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<div class="moz-cite-prefix">Kim,<br>
<br>
We've worked with air source heat pumps a bit; while they will
certainly help with drying in regards to adding heat to the
building, the turbulence is designed to be low for comfort
reasons, and I don't think you can bank on that being any more of
a drying strategy than any other (vented) space heater (assuming
you are describing a ductless ASHP, and not a full-house ducted
system). Great donation, though, super heaters!<br>
<br>
Let us know what you find with wool, I'd be excited to see what
the college comes up with. Could be good precedent - we've got a
lot of extra wool in VT...<br>
<br>
Thanks for the link to the CHMC report, I'd heard tell and seen
some abbreviated results but not the full report, I look forward
to checking it out. Good clarification on your vernacular design
spec's, makes sense - we take a similar approach in VT, cladding
is great if it works with the design and/or the mirco-climate
dictates, but not a requirement. Of course, we don't carry the
burden of a marine climate ;)<br>
<br>
Keep us posted, best of luck!<br>
<br>
Jacob<br>
<pre class="moz-signature" cols="72">Jacob Deva Racusin
New Frameworks Natural Building, LLC
P.O. Box 15, Montgomery, VT 05470
(802) 782-7783 (c)
(802) 326-2209 (h)
<a class="moz-txt-link-abbreviated" href="http://www.newframeworks.com">www.newframeworks.com</a>
<a class="moz-txt-link-abbreviated" href="mailto:jacob@newframeworks.com">jacob@newframeworks.com</a></pre>
On 4/30/2013 7:18 AM, kim thompson wrote:<br>
</div>
<blockquote
cite="mid:11B490EB-D140-438D-B946-A81C58B9917A@ns.sympatico.ca"
type="cite">
<div>First .... to all who have worked so hard on SB code issues
over the years - thank you for your dedication and passion.</div>
<div>There is a resounding ring of hope circling the globe as
Martin's latest news spreads and congratulations roll in. So
inspiring.</div>
<div>-------------------------------------------------------</div>
Hi Jacob,
<div><br>
</div>
<div>Thank you for your thoughtful comments on my question about
insulation/air barrier options for the Morris.</div>
<div>I will share them with committee members and let you know
what transpires.</div>
<div><br>
</div>
<div>Regarding access to the wall cavities - removal of damaged
plaster and inserting holes</div>
<div>as needed to pack cellulose (or other insulation) have been
discussed. Your mention of</div>
<div>drying time for straw clay are well taken - this is certainly
an issue in our climate. We have had an</div>
<div>air source heat pump donated to the project which could, we
conjecture, (this is new technology to me)</div>
<div> contribute to accelerated drying of whatever materials we
use.</div>
<div><br>
</div>
<div>Am continuing to work on the wool insulation option - the
local agricultural college is doing experiments in this area and</div>
<div>we hope to use some of their products this year. They are
using success of wool batt and blown in, in UK and NZ for their
marketing plans.</div>
<div><br>
</div>
<div>All the best,</div>
<div><br>
</div>
<div>kim</div>
<div><br>
</div>
<div>BTW I do indeed know Annie M, Nova Scotia is small! Just had
a view of her starring role in S*** </div>
<div><br>
</div>
<div>Also you may be interested in having a look at a report I did
a few years ago for CMHC looking at best practices and
challenges for </div>
<div>building with straw bales in Atlantic Canada. While wood
cladding and/or other rain screens are being used on many
projects, I wouldn't say</div>
<div>they are the norm. Adding this extra skin is generally
recommended on a case by case basis - it is especially effective
where a building is exposed to </div>
<div>our driving horizontal rains, however for material
conservation and aesthetic it is often not specified. Verandas
and generous overhangs are often used as well.</div>
<div><br>
</div>
<div>Report can be ordered for free from Tel. 1 800 668-2642. Be
sure to ask for the full report </div>
<div>which includes a 20 min dvd of interviews with bale builders
and a data base of the of 40+ buildings profiled.</div>
<div>Straw Bale Construction in Atlantic Canada</div>
<div>HIghlights and Full Report #65828</div>
<div>Order desk: <a moz-do-not-send="true"
href="https://www03.cmhc-schl.gc.ca/b2c/b2c/init.do?language=en">https://www03.cmhc-schl.gc.ca/b2c/b2c/init.do?language=en</a>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
<div>
<div>On 2013-04-28, at 11:55 PM, Jacob Deva Racusin wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<div text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">Kim,<br>
<br>
Wow, what a great project! That's a really dramatic
image of the Morris House next to the massive
glass-faced skyscraper...good on ya!<br>
<br>
I'm a bit hesitant to reply given the tremendous wealth
of knowledge on this list, but it's a great question so
I'll take a crack. My understanding of 'nogging' is
brick non-structural cavity infill, yes? And you are
looking to insulate the empty cavity sections above the
brick?<br>
<br>
The concern about creating a moisture problem by
introducing insulation is a valid one - there is plenty
of precedence for this unfortunate dynamic. The
introduction of insulation reduces the drying potential
