October 18, 2002
E.E. Foam Home
Before I get started discussing this week's foam installation, I thought it might be wise to reflect on what our intentions have been for this house since we started dreaming about it. Our intent has been to build the house as the last house we will ever live in. Not knowing what our financial future may bring as we grow older, the goal has been to build a house that is energy self-sufficient (as possible) and earth friendly. Quite a few decisions have been made that involve making investments that will payoff over the lifetime of the house. One example, the standing seam metal roof is by far, much more expensive, than a standard asphalt shingled roof, but this roof should last 75 years or more. Another reason why we went with the metal roof is that it provides for rain water collection and it is virtually fireproof.
You have probably also heard the term "overkill" mentioned in quite a few of the journal entries. For our climate a double-wall cordwood house is probably overkill, but if we can reduce our future energy needs by investing in today's dollars using my own labor, I'll take the blame for over-engineering the house.
So what is the advantage to a double-wall cordwood house? Having two independent cordwood walls allows the builder the luxury of reducing air infiltration to almost nil. Nothing negates the benefits of R-value more than air infiltration. Cliff Shockey realized this when he built his double-wall cordwood house in Saskatoon, Saskatchewan and rightfully so, his house won Harrowsmith's award for energy efficiency.
I have used a number of ideas from previous builders and a few ideas of my own during the construction of this house in hopes of achieving superior energy efficiency. One such idea has been the use of a spray foam in between the walls to nullify air infiltration and provide additional R-value to boot. This idea is an experiment of sorts. Foam insulation has been around for years, just like cordwood walls, but marrying the two of them has only been done once before as far as I know.
The March/April 1991 issue of Harrowsmith magazine featured an article about Jane Bexton's cordwood house near Guelph, Ontario. (This article will be published here on DayCreek in the coming months.) She built a single 16" thick cordwood wall and inserted plastic tubes in the mortar. Later, the tubes were used to blow foam insulation into the cavity between the beads of mortar. This approach seals up the wall cavity, but leaves the log ends susceptible to air infiltration. My approach is to take it one step further by building two independent walls using foam insulation in between the walls.
Using foam insulation is not the most earth-friendly method of insulating a home, but I believe the benefits of saving fuel energy outweigh any of it's negative attributes. I narrowed my search down to foam products that are considered "green" from a health hazard point of view. In other words, they do not out-gas any toxic chemicals. There are also new soy oil based foams that will probably make sense too, but at this point, there's not enough of a track record with these products to make me feel comfortable about their use.
Be aware though, that using foam insulation with cordwood walls is experimental. Cordwood walls are typically made to breath. This keeps the wood dry and free from rot. With that in mind, I narrowed my search down to only open-cell foam products. Open-cell foam will not trap moisture like close-cell foam. I feel this is very important in a cordwood wall to prevent any moisture from becoming trapped.
You probably have seen or used the close-cell type foam. This foam is urethane based and hard to the touch when dry. This product does out-gas. It's R-value per inch is greater than open-cell, but it can trap moisture reducing the R-value and potentially causing other nasty things like rotted wood.
The open-cell foam is water based and has the characteristics of a sponge or foam rubber. It's R-value isn't as great per inch, but the cost is similar to close-cell foam per R-value. It only out-gasses for a short period of time (days). And most importantly it will not trap moisture, allowing vapor to transpire through the foam.
|I'm not sure what Mark was thinking when he got around to the sunrise bottle wall, but it probably wasn't a nice thought. All of the bottle tubes were marked with sticks and whatever else would work so I could find them later on.|
I originally learned of open-cell foam from a neighbor who had Icynene sprayed on the brick interior of an old school house that he converted into a house. Once I learned about Icynene, I started checking out contractors in the area that installed the product. Thankfully, I was sitting down when I got my first price quote of $.33 per board foot. For a house with a wall area of 1,876 sq. ft., it would cost $3,095 for 5" (R19) of foam insulation. At that point, I wondered if there were any alternatives.
Doing some research on the Internet revealed another product made by Demilec called Sealection 500. The product was comparable to Icynene and even had an advantage that it sticks better to itself. This makes it easier to apply the foam in layers instead of spraying it on in one fell swoop. Another advantage was the price. At .25 per board foot, it was still quite expensive, but an easier pill to swallow. (.25 vs. 33 includes my labor for prepping the walls.)
No matter though, it does require a contractor to apply the foam and after experiencing the technique firsthand, I can certainly understand why a contractor needs to do the installation. There is a lot of expensive equipment required to apply the foam.
