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GSBN: Digest for 5/19/05

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-> Re: GSBN:More moisture problems - Southern California
     by Paul Lacinski paul@...
-> Re: GSBN:More moisture problems - Southern California
     by jeff@...
-> RE: GSBN:More moisture problems - Southern California
     by "Huff'n'Puff" huffnpuff@...
-> Re: GSBN:More moisture problems - Southern California
     by "Bob Bolles" Bob@...
-> Re: GSBN:More moisture problems - Southern California
     by Rene Dalmeijer rene.dalmeijer@...