of the assembly, and can create condensation problems
which did not previously exist. Insulation can be
introduced safely, however, if moisture sources are
considered and mitigation strategies are designed into
the work. First and foremost, keeping bulk liquid
moisture out of the assembly is critical (wind-driven
rain and window leaks are two notorious and insidious
examples). That's the most significant source of
moisture damage, and even a small window leak that might
have previously gone undetected can become a bigger
problem when heat loss from inside the building is shut
off and drying potential is reduced. The next step
involves air-sealing, which you reference would be part
of the protocol. This is critical to reduce
bulk-loading of moisture vapor into the wall through air
leakage. When I do building performance work, I see
plenty of examples of weatherization work done in the
80s, when insulation was added in attics without air
sealing, and it is not uncommon to see evidence of
moisture damage in particularly leaking locations. I'm
unclear as to how you would be accessing the interior of
the cavity and addressing air leakage, but this would be
an important move prior to/in concert with insulating (I
note that none of the insulation materials you reference
are air barriers themselves, requiring a separate air
sealing approach). In your climate, air-sealing from
the interior - stopping the moisture drive at its source
- is desirable, although a primary air barrier on the
exterior can work well too if the detailing is tight and
the air barrier is vapor permeable enough to allow
drying to the exterior as need be. You mention that
there is no vapor barrier in the wall assembly; myself,
I prefer such vapor-open strategies, but it is very
important that these be deployed with rock-solid water
control and air-tightness measures to be effective.
Diffusion through materials alone is very unlikely to
cause a problem, but can push conditions in a wall or
ceiling into a danger zone if there are other moisture
issues also at play. <br>
<br>
I like dense-pack cellulose because it has a relatively
high R-value compared to other in-fill insulation, is
fire-retardant without the use of HFRCs, performs a
notable amount of air circulation retardation (not an
air barrier, but does slow movement down a good bit),
has a high hydroscopicity that allows concentrations of
moisture to disperse throughout the material (avoiding
higher concentrations in specific areas) and dry out if
given the opportunity, is pretty ecologically-benign and
not too industrially-intensive (depending on the
specific product), and installs dry - a big plus
compared to many of the wet-wall natural building
materials I otherwise favor using. I am unfamiliar with
aerogel in practice, only in theory, so I won't comment,
but my bigger concern around straw-clay and hempcrete
would be the amount of built-in moisture you are
introducing into the cavity. Provided you can ensure
adequate drying within a reasonable amount of time they
could work fine if you are alright using a relatively
lower-R material, but since moisture is a chief concern
of your committee that might be a harder sell. We don't
have much access to affordable wool insulation, but that
could be an attractive option - again, providing
thorough air sealing measures are taken, as it will be
unlikely to stop air flow to any appreciable degree. I
like the idea of the reused brick - the lowest
insulative value of any on your list, but I like the nod
to finishing the original design, for whatever that's
worth (perhaps not much, if your goal is to maximize
comfort for the inhabitants).<br>
<br>
I hope that helps. There are some great case studies on
both <a moz-do-not-send="true"
href="http://GreenBuildingAdvisor.com">GreenBuildingAdvisor.com</a>
and <a moz-do-not-send="true"
href="http://BuildingScience.com">BuildingScience.com</a>
that provide some good examples of similar situations, I
can dig up some examples off-list if you have trouble
finding them. Best of luck, keep up the good work!<br>
<br>
Jacob<br>
<pre class="moz-signature" cols="72">Jacob Deva Racusin
New Frameworks Natural Building, LLC
P.O. Box 15, Montgomery, VT 05470
(802) 782-7783 (c)
(802) 326-2209 (h)
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="http://www.newframeworks.com/">www.newframeworks.com</a>
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:jacob@newframeworks.com">jacob@newframeworks.com</a></pre>
On 4/26/2013 12:50 AM, kim thompson wrote:<br>
</div>
<blockquote
cite="mid:5187D3E6-3008-47AD-8A09-AD6B99A9BEF2@ns.sympatico.ca"
type="cite">
<div>Hello all,</div>
<div><br>
</div>
<div>I have had a note in progress for GSBN'ers for
weeks to ask a question related to Jacob's.</div>
<div>A building I am currently involved with was built
in 1764. We recently moved the 2.5 storey home </div>
<div>nearly 5 km through central Halifax to a lot where
it will be rehabilitated and used for affordable
housing for youth.</div>
<div><br>
</div>
<div><a moz-do-not-send="true"
href="http://morrishouse.ca/">The Morris House</a> has
become an interesting demo of how we can make heritage
buildings more energy efficient (and</div>
<div>keep them out of the land fill). It has a number of
unusual (for Halifax) features including solid brick
