Cathedral ceiling- cellulose vs spray foam?

[drz1050]

Thanks fellas! I'm definitely doing closed cell on the roof sheathing and basement sills, still undecided about cellulose or open cell for the walls. Leaning towards open cell now, as it's much less expensive. That's gone in the face of what I read before, but while the raw materials for cellulose are cheaper, the labor is far more.

 

[St. Coemgen]

Has anyone here gone the cathedral/ non-vented route? If so, what did you do?

I have an attic space, cathedral, as described but, it is vented with vented tile, and with fiberglass insulation (R35). We also have a plastic sheet (which was cheap) and a reflective heat layer (not cheap) between the insulation and the drywall, both acting as a moisture barrier and the reflective foil adds an additional "effective" R values. It is enough and works fine.

Just be aware, if you have a wood stove, a lot of the interior house air (and water in your air) will go up the chimney anyway, not through the insulation. The perfect and totally sealed house is only for those that have non-wood stoves. Fires need air. And wood heaters need some external air flow, which should be ideally fed with air from outside via a heat exchanger, but will always include some internal air. If you do not have an eternal air source for your stove, just leave one window a bit ajar. Trust me, it will not affect your insulation factors if you used at least one normal vapor barrier before adding the drywall.

And fresh air is good. We live in a volcanic region and radon gas is a potential issue. So circulating the internal air is just good practice.

I have hydrometers throughout the house. The house air moisture is highest in the summer when we are not using the stoves. And when I see the air moisture go up, I just open some windows, and that "solves" the problem in the summer.

 

[iamlucky13]

Stove ventilation is really a distinct matter from roof ventilation, as the former affects the conditioned air in your house, while the latter ideally does not. The best option for supplying air to a stove is arguably an outside air kit. Barring that, a combustion air vent in the room the stove is installed with a damper to prevent backflow of warm air to the outside when the stove is not in use is more controlled than just opening a window.