“Decisions about insulation are among the most important you will make relative to the environmental impact of buildings. Because insulation reduces energy consumption, it provides environmental benefits throughout a building's life. More energy can be saved by conservation than by improving the efficiency of heating systems.”Henri Fennell
The insulation of the building was one of the most complex decisions of this building process.The more research we did, the more we realized the trade offs, the conflicting opinions and research- or lack of it.The old Ben Franklin decision tree on this one was more akin to a sophisticated decision matrix with extensive long and short term risk reward consequences.
First we need to reiterate our goals as it pertains not just to insulation but, as we learned, the whole building envelop.The order of these goals is not necessarily in order of their importance.
(1)Environmentally friendly manufacturing process for insulation (including embodied energy of the manufacturing process)
(2)Indoor air quality (limit gassing of insulation or other effects on air quality)
(3)Insulation value (we are trying to limit our energy consumption so retaining warmth in winter and cool in summer is a critical component).This is usually measured in R-value or aged R-value.
(4)Toxic Mold, the “new” environmental threat of the construction field.
(5)Durability, we are trying to have as many components in the building last for 200 years, the insulation is not an easily replaceable building component if it fails before our 200 year building life.
(6)Proven technology, time, science and lawsuits are three of the tests of a technology, aka- asbestos, pressure treated wood, CFC’s.Being on the cutting edge of a technology has its benefits so long as the sword can be removed without fatal consequences to the whole building in case the technology fails.
(7)Resistance to deteriation from insects, mice, bats, other critters, wind, ice, age and others.This building is in the middle of the woods and the critters are able to infestate virtually any crack in a building’s envelop.We are also in northern New England so weather is harsh.
(8)Air sealing ability.High R-ratings do little good if the total open spaces between the insulation add up to be the size of an open window.
(9)Healthy recycled product- being a recycled product does not mean it is a healthy product, if it had toxic material in its original form we need to know how much toxic material is in its recycled form.
(10)Local product and local company to support it.
(11)Construction site waste
(12)Long term maintenance
(13)Replace ability if life span is less than 200 years.
(14)References; history is a good measurement tool.
(15)Quality in manufacturing and craftsmanship.
(16)Return on Investment
Bottom line, more of the verifiable green stuff and less of the brown stuff.Seeing through this fog is important.Spending thirty years in the computer field we have lots of experience with vapor ware, smoke and mirrors, bugs and bubbles so we have fine tuned our antenna for b.s.
As with any decision we were bound by available knowledge, our own resources and time to make a decision.This was an area that would have been very easy to get stuck in the Buriden’s Ass dilemma. (From an old fable of an ass placed between two equally nice bales of hay. The ass couldn't decide which bale to turn to so it starved to death from indecision.)There were trade offs, values weighed, points made but no absolute winning technology that made this choice easy.With our goals and criteria detailed above and the trust that was earned by our Building Envelop Consultant Henri Fennell, we chose to use a field applied polyurethane foam spray for our wall building insulation.This work was done by a local company, FOAM-TECH, from Thetford Vermont.The walls have 4 ½ inches of polyurethane foam spray insulation for an R-31 value. The roof is a combination of products with a total of 8 inches of insulation for an R-50 value.We used off site manufactured stress skin panels with polyisocyanurate insulation with a Grace Ice and Water Shield vapor barrier.
FOAM-TECH has a division of their company called Building Envelop Solutions who came out and tested the building envelop and supervised the insulation until it reached the criteria they were comfortable with.These guys will be out again to do additional tests during the winter but the tests they did in the summer were cool.
Blower Door Test:Essentially all of the doors and windows in the building were shut and they covered one door with a plastic cover and a large fan and then proceeded to suck out as much air out of the building as they could.Well, okay, not all of it but the concept was to measure the pressure of the building inside versus outside and see how much air came back into the building and over what period of time the air pressure equalized.They did a bunch of calculations based on the Mechanical Engineers specification of what we wanted to accomplish with the building and gave us the results.WE FAILED MISERABLY.Ouch. How could all of our planning and all of the experts we hired not have ensured that we would pass this test with flying colors?!?!?Based on their calculations, they were able to tell us how large in total the holes were in our building envelop.Even though we could not see any holes, the combined total was like having a window open all of the time!!Onto the next test to find out what was going on.
Fog Test:In this test, we closed all of the doors and windows and they filled the house up with smoke (Fog). One individual stayed inside the building with a fog gun directing a concentrated amount of smoke towards certain parts of the walls and roofing.As this was going on inside a bunch of us were running around outside watching were the smoke was coming out of the building.As the picture below will show it was quite clear were the main problem was.Now the question was why and how to fix it.Well, apparently where the roof met the walls a channel was created and this channel was leaking air inside the building.The insulation guys from FOAM-TECH basically filled the channel with insulation and then spent a number of days foaming and retesting until they got the major issues taken care of.Now the square inches of air coming into the building were reduced substantially but not good enough for these obsessive compulsive guys from Building Envelop Solutions and not to the desired level that our Mechanical Engineers had specked out.Currently they estimate that there are about ten inches of open space in the building envelop, which for a 3400 square foot building does not seem bad to me but we have an idea where a lot of them are and the next time these guys come out and do the blower door test anyone left inside the building is going to pass out from lack of oxygen.
Infrared Thermography Test:This winter the guys from Building Envelop Solutions will be back out to the Barn House to do this test and essentially should be able to tell where heat is coming out of the building.