nogging which fills the cavities in the</div>
<div>first and half way up the second floor levels of
the Georgian timber frame. There has been considerable
discussion amoung committee members</div>
<div>involved with the Project about whether or not
to fill in the currently uninsulated wall sections,
and if so with what. Heritage folks want to employ </div>
<div>minimal intervention strategies and add nothing -
they are concerned that introducing insulation will
bring with it moisture which will </div>
<div>compromise the timber frame.</div>
<div><br>
</div>
<div>I have proposed a few options and would so
appreciate thoughts from this group on the building
science side of things for</div>
<div>our northern maritime climate. Thermal comfort
(cold walls especially) will be important to the young
people living there, as will be </div>
<div>heating costs... construction materials and systems
on this project will certainly be cited as
recommendations for future heritage rehabs. </div>
<div><br>
</div>
<div>So my question is what might be the pros and cons
of insulating the currently empty wall cavities above
the nogging with one of the following:</div>
<div>(a) dense pack cellulose (b) light straw clay (c)
hempcrete (d) reuse of brick from the chimneys of the
Morris. (e) blown in or batt wool (f) aerogel.</div>
<div>Assuming any one of these would be installed with
great care to avoid air leakage. </div>
<div>Exterior cladding is painted cedar shake, interior
is lime plaster/lathe, no vapourbarriers and removal
of the nogging is not an option.</div>
<div>Are there other choices apart from providing "extra
sweaters" for the tenants that would not compromise
of the structure.</div>
<div><br>
</div>
<div>Am hoping that John S. in particular might chime in
on this.</div>
<div><br>
</div>
<div>Thank you all!</div>
<div><br>
</div>
<div>Kim Thompson</div>
<div><a moz-do-not-send="true"
href="http://www.themorrisproject.ca/">www.themorrisproject.ca</a></div>
<div><br>
</div>
<br>
<div>
<div>On 2013-04-25, at 11:46 PM, Jacob Deva Racusin
wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div>Hello,<br>
<br>
My apologies for the cross-post, but I'm trying to
do a very quick and broad survey.<br>
<br>
I was just contacted by a former student I am
advising, who is project managing a building
currently in design phase, in the mid-Atlantic
region in the eastern US. The wall assembly was
initially to be straw-clay, with plaster finish on
both sides. Budget and logistics have directed an
insulation switch to cellulose. He is currently
advocating for wood lath with lime-stabilized
earthen base coat, with finish lime coat (our
standard approach for finish exterior plaster).
The architect is balking, suggesting that the
moisture storage and release dynamics for which we
rely upon the plaster in straw-based designs will
not play out the same way with cellulose, that the
cellulose will be overwhelmed with moisture and
push the dew point deep into the wall. This is
all second-hand reporting of the conversation - I
know no more than what I just reported - but I am
due to speak with the architect and client
tomorrow on my student's behalf, and I'm curious
as to whether or not any of you have direct
experience with earth base plaster over wood lath
outboard of a dense-packed cellulose-insulate
wall, or any reason to believe the cellulose would
not behave adequately in concert with adjoining
plaster (as opposed to straw).<br>
<br>
The architect is spec'ing (outward from the
framing) plywood, housewrap, drainage gap, stucco
lathe, plaster. My impression is that this
suggestion would certainly work, but is hardly the
natural wall system initially intended. It seems
to be playing off of the concerns of sun-powered
vapor drive pushing vapor deep into the wall
cavity as a result of a reservoir cladding
adjoining the insulation. As long as there is no
interior vapor barrier or Class II vapor retarder,
I feel this dynamic is identical to that we've
created with straw-insulated walls, and if
anything the cellulose would stand up better to
incidental vapor or liquid moisture intrusion.
Also note generous overhangs and 24" grade
separation are spec'd in the design, as is
multiple coats of limewash (and potentially a
silicate top coat for durability), which will
further reduce bulk water absorption and minimize
incidental solar-powered vapor drive. The wall is
designed to dry to both sides of the assembly, in
keeping with the variable moisture drive of that
region.<br>
<br>
Perhaps there is another concern here I'm not
understanding - I'll find out more tomorrow - but
in the meantime if anyone has any perspective on
why this situation would work for straw, and not
cell, or any direct experience in a comparable
climate executing such a system, I'd be grateful
for your input.<br>
<br>
Thanks so much,<br>
Jacob<br>
<br>
-- <br>
Jacob Deva Racusin<br>
New Frameworks Natural Building, LLC<br>
P.O. Box 15, Montgomery, VT 05470<br>
(802) 782-7783 (c)<br>
(802) 326-2209 (h)<br>
<a moz-do-not-send="true"
href="http://www.newframeworks.com/">www.newframeworks.com</a><br>
<a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:jacob@newframeworks.com">jacob@newframeworks.com</a><br>
<br>
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