So after we had consulted with solar-electric professionals as well as solar-electric DIYers, and realized that hiring the professionals would require three to four times what we have budgeted for a solar electric system, synchronicity prevailed. Thanks to some very fine friends, we were able to buy two brand new 205-watt, 12-volt photo voltaic panels with a 20-year guarantee well below cost, and they are now in our barn. It was nice to see the power of common interest and community at work! And I have to say that the pickup-bed to pickup-bed transfer at Great Maine Apple Day in the pouring rain lent a delightfully wicked blackmarket air to the transaction.
NOTE: This is what cordwood guru Rob Roy would deem the result of "cultivating coincidences," which you do by putting the word out that you need something. As Roy put it in his book, Timber Framing for the Rest of Us, "the more tentacles you send out into the world, the better the chances of latching onto something."
10/25/09
10/24/09
Remaining cordwood walls uncovered; temporary wall complete
How soon will we be able to move in to Sunnywood? That is the question. As the weather gets colder, the furnace in our rented mobile home runs more and more constantly. The structure doesn't breath, so even with all of the hot air from the forced-air furnace, moisture and mold build up and the air quality is really bad. Quite an incentive to move things along!
We removed the remaining tarps covering Sunnywood's cordwood walls, as they had been curing for the requisite month. Here is the north-facing wall. The only windows are the egress windows mandated by fire code.
The insulation that we've put in the temporary wall for winter will come in handy somewhere else when this wall comes down in the spring. You can also see the one-inch foam board insulation in the ceiling, which, in addition to the batting and wood above it, gives us about R-38 in the ceilings. Not quite the R-40 to -50 usually advised for passive solar, but close.
We removed the remaining tarps covering Sunnywood's cordwood walls, as they had been curing for the requisite month. Here is the north-facing wall. The only windows are the egress windows mandated by fire code.
Here are the east and south walls. The south wall has the most glazing of any wall, but is still insufficiently glazed for signficant solar gain.
Part of the balancing act we are struggling with concerns the small size of our house, and the fact that we need to maximize productive space. This means making use of wall space for things other than windows.
There remains the possibility that when we complete the last "wing" next year and fill in the last four cordwood panels, the remaining south-facing panel could be filled mostly with glass, making that corner of the greatroom a kind of sunspace. Proper placing of light-colored tile could act as thermal mass to moderate temperatures and reflect light and heat into the rest of the greatroom.
The temporary wall to close us in for winter is complete, except for the installation of the door. We were able to reuse the flakeboard that we'd used as a working surface over the floor joists while we built cordwood. When we build permanent interior walls, we will use wood planking instead, and put the flakeboard in service in an outbuilding, perhaps a wood shed.
The temporary wall to close us in for winter is complete, except for the installation of the door. We were able to reuse the flakeboard that we'd used as a working surface over the floor joists while we built cordwood. When we build permanent interior walls, we will use wood planking instead, and put the flakeboard in service in an outbuilding, perhaps a wood shed.
The insulation that we've put in the temporary wall for winter will come in handy somewhere else when this wall comes down in the spring. You can also see the one-inch foam board insulation in the ceiling, which, in addition to the batting and wood above it, gives us about R-38 in the ceilings. Not quite the R-40 to -50 usually advised for passive solar, but close.
10/12/09
We have heat!
The woodstoves are installed! This is the only work, besides the excavating for the foundation, that we have hired out. The installers from Rocky's (really---would I make that up?) did, in four hours, what would probably have taken us about three days, given our usual learning curve. Plus, their installation meets state fire codes, and if the roof leaks, we have people to blame it on. They were nice guys, even though they chipped our new tile. The markup on parts seemed a tad exhorbitant (but this is from the perspective of people who almost never hire out home improvement/construction work).
Joe had picked up a wood cookstove a year or so ago through an ad in Uncle Henry's. It was manufactured by Magee Furnace Company, which operated in Boston in the late 1800s. We sanded off some rust, applied furnace cement here and there, replaced a few stove bolts, and painted it. We fired it up today. The oven stays warm for a long time after the fire dies out.
Our big purchase, though, was a brand new Jotul woodstove. I have heated with wood for more than 20 years, but never with a new stove. We opted for a Black Bear 118, which looks small, but has an 8-hour burn and is rated for 1800 sq ft: more than double our area. It may well chase us out, but we were reluctant to go with the parlor-sized stove, as this is our only heat source.
So let's see: our windows are in, and we have heat. A temporary wall and a couple of doors are all that's standing in the way of getting out of our rented trailer. And interior walls.
After last night's HARD frost, we decided that it was time to disconnect the Bison hand pump from its outdoor setup and keep it safe and warm till we can install it next to our kitchen sink. Which will require the construction of counters. And plumbing. Pesky details.
10/11/09
Floor and hearth half done
We have more than half of the floor boards installed, and the hearth is complete (half a hearth in the photo below). We ended up using ceramic tile for the hearth, because it provided a lower profile than brick and seemed easier to keep clean. State fire codes mandated the use of cement board under the tile. All of the windows are installed (well, those in the finished cordwood walls, anyway). The wood cookstove and Jotul wood stove get installed tomorrow.
