Insulating and heating barn
We are are about to start on a project of converting our horse barn into an office area. We are in southern Coos County NH. The area we want to heat is 900 sf, so first floor only. Half the barn has a four foot crawlspace the other is full basement. The building is post and beam about 160 years old. The walls are 6 inches deep the floors and ceilings are thicker because of the beam construction. There is no natural gas, so propane Rinnai wall furnace is what we were considering for heat. Our plan was to use closed cell urethane for insulation, but are open to other ideas. The help we received on the house insulation worked beautifully this first winter. We thank you, the oilman not so much.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
I'm guessing from the fact that you are posting here that you care about environmental impact. If that's right, I'd stay away from spray foam. The blowing agent used to make the bubbles in it is a potent greenhouse gas, more than 1000X the effect of CO2. Normally, the global warming impact of the fuel use dwarfs the global warming impact of the building materials, but this is an exception.
Just this, year, a new "HFO" blowing agent has become commercially available in spray foam, with negligible global warming impact. You might be able to find someone who has access to that. The source I know of it Lapolla http://www.lapolla.com/foam-lok-2000-4g/ You can ask them to put in you touch with an contractor in your area.
But either way, spay foam is expensive. I'd be inclined to use cellulose, and if you want greater R-value than you'd get from 6" of it, make an inside non-structural wall spaced in from the existing wall by an inch or so, as the support for your interior wall board.
Ken,
By far the best way to insulate post-and-beam walls is with exterior rigid foam. You can also use SIPs or nailbase. (The reason is that the vertical posts interrupt insulation if you try to build stud walls between the posts, and any diagonal framing members just further complicate the air sealing and insulating details.)
If the office has a flat ceiling, you can't beat a deep layer of cellulose to insulate the ceiling.