Insulating a CMU frost wall - OT for alt.solar.thermal


Recently built a framed and truss shop building in Ohio. Will not be fully heated full-time, but want to maintain just above freezing, so it will be insulated.
There are concrete footers below frost line, and 8"CMU frost wall to above grade. The site slopes both directions, resulting in the uphill sides having a frost wall that is approx. 3-1/2' above the floor slab on the inside of the shop. The CMU is waterproofed and parged above grade.
The roof has had baffles and stuffed batt installed at the eaves prior to the drywall going up, to allow blown-in in the ceiling, and the walls will be done with dense pack cellulose ( blown in behind reinforced poly stapled to the 2x6 studs then drywall).
What I'm trying to decided is what's the best approach for insulating the frost wall on the inside. Can't fill the CMU's since there are too many that were grouted for strength to prevent the hill from pushing the wall in. And the building is already backfilled and graded so insulating the outside is not an option.
There is a small step where the wall sole plate / treated sill plate sit on the CMU. The options I've thought of so far are:
1. Build a "stud wall" out of treated 2x2, anchoring a sole to the slab, putting 2x2 "studs" 48"O.C., and a 2x4 top plate ripped to fit against the shop wall's sill plate. I'd cut 1-1/2" DOW stryrofoam to fit in between the "studs", and top with fire-taped drywall. This would let there be a mechanical attachment for the drywall.
2. Glue 1-1/2 or 2" DOW foam right to the CMU then adhere drywall to it, taping the seams with fiberglass mesh tape. Might use the ripped 2x at the top, nailed to the sole to reinforce the step that would result. Not sure if adhesives are up to the task?
3. "stud wall" as in 1, but using poly vapor barrier over batts. This is probably least attractive due to possible moisture infiltration into the batt from block side.
4. ?????????
Anyone have thoughts, observations, experience, or a suggestion for #4? Thanks in advance!
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If your goal is just to keep it above freezing, you may not have to do much if anything more other than the insualtion you have already in the walls and ceilings.
I have a 30x60 ft steel building, with insulation (fiberglass). Two insulated 10x16 ft doors, some (reasonably good) windows.
I run a small 1500 watt electric heater full time, and that keeps the temp above 32 except for the very coldest times--and even if the temp drops below freezing on a really cold day, nothing inside freezes.
(when I do work, I use a 200,000 BTU gas heater, which brings the temp inside up to 55 degrees in about 15 to 20 minutes--I do use a ceiling fan to move the air around, as I found that witout the fan, when it was 55 at the floor level, it was close to 80 at the ceiling!)
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Well, that was huge mistake. It's trivial to do it right when the hole is open. And the way to do it right, now, is to open the hole back up and insulate the outside down to the footing (and out from the footing a foot or two). In the lifespan of the building it's probably worth doing it right, now - MHO.
You could modify your option 2 and use concrete screws (blue things, no anchor required, if they work right) for some mechanical attachment through the drywall and foam, though the better quality adhesives are pretty good - it's just hard to say in the long term.
--
Cats, coffee, chocolate...vices to live by

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on 9/20/2009 4:14 PM (ET) v8z wrote the following:

4. Skylight(s) to let in the sun during the day?. They don't have to be high end, just the plastic bubble skylights(s). They may also supply some light. Windows on the sunny side to let in more sun, and light? Both the above won't help at night, but you may not have to run a heater as much, or not at all, during the sunny days.

--

Bill
In Hamptonburgh, NY
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on 9/21/2009 3:31 PM (ET) willshak wrote the following:

One more thing. A black roof.
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Bill
In Hamptonburgh, NY
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Thanks for the suggestions - shop does have 4 good quality windows on the long south wall, a couple on the east and none on the north or west. Has a dark roof too. As time and budget allow, I'll consider adding solar thermal collectors, but for now I've pretty much spent what I can....
....The house is a passive solar design, with r50 roof, r38 SIP first floor, and r28 ICF basement. Overhangs and shade roof designed to shade windows in summer, south half of house has a stepped down sub-floor to accomodate 1-7/8" of gycrete with tile over it for the main floor thermal mass, and the walk-out basement has good underslab insulation. All energy star appliances and every light and lamp is either CFL or T5. Energy star 5+ / HERS score of 50! Electrical was setup to easily accept PV when it drops in price, and next spring we plan to add solar thermal for dhw if budget allows.
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