I felt fortunate in that we had some decent weather today, and I was able to make a good dent in adding insulation under the solar shed.
Colleen did a great job designing and doing the initial shed construction, heavily insulating the floor as she went and crafting the whole thing with 4x4s for strength. I took over after that (while she did important stuff in the house proper) to install the walls and then insulate both the walls and the ceiling. We did pretty good and the shed has worked well for the more moderate winter temps (say, mid-20s), soaking up heat from the sun during the day and then staying warm overnight with a couple of space heaters running off internal outlets.
With the recent cold snap I realized that there were still some gaps in the insulation sheath though--standing in the shed I could feel cold drafts coming from plywood joints in the floor and (of course) under the not-quite-square door. While I haven't yet figured out what I want to do about the door (besides packing it along the bottom with towels and such to cut the draft) I could fairly easily address the floor issue by adding more insulation.
The problem is fundamentally the way the shed sits. It's primarily off the ground on footings, since the slope is approximately 25o, and since we were in a hurry we didn't feel we could take the time to excavate it all out to make a flat spot. While we set the footings very solidly into the ground using a combination of concrete pads and poured concrete, the large gap means that the underside of the shed is exposed to the cold air--and that's undoubtedly been causing a lot of our heat loss.
So I spent today working on the shed instead of on the house proper, cutting and wedging in some of the same rigid blue Styrofoam insulation that I'd used for Tanglewood's underslab insulation. This stuff is very effective, providing an R-10 insulation value in only 2" of space and being relatively easy to work with since it's rigid--I just stuck it up there and tacked up a couple of nails to hold it in place. The hardest part was cutting the foam to fit, since the 4x4 joists under the shed are (to put it kindly) not precisely square themselves.
Over the course of the afternoon I got half of the underside insulated, leaving only the outer edge (which will be the easiest to work on) and the inner edge (which is up against the hill and where I only have about 6" to work in). I think for the upper edge I'll just wedge in a big piece of the more conventional fiberglass batt insulation, while on the outer edge I'll use more of the rigid foam, but will have to do more cutting, since that's where the main electrical conduits come in from the house run and the solar panels. Once all of the insulation is in place, I'll use some of the handy dandy spray foam to seal the gaps, and then close the whole thing up with plywood sheathing to help keep the critters out. Once that is all done, I plan to further insulate by dropping the exterior siding down to just above the ground to help keep the wind from whistling through, though that might be a project for springtime if the snow doesn't melt!
It might have been my imagination, but I thought the shed was a bit warmer than it "had been" before I left this evening. Of course I was hot from working and cutting and nailing and whatnot, so I'll rely on my temperature readings tomorrow as a more accurate gauge.
Back at the house I hooked up the 100-pound tank that I'd brought up since we discovered that we'd run the 500-gallon tank down yesterday and got it feeding the house. We had to cycle the boiler a couple of times to get it to light--the error code translated to "tried to ignite five times" (why do these manufacturers insist on having weird 4-digit error codes that you have to translate, by the way?). I figure that meant that there was air in the line, not surprising since we ran the large tank out in the first place.
Now, a 100-pound propane tank only holds about 23.6 gallons of gas, so I don't expect this to last more than a week or so depending on how much the house calls for (the slab is below temp right now, so it might well suck it all up running the radiant full time), but we'll see how it goes. Of course as I noted earlier, this is purely a temporary measure, keeping the house warm and making things bearable for our overnight and multi-day stays. It'll be very nice to get my full 2,000 gallons in place later this summer!
Again not many Punch List items got done, since I was working on the shed, though I did haul out another couple bags of construction trash (there's a lot of it).
I'm still astonished by how long it takes to work "just a couple of things"... wow...
Steven in Colorado Springs
My Construction Website
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|At mid-morning, the system was pulling in about 2.8 kWh while the batteries were well on their way to full charge.||
|By the end of my sunlight window, the system was generating only a little power (415 watts); the battery voltage was down slightly because of my power tool usage.|