[Greenbuilding] embodied energy was Polyiso strength on roof (ErgoDesk)

Fri Dec 12 09:23:05 CST 2014

That's a good point, Alan. I saw my first engineered SIPS (structural
insulated panel) house about 20 years ago in Vermont. We were installing a
masonry heater into it. It was basically a timber frame house, but without
the timber frame. It turns out that the SIPS panels used to close in a
timber frame house are all you need as a structure. Particularly impressive
was the roof, which was installed in a few hours with a crane - the T&G
pine panelling on the ceiling and outside soffits was already on. I've been
a big fan of SIPS myself over the years, experimenting with various
homebrew versions and ending up with 1/8" of home-made thinset plaster +
glass mesh as the exterior tension skin and finish. The strength to weight
ratio, and the rigidity you get from a lightweight box beam are awesome. If
you wanted something you could helicopter in, Buckminster Fuller style,
this would be the way to go.............Norbert

On Fri, Dec 12, 2014 at 9:09 AM, Alan Abrams <alan at abramsdesignbuild.com>
wrote:
>
> not to muddy these already murky waters, but there are at least two other
> factors that come into play.
>
> One is the method of installation. Consider exterior sidewall insulation:
> A 4' x 8' panel of foam is a versatile, modular size, which can be handled
> by a carpenter on the inevitable make-shift scaffold, with relative safety.
> It can cover at least 32 SF and be temporarily secured with two nails, for
> example, while furring strips are prepared. It would take four pieces of
> Roxul to cover the same area, and more fidgeting where substrates are not
> modular. It would require more fasteners--each nail or screw with its own
> EE, and each a thermal bridge. Exterior cellulose insulation (like some
> Passive House approaches) requires an entire framing system to support it.
>
> Another factor is permeability. This sword cuts the other way, because an
> assembly that must dry in both directions (for whatever climate related
> reason) favors both mineral fiber and cellulose. I'm not convinced that EPS
> has sufficient permeability to ignore its use on what ought to be a
> bi-directional breathing wall. Its use could therefore necessitate
> mechanical dehumidification in a moderate climate that wouldn't otherwise
> need AC.
>
> In the case of insulating an existing slab--which John Salmen has
> discussed at length in the past--EPS is a winner on both accounts: not only
> can it be fastened without screws or nails, but it is also where you would
> want a vapor barrier.
>
> In summary, it is not enough to consider these materials in the
> abstract--they also must be evaluated in their context.
>
> AA
>
> Alan Abrams
>
> *certified professional building designer, AIBDcertified passive house
> consultant, PHIUS*
> *certified passive house builder, PHIUS*
> cell     202-437-8583
> alan at abramsdesignbuild.com
> HELICON WORKS *Achitecture and Education*
> <http://www.heliconworks.com/index2.html>
>
> On Fri, Dec 12, 2014 at 8:18 AM, John Straube <jfstraube at uwaterloo.ca>
> wrote:
>>
>> I think the supply chain issue Alan and John are discussing is very valid
>> and does indeed show how complex it is to make the “best” decision
>> But John, you have some facts wildly wrong. That about 1 pound of EPS can
>> do 1 sq ft to R40 is correct although most people us Canadian Type 2, which
>> is a higher density and R4 per inch. A rounding error.
>>
>> But that high density stone wool is made by adding glue is not true. A 2
>> pound per cubic foot batt is definitely 95% or more stone, and the higher
>> density products like 4 pcf wall insulation or 8 pcf roof insulation have
>> MUCH more stone and may have a lower % of glue.  You could go to  factory
>> and watch the stream of fibers on the conveyor belt being squished to
>> different densities. The primary difference IS the amount of fibers in the
>> product.
>> Also, you have a Roxul stone wool plant in Maple Ridge BC  — which is not
>> 3000 km from where you are, it is very likely closer than the styrene plant
>> in Alberta.  It is true that the amount of rock wool you have to ship for
>> R40 is a LOT more, more than double (e.g., 3.3 pounds per square foot if
>> you did it all exterior, I would use 2 pcf batt in the cavity to roughly
>> get the first R20 and then 5” of pcf on the exterior for the next R20, so
>> lets say 2.6 pounds per square foot versus 1 pounds per square foot)
>>
>> The claim that 0.067 pounds of styrene makes 67 pounds of EPS is also
>> incorrect. Norbert is correct. It is true that a 1 pound sample of EPS may
>> contain only 0.1% of styrene monomer: this is one of the concerns with
