you have more R value and useable space.

I agree with your statement Teetor. Infact the city of Chicago has considered, or maybe passed, a bill for tax incentives for building owners who use green roof products. That's part of the reason I registered www.chicagogreenroofs.com Nothing there yet but it's a coming trend I intend to capitalize on.
 

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Grumpy, most foams and many plastics/epoxies went water based about 10 yrs. ago. I don't recall the exact year but do remember the volume differences and two accidents involving burns. Polyurethane reactions produce relatively high temperatures, enough for second degree burns.
 

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I hear the water based foams are 5x the cost... that's just what I hear.The author of this thread knows more than I. I also hear that they are HIGHLY temprature sensative.

LOL I have heard sotries about liquid Poly's blowing up in trucks.
 

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Grumpy, At the time of the switch we experienced a higher volume of mixed material for the same volume of liquid material. Price stayed the same.
We were pouring into fixed molds and retaining pressure to ensure no voids or gaps in the finished product. Some bypass was expected and was minimal, the formula had been worked out to only a few cubic ins. surplus. When the switch was made to water based, two of the bypass valves could not handle the flow and blew the cover off of the sprue constituting the two injuries. I'll bet that the mess is still on the walls and ceiling.
 
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