[Greenbuilding] Best bang for the buck in wall insulation

[Tom Lent]

According to the manufacturer disclosure in Pharos, Roxul Comfort Batt does
use a urea phenol formaldehyde binder so there can be formaldehyde
emissions. The product has been tested by Greenguard and received its Gold
certification so the emissions are relatively low, but still could be a
trigger to some with significant pre-existing sensitivity. Although many of
the major fiberglass batt manufacturers have gone to formaldehyde free
binders, I haven't yet seen a glass fiber board product (fiberglass or
mineral fiber) that is formaldehyde free.
http://www.pharosproject.net/product_category/show/id/1 
I'm really looking forward to Ecovative's board insulation product 
http://www.pharosproject.net/blog/detail/id/178/growing-the-built-environmen
t

- Tom
____________________________________
Tom Lent - Policy Director - Healthy Building Network
2464 West St, Berkeley, CA 94702    510-845-5600
www.healthybuilding.net www.pharosproject.net www.hpdcollaborative.org
@HBNTom

-----Original Message-----
From: Greenbuilding [mailto:greenbuilding-bounces at lists.bioenergylists.org]
On Behalf Of Frank Tettemer
Sent: Tuesday, March 25, 2014 4:33 PM
To: Greenbuilding at bioenergylists.org
Subject: Re: [Greenbuilding] Best bang for the buck in wall insulation

Adding to to Jason and RT's information, and the description of Roxul and
it's use, I would add that Roxul has all those good qualities that they've
mentioned, but is entirely dependent upon the skills of the installers to be
a good fit.
The Roxul Comfort Batts, made for the interstices between 2x4 studs, can be
accurately sliced off using a sharrpened, long bread-knife, and if the cuts
are square and accurate, the resulting piece will fill and seal the wall
cavity quite well.
If not cut square and accurately, the result is worse than the use of
fiberglass batts, which will "stretch" a bit to fix a poor cut and measure.
Roxul does not "stretch". It crumbles.
Good carpenters are required, so that good results can be expected.

The Roxul Comfort Board, made to be applied outside of the studs, also
requires care, as it too can degrade with poor installation techniques.
I love the stuff, but it takes a lot of thickness to add up to R-50 or so in
the wall system.

Side issue: Each person is different, and I know two different people who
can not tolerate being around the application of the Roxul Batts. 
Dust is not the issue, but some sort of chemical intolerance is the issue.
Perhaps the batts are formed using formaldehyde as the stiffener? 
At any rate, there is a fume to be concerned about, for some people.

Perhaps with 2x6 framing, and R-22 batts, layered over the exterior, with
two layers of 1 1/2" Comfort Board, at R-6 per 1 1/2" layer, we get a total
of R-28. If we add another 1 1/2" Comfort Board on the inside of the wall
frame, and strap it with 1x4 furring strips, as a substrate for dry wall or
plaster lathe, we still only have a total of R-34 or less for the wall
system.  R-34 is not enough for your purposes.
............................................................................
......
Deva Racusin, from Vermont, has built some beautiful straw bale combined
with Roxul Drainboard, and dense-packed cellulose to achieve R-60 overall,
which is a happy combination, too. I co-wrote a presentation, Building For A
Cold Climate, with him a few years ago, and his system looks good. See this
wall system in his book, "The Natural Building Companion".
............................................................................
......
But if straw bales are too intimidating, then double-stud framed with dense
packed cellulose is the very best possibility to achieve R-60.

I'm with Topher.
Without hesitation.
My favorite choice has been 2x4 frame loadbearing wall. Quick. Easy. 
Minimizes lumber use. Strong enough and meets code.
See the attached photo.
Describing the layers in this system:
 From the outside moving towards the inside:
~ Vertical wood board siding, (vertical provides good drainage) something
like board and batten, or, Fraser Board Contour Siding, or hardee board; ~
horizontal 1x4 furring strips@ 16" o.c., as substrate for vertical siding; ~
attached to studs with #8 x 4" yellow zinc screws, ~ through 1 1/2" Roxul
Comfort Board, ~ over 1/2" poplar plywood as a wall sheathing, (Pure Bond
Ply, with no formaldehyde glues), ~ into 2"x4"@ 24" o.c. load-bearing studs,
~ with a similar 2"x3" @ 24" o.c. non-load-bearing studs framed parallel to
the outer wall frame, on the interior, ~ and spaced a full 14" inside of the
outer plywood sheathing. Allows 14" of dense packed cellulose, @ R-45

This inner frame will be covered with MemBrain, by CertainTeed, variably
permeable membrane vapour retarder, stapled to 2x3 studs, and covered over
with 2"x2" horizontal furring strips @ 16" o.c., as a substrate for drywall,
or, plaster lathe.

After strapping over the membrane, the dense pack process can begin, through
the membrane, and it is easy to visually see how well each cavity is filled
under 3lbs+ pressure.
Total R-Value of the system is R-52. or R-60 @ 18" of cellulose with half
inch plywood and 1 1/2" Roxul Comfort Board exterior.

The electrical wires and boxes can all be fastened to the 2x2 strips, and
wires run through the 2x2's, with no puncturing of the vapour membrane at
all, and no need for fussy "booties" around each electrical box, and still
achieve 1 1/4" set-back for safety behind the plastered or dry-walled wall
surface.
For maximum thermal mass, inside this very warm wall system, 5/8" 
drywall or, 1" plaster works just great to slow the diurnal temperature
swings, when using firewood and solar gain as heating fuels.
Total wall thickness still adds up to similar to a well-built straw bale
wall system, but R-value is higher.
Embodied energy is also higher, but most all materials in the system are
benign to the environment, expecially using earthen plasters on the
interior, (except the MemBrain ... hard to get around using plastech! as a
vapour barrier, with most wall systems).

Hope this helps, Lynnelle. (More choices? Oh no!)

Frank Tettemer
Living Sol ~ Building and Design
www.livingsol.com
613 756 3884



On Tue, 25 Mar 2014 15:56:08 -0400, Jason Holstine <jason at amicusgreen.com>
wrote:

>
> Roxul ... doesn¹t burn (made of recycled steel and volcanic rock), 
> deals with vapor and water nicely,

>  Only downside is availability in your area may still be dicey.


I understand that economy of words is a good thing but in Jason's case, a
few more wouldn't have hurt.

As far as I'm aware, Roxul is not made of recycled steel.

For the last 30-odd years I've been under the impression that the materials
used to make Roxul are basalt and slag (a by-product from the blast furnace
cycle of iron or steel production). Some of you may remember seeing chunks
of the stuff when you were a kid, playing where you weren't supposed to be
playing, alongside railroad tracks.

Roxul may still be relatively new to Murricans but it's been widely
available in all building supply outlets since at least the early 1980s if
not 1970s, in batts and rigid boards.

The Roxul area rep would often set up a table in the local building supply
store and entertain passersby with his demonstrations of Roxul's fire
resistance (destroying other insulations with a propane torch while
gleefully achieving nothing with the same torch held onto a piece of
Roxul) ... Roxul's ability to repel and float on water (even after being
held underwater for an extended period of time and Roxul's ability to drain
itself dry after water was forced into it under pressure.

Best of all, it doesn't make you itch all over or make you spit up blood
when installing the stuff, like fibreglass does (makes me cringe just
thinking about that F-G-ing stuff). Slightly better R-value than the same
thickness of F-G too.

Guess I went a bit overboard with the words when all I really wanted to say
was "Not recycled steel".

--
=== * ===
Rob Tom                    AOD257
Kanata, Ontario, Canada

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