>> styrofoam to some (not me) because the monomer can move and potentially
>> have health effects. It is often higher than 0.1% which is the problem.
>> But the remainder of that sample is polystyrene, the polymer. Pentane is
>> mostly removed at the factor during expansion and moulding, and replaced
>> with air which weighs about 0.075 pounds per cubic foot. So of the 1.2 pcf
>> for EPS, 1.1+ is polystyrene.  To make polystyrene you react the styrene
>> monomer to polymerize it.  So a pound of EPS in typical foam board is over
>> 95% from styrene monomer.  Not 1%. The steam is used to expand the beads
>> and mold them, it is not part of the chemical reaction and does not become
>> part of the product.
>>
>> How to compare the impact of 1 pound of styrene produced 1000 km away and
>> 2.6 pounds of stone melted 400 km away and 3.5 pounds of cellulose with
>> 0.5pound of borate?  I dont know.  This is tough.  Except for Ergo who
>> knows the answer before the analysis begins: EPS is always best.
>>
>> John
>>
>>
>> On Dec 11, 2014, at 11:38 PM, John Salmen <terrain at shaw.ca> wrote:
>>
>> > Actually it is something to be considered.
>> >
>> > The EPS product I use is manufactured from polystyrene beads which
>> combine styrene (0.1% by weight of finished product) and pentane (1% by
>> weight of finished product). These beads representing 1.1% of the final
>> product are manufactured in Alberta (about 1000 km from me). They are
>> shipped to Vancouver (about 130 km from me) where they are manufactured
>> into board stock using steam (local water and heat) and packaged into
>> roughly 96 cu.ft. polyethylene wrapped bundles (88 sq.ft. of 2ml poly).
>> >
>> > Each bundle weighs about 67 lbs with .067 lbs (about 1 ounce) of
>> styrene monomer and would insulate 64 sq. ft. of wall to roughly R40.  20
>> bundles could do the walls of a 1600 sq.ft. house – about 20 oz of styrene
>> (equivalent to 10 milk jugs when they were made of styrene)
>> >
>> > So basically I had about 6.7 lbs of polystyrene beads shipped 1000km
>> then converted into 67 lbs of finished insulation wrapped in 88 sq.ft of
>> poly ( and shipped 130km where it gets put into buildings and hopefully
>> subsequently taken out in board form and put into other buildings or
>> whatever things get recycled into in the future – probably milk jugs).
>> >
>> > I’m not sure I can do better than that at this point with less impact
>> for a local solution that works well in my climate –
>> >
>> > Straw would have to be shipped an equivalent distance (we have no local
>> wheat) – ironically it would take about 20 bales (about 900 lbs) to
>> insulate an equivalent area which takes about a ½ acre of farmland to grow
>> and about .1 lb (1.6oz) of petroleum derived fertilizer to generate the
>> growth.  Straw does not work in my climate.
>> >
>> > For cellulose the equivalent wall area or insulated area would be about
>> 200 lbs of shredded newspaper – so I could collect and shred papers locally
>> but I would still have to ship in 60 lbs or so of borates to make up that
>> amount at at least 4  times the distance. Also we are getting more
>> information that borates might not be as safe as we thought – not a well
>> investigated material. Also I have spent a lot of time politically working
>> on having newspaper recycled as pulp mills are a huge environmental
>> liability in my region as is deforestation.
>> >
>> > For rockwool for walls the equivalent wall area would be about 162 lb
>> and I would have to ship that about 3000 km (so double the weight and 3
>> times the distance – and 4 times the packaging). If I wanted to use a
>> rockwool as a board material comparable to the eps for slabs the equivalent
>> area weight would be about 800lbs (additional weight being formaldehyde
>> binder for density).
>> >
>> > So it is a complex decision making process. All design decisions are.
>> Is 1oz of styrene as dangerous as 60 lbs of borate salt, chlorine pollution
>> and tree loss, or potentially 600 lbs of formaldehyde glue,  or even the
>> soil loss and petro fertilizer usage from something as green as strawbales.
>> I don’t know and getting information to know a little more is a continuous
>> process -  but am certainly not at this point going to accept simple
>> arguments for simple materials having discovered long ago there is no such
>> thing as a simple material. Some of the most ‘natural’ materials out there
>> are still the most toxic and/or inappropriate.
>> >
>> >
>>
>>
>> John F Straube
>> jfstraube at uwaterloo.ca
>> www.JohnStraube.com
>>
>>
>>
>>
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-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com
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