Monopoly framing in CZ 5
I have read various articles on Monopoly framing, and really like the idea of making the attic a conditioned part of the home. This would allow the furnace and water heater to be placed in the attic (and make slab plumbing easier) to alleviate some floor space in some of the smaller homes I build (1,000 sq ft).
I am not sure where to get some solid answers on how to insulate the roof deck, and was hoping to get some direction on that. I like the idea of dense pack cellulose in the rafter cavities, but I believe there would be moisture issues. I have read that multiple inches of closed cell spray foam would be needed before adding the cellulose, and probably a vapor permeable membrane at the ridge.
I would gladly hire someone to help me design this so I get it right the first time, but I don’t know where to look for that either. I added a few attachments of the most recent plan I wanted to use it on, but ended up not doing so.
Thanks in advance for the advice!
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Replies
Warren,
You can insulate at the roof-line using any of the assemblies in this link:
https://www.greenbuildingadvisor.com/article/five-cathedral-ceilings-that-work
Monopoly framing makes sense only if you are doing no overhangs or building a timber frame with a T&G ceiling with an over-roof for insulation.
For a standard build with overhangs the benefits outweigh the complications.
Doesn't mean you can't build a conditioned attic, I would do it with scissor or parallel chord trusses with batts and an air barrier (taped membrane/OSB/CDX/faced foam) under them. If you plan ahead, you can extend this air barrier over your walls (ie strip of house wrap over the top plates before you set the trusses) and tape it to the sheathing for air barrier continuity.
The ceiling can than be over the air barrier for any cathedraled areas or dropped if you need to run ducting.
Since you have a low slope roof, it might make more sense to go for trusses with a duct chase than anything cathedraled. Still the same idea, insulated with fluffy and solid air barrier under the trusses.
You can also dense back this assembly but you need some vent baffles that will hold up to the pressure.