We have done pretty well, doing all of this work together, while living out of boxes in a rented trailer, only getting slightly annoyed with each other now and then. We were warned that cordwood (and other) building projects can take their toll on relationships, but for the most part the process has been surprisingly satisfying. Lately, we have discovered the art of parallel play. That is, projects that require two people, we do together. Projects that can be done by one person, we assign. So we've been laying floor boards together, because they're big and heavy and need one person compressing while another is securing--- but I built the hearth while Joe installed windows. Parallel play. :)
Regarding the photos below: if you remember, we built a rubble-trench foundation. Which means that the three courses of hemlock grade beams you see sit atop a well-tamped crushed-rock berm that fills a drained trench (which sits on ledge). Any water that finds its way to the grade beams (very little because of the site grading and the roof overhangs) drains away. On the outside, the grade beams are surrounded by an insulated apron (rigid foam at about 35 degrees) to keep the ground around the outside of the house warm and dry. Inside the grade beam, we put some foam and bubble-wrap barriers for a bit of extra protection from any drafts that might find their way through 18 inches of hemlock. We covered the ground under the house with gravel, to act as a capillary break for moisture. The floor joists are 16" on center, and we added mid-joist support in the form of bricks with shims, and large blocks where heavy items such as woodstoves and water tanks would be installed.
We have done pretty well, doing all of this work together, while living out of boxes in a rented trailer, only getting slightly annoyed with each other now and then. We were warned that cordwood (and other) building projects can take their toll on relationships, but for the most part the process has been surprisingly satisfying. Lately, we have discovered the art of parallel play. That is, projects that require two people, we do together. Projects that can be done by one person, we assign. So we've been laying floor boards together, because they're big and heavy and need one person compressing while another is securing--- but I built the hearth while Joe installed windows. Parallel play. :)
Regarding the photos below: if you remember, we built a rubble-trench foundation. Which means that the three courses of hemlock grade beams you see sit atop a well-tamped crushed-rock berm that fills a drained trench (which sits on ledge). Any water that finds its way to the grade beams (very little because of the site grading and the roof overhangs) drains away. On the outside, the grade beams are surrounded by an insulated apron (rigid foam at about 35 degrees) to keep the ground around the outside of the house warm and dry. Inside the grade beam, we put some foam and bubble-wrap barriers for a bit of extra protection from any drafts that might find their way through 18 inches of hemlock. We covered the ground under the house with gravel, to act as a capillary break for moisture. The floor joists are 16" on center, and we added mid-joist support in the form of bricks with shims, and large blocks where heavy items such as woodstoves and water tanks would be installed.
10/7/09
Passive-Solar, or Sun-Tempered?
One of our goals in building this house was to be able to live in something easy and inexpensive to heat---an important consideration in Maine. This naturally led us to try to incorporate passive-solar features.
The basic features of passive-solar house design include south-facing orientation, overhangs/shading, thermal mass, sufficient insulation, and energy-efficient windows. Now that the house is coming together, we can see that we have been more successful in incorporating some of these features than others.
We sited the house really well. To take advantage of the sun's heat, a house should be longer than wide, with the long axis east-west, and a long south-facing wall, fitted with lots of window glass situated to absorb the heat from the low winter sun.
Now that the windows are in, we think that we have under-glazed. Since the south wall fronts on a contiguous great-room space that is fairly shallow, we were afraid of overheating, so we were cautious about glazing. We also neglected to consider that the installed windows would actually lose a full two inches in each direction to the frame, so that the actual glass area is 4 inches narrower and 4 inches shorter than we had planned on each window.
On the other hand, we paid really close attention to the angle of the sun and where it hit the south wall in the winter and the summer, and put our glazing high enough to catch the winter sun and avoid most of the summer sun. Our 2.5-foot roof overhangs, also a key passive-solar feature, are integral to making this happen.
Regarding thermal mass: our external walls, with 18 inches of mortar and wood, supply a huge amount of ambient thermal mass. What we are missing is thermal mass specifically located to absorb and moderate the sun's rays. We can still add some in the future, but for now we have decided to forgo extra thermal mass in our internal walls and floors. (We had also decided against a concrete pad foundation, which is a feature of many passive-solar designs.)
Insulation: Our 18" walls contain an average of 8 inches of sawdust insulation. However the value of cordwood lies in the combination of insulation and thermal mass, even more so than in log homes. Nevertheless, I would guess that the insulation alone probably meets the standard for walls, even without considering the mass factor. Our ceiling has standard materials (batts and rigid foam) but at R35, is a somewhat lower R-value than the new super-efficient standards.
Energy-efficient windows: here's where we could have used a bit more education. We thought we had done well, and I was excited at the prospect of new, "Low-e" windows that reduce heat loss through the glass. However, we didn't realize that the windows that were sold to us as energy-efficient were actually "LoE-2" (the "2" is superscripted so you don't really notice it). LoE-2 windows, as it turns out, are manufactured and offered as the "standard" by the major window manufacturers as an attempt to meet the energy efficiency needs of all 50 states. In addition to reducing heat loss through the glass, they also limit solar heat gain by blocking passage of infrared and some ultraviolet rays---a feature helpful in hot-weather climates, but detrimental to a passive-solar design.
