Neal Lewis Posted August 22, 2011 Report Posted August 22, 2011 This is new construction. There is R 38 Insulation between the 2x12 rafters, insulation baffles, ridge and soffit vents. There is no insulation in the ceilings/walls adjacent to the attic. There is a Cat IV furnace in the attic. Why would someone insulate this way, and how the heck does the building dept approve this?? I searched and couldn't find the most recent discussion on this. Click to Enlarge 40.15 KB
Marc Posted August 22, 2011 Report Posted August 22, 2011 Is the ventilation air provided by the soffit vents, baffles and ridge vents confined to the underside of the roof deck or does it flow through the attic? Marc
Nolan Kienitz Posted August 22, 2011 Report Posted August 22, 2011 Cheap version of "foam" insulation by not doing "foam" [?]
Neal Lewis Posted August 22, 2011 Author Report Posted August 22, 2011 Marc, the venting is strictly behind the insulation. Nolan, my first thought.
Neal Lewis Posted August 22, 2011 Author Report Posted August 22, 2011 So the exposed Kraft paper is OK?
kurt Posted August 22, 2011 Report Posted August 22, 2011 Oh, that part. Nope. Says so right on the wrapper.
hausdok Posted August 22, 2011 Report Posted August 22, 2011 Five years from now the kraft paper backing will be covered with drip stains and the underside of the roof will be nice and damp and might even be punky to boot. Can't install that insulation like that. They could have gotten away with unfaced batts but then they'd have to worry about them falling down. ONE TEAM - ONE FIGHT!!! Mike
Darren Posted August 22, 2011 Report Posted August 22, 2011 Hey Neal; Ask the builder or the Sub code official for the energy certificate. What town?
Chad Fabry Posted August 22, 2011 Report Posted August 22, 2011 If the baffles completely isolate the insulation from the deck, and if the baffles are perforated to allow vapor to pass to the ventilated cavity, and if the insulation meets the depth requirement, it meets the energy code. Except for the exposed kraft, how is the installation any different from a cathedral ceiling?
Neal Lewis Posted August 22, 2011 Author Report Posted August 22, 2011 The venting seemed to be in order, although I'm not sure about the perforated baffles. Darren, it was Montclair.
allseason Posted August 22, 2011 Report Posted August 22, 2011 Could be new thinking on the building envelope. It may be more beneficial to include the attic in the conditioned space to avoid the problems associated with them, one being a heat source in the attic. If the exposed paper is a problem it could be covered to improve the fire rating. This is likely the shape of things to come. GAF (I think) has developed a roof panel system that does the same thing. This thinking is also being applied to crawlspaces.
John Kogel Posted August 22, 2011 Report Posted August 22, 2011 Could be new thinking on the building envelope. It may be more beneficial to include the attic in the conditioned space to avoid the problems associated with them, one being a heat source in the attic. Agreed. The question now is what to use to cover that insulation. It's a bit too late to be hauling wallboard up there, eh? The insulation contractor screwed up, IMO. Unless the Authority is packing a ladder around with him, he didn't see it.
kurt Posted August 22, 2011 Report Posted August 22, 2011 I've seen it work "just fine" all the time in my neck of the woods. I'd never do it. As far as the exposed Kraft paper, my professional opinion is cover it. My personal opinion is it's an insignificant concern.
Neal Lewis Posted August 22, 2011 Author Report Posted August 22, 2011 This is a walk-in attic, new construction. Easy access. I didn't talk to the local town building dept, but the state building dept guy I just spoke with confirms to cover it. Dont know how the town approved it.
Rocon Posted August 22, 2011 Report Posted August 22, 2011 This is fairly common with a particular builder in Las Vegas. Click to Enlarge 52.05 KB Click to Enlarge 45.66 KB
John Kogel Posted August 22, 2011 Report Posted August 22, 2011 This is fairly common with a particular builder in Las Vegas. It's a crap shooter's house so staple up plastic and shoot it full of crap. []
John Kogel Posted August 22, 2011 Report Posted August 22, 2011 This is a walk-in attic, new construction. Easy access. I didn't talk to the local town building dept, but the state building dept guy I just spoke with confirms to cover it. Dont know how the town approved it. Cover it with drywall? Or some kind of new foam board?
Tom Raymond Posted August 22, 2011 Report Posted August 22, 2011 A walk up with easy access and nothing on the floor? I'd be more worried about that the kraft paper.
Bill Kibbel Posted August 22, 2011 Report Posted August 22, 2011 This will be more common now that wet sprinkler systems are going into single-family homes.
hausdok Posted August 22, 2011 Report Posted August 22, 2011 If the baffles completely isolate the insulation from the deck, and if the baffles are perforated to allow vapor to pass to the ventilated cavity, and if the insulation meets the depth requirement, it meets the energy code. Except for the exposed kraft, how is the installation any different from a cathedral ceiling? It needs to be covered and it's not going to stay. Sooner or later, gravity will take over - sooner if there is even one tiny mouse somewhere in that attic. Drywall does, to a certain degree inhibit the movement of moisture through a ceiling plane. probably even more so in your area, no? Don't thay use plastic behind drywall where you are on the warm side of the wall cavity to minimize vapor diffusion into cathedral ceilings? Around here they don't use any plastic barrier. When there's a layer of wood or drywall beneath the insulation and adequate ventilation it seems to work but when there's just the insulation it always seems to be screwed up. ONE TEAM - ONE FIGHT!!! Mike
Neal Lewis Posted August 23, 2011 Author Report Posted August 23, 2011 Mike, the only plastic behind drywall here would be sometimes at basement walls.
hausdok Posted August 23, 2011 Report Posted August 23, 2011 Sorry, I thought that had become standard practice back east in states where snow falls. ONE TEAM - ONE FIGHT!!! Mike
Mark P Posted August 23, 2011 Report Posted August 23, 2011 This is fairly common with a particular builder in Las Vegas. Click to Enlarge 52.05 KB Click to Enlarge 45.66 KB What is that orange pipe - CPVC? I've never seen orange before, any significance.
kurt Posted August 23, 2011 Report Posted August 23, 2011 It's residential fire suppression supply pipe.
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