So I made the decision to go ahead with the Demilec spray foam product. I could have certainly used other forms of insulation to fill in the gap between the walls, but the foam insulation was the best option in my opinion. Stopping air infiltration in walls is a huge plus and applying the foam would allow me to keep the house warm this winter. Having the exterior wall completed, along with the foam, already provides for an R-28 wall, which is far superior to any R-19 standard insulated wall that typically has air infiltration problems.
Here's how this week went...
Monday was foam installation day and I awoke to freezing temperatures, but otherwise not too bad of a day. The temperature inside the house was a cool 42° F, but a thermometer sandwiched between the floor and a bag of insulation read 76°. (Oh how I yearn for the day that the heat stays in the house!)
Mark Malay, owner of Waterway Insulation was due to arrive at 9 a.m. and well...Mark is not your typical contractor. He showed up on time! As with any major undertaking there's always the trepidation that something will go wrong, but not in this case. It was by far one of the best experiences I have had with a contractor. Mark always returned my phone calls and made a couple of visits to the house ahead of the installation date to make sure everything happened without a hitch. It was a flawless installation and I can't say enough about Mark Malaya class act to be sure.
It took about an hour for the foam resin to reach proper temperature and by 10:30 a.m. we were foaming. The whole process is quite interesting. Just like an epoxy glue, the foam elements are not combined until sprayed from a special pressurized nozzle. As it is sprayed on, the materials interact to produce the foam. The foam does expand, but not as much as I thought it would. For sure the foam penetrates all cracks and crevices, but not enough that any of the foam was forced all the way through the wall to the exterior. (As to how many lady bugs met their demise, it's anyone's guess, but some future scientist will probably bring them back to life with their well preserved genes.)
By 12:30 p.m., Mark, along with assistance from Tom and myself were able to spray the majority of the second floor. (We started upstairs first.) It was then time for Mark to open a new barrel and get it to the proper temperature, so we took a lunch break. After lunch, things went as smoothly as the morning and by 5:30 p.m. the house walls were completely sealed with foam.
Now that the house walls were foamed, it was time to direct my attention back to the ceiling/attic space. If you recall, I have been slooowwwllllyyy paneling the ceiling space for the last millennium. But now, it was time to stop virtually all the air leaks in the house. I still had quite a bit of ceiling area that was not covered with a vapor retarder, so Tuesday was spent sealing up the ceiling with 6 mil plastic. By 7:30 in the evening the outdoor temperature was in the 30's while it was in the 60's in the house thanks to a warm soapstone fire and a sealed ceiling.
By Wednesday morning the outdoor temperature had dropped to 23°F. I had a hard time keeping my toes warm in my little cabin, but surprisingly the temperature in the house had only dropped to 54°F. With virtually no insulation in the ceiling, the vapor retarder was keeping quite a bit of heat in the house. Checking the floor thermometer sandwiched under the insulation, the temperature read 79°F. The last four days had been mostly sunny, and now the floor heat was doing its thing. It only took a one hour burn using the stove to get the temperatures into the upper 60's. I can't tell you what a great feeling it is to know that I can now keep the house comfortable without much effort. Between the solar heated floor and a small wood stove, it doesn't take much to get things warm! And the best part of all is that this was achieved without any attic insulation! I am amazed at what a difference the vapor retarder makes.
I spent the rest of the day installing the wood paneling and made a trip to Tri-County electric to purchase the backup electric boiler.
Thursday morning started with a few snowflakes in the air with temperatures in the mid 30's. After another cool night in the cabin, I walked to the house and opened the door to find the temperature still in the low 60's with the floor thermometer reading 81°F! I stoked the stove and within an hour the ladybugs were dancing on the ceiling.
I don't want to get too giddy at this point, but so far the house is operating as planned or better. The combination of the wall foam and vapor barrier has gotten me to the point where the house is now livable. There's still a lot of work that needs to be done before winter sets in, but there's light at the end of the proverbial tunnel.
Next week I should be wrapping up the ceiling paneling and the electric line is suppose to be trenched to the house on Friday. And sometime during the week of the 28th, the cellulose insulation should be installed. Then, the first week in November should find me busy installing the backup boiler. By mid November, the house should be quite livable and the plans are to continue working on the house through the winter months.
A special "Thank You" goes out to Tom who helped with the foam installation and took photographs of the special event.
By the way... E.E. Foam Home stands for Energy Efficient Foam Home.
|By Thursday afternoon, 8 of the 16 sided ceiling were completed. (The spot near the top center of the photograph is the electrical box for one of the ceiling fans.)|