So, in the end, our house may end up functioning more as what Dan Chiras terms a "sun-tempered" design than a true passive-solar spacing-heating system. Even so, according to Chiras, a sun-tempered design can take care of 20 to 30 percent of the annual heating load. We'll report back after we've lived there for a while.
The basic features of passive-solar house design include south-facing orientation, overhangs/shading, thermal mass, sufficient insulation, and energy-efficient windows. Now that the house is coming together, we can see that we have been more successful in incorporating some of these features than others.
We sited the house really well. To take advantage of the sun's heat, a house should be longer than wide, with the long axis east-west, and a long south-facing wall, fitted with lots of window glass situated to absorb the heat from the low winter sun.
Now that the windows are in, we think that we have under-glazed. Since the south wall fronts on a contiguous great-room space that is fairly shallow, we were afraid of overheating, so we were cautious about glazing. We also neglected to consider that the installed windows would actually lose a full two inches in each direction to the frame, so that the actual glass area is 4 inches narrower and 4 inches shorter than we had planned on each window.
On the other hand, we paid really close attention to the angle of the sun and where it hit the south wall in the winter and the summer, and put our glazing high enough to catch the winter sun and avoid most of the summer sun. Our 2.5-foot roof overhangs, also a key passive-solar feature, are integral to making this happen.
Regarding thermal mass: our external walls, with 18 inches of mortar and wood, supply a huge amount of ambient thermal mass. What we are missing is thermal mass specifically located to absorb and moderate the sun's rays. We can still add some in the future, but for now we have decided to forgo extra thermal mass in our internal walls and floors. (We had also decided against a concrete pad foundation, which is a feature of many passive-solar designs.)
Insulation: Our 18" walls contain an average of 8 inches of sawdust insulation. However the value of cordwood lies in the combination of insulation and thermal mass, even more so than in log homes. Nevertheless, I would guess that the insulation alone probably meets the standard for walls, even without considering the mass factor. Our ceiling has standard materials (batts and rigid foam) but at R35, is a somewhat lower R-value than the new super-efficient standards.
Energy-efficient windows: here's where we could have used a bit more education. We thought we had done well, and I was excited at the prospect of new, "Low-e" windows that reduce heat loss through the glass. However, we didn't realize that the windows that were sold to us as energy-efficient were actually "LoE-2" (the "2" is superscripted so you don't really notice it). LoE-2 windows, as it turns out, are manufactured and offered as the "standard" by the major window manufacturers as an attempt to meet the energy efficiency needs of all 50 states. In addition to reducing heat loss through the glass, they also limit solar heat gain by blocking passage of infrared and some ultraviolet rays---a feature helpful in hot-weather climates, but detrimental to a passive-solar design.
So, in the end, our house may end up functioning more as what Dan Chiras terms a "sun-tempered" design than a true passive-solar spacing-heating system. Even so, according to Chiras, a sun-tempered design can take care of 20 to 30 percent of the annual heating load. We'll report back after we've lived there for a while.
10/4/09
Cordwood Commentary
It's worth remembering some of the comments people have made about our cordwood house, while helping us build, seeing finished walls, or watching us work:
"This is . . . different . . . "
"This is awesome!"
"Looks awfully tedious." (our neighbor)
"Won't it shift?"
"Won't it heave?"
"How do you keep the bugs out?"
"How long will something like this last?"
"So . . . you're not going to sheetrock inside?"
"You guys are out of your minds!"
"Pretty zen."
"This is really laborious."
"This is crazy!"
"Looks awfully tedious." (our neighbor again)
"This is so cool!"
"I'm happy for you guys, but I'm not really diggin this cordwood thing."
"It's like a fortess!"
"Me, I like to throw up some plywood, some vinyl, and call it good."
"You'll be able to heat it with a candle."
"Looks awfully tedious.' (neighbor---still)
"When I look at that wall, I think of 101 Dalmatians."
And the best one: "I'd say it looks pretty Zombie-proof."
"This is . . . different . . . "
"This is awesome!"
"Looks awfully tedious." (our neighbor)
"Won't it shift?"
"Won't it heave?"
"How do you keep the bugs out?"
"How long will something like this last?"
"So . . . you're not going to sheetrock inside?"
"You guys are out of your minds!"
"Pretty zen."
"This is really laborious."
"This is crazy!"
"Looks awfully tedious." (our neighbor again)
"This is so cool!"
"I'm happy for you guys, but I'm not really diggin this cordwood thing."
"It's like a fortess!"
"Me, I like to throw up some plywood, some vinyl, and call it good."
"You'll be able to heat it with a candle."
"Looks awfully tedious.' (neighbor---still)
"When I look at that wall, I think of 101 Dalmatians."
And the best one: "I'd say it looks pretty Zombie-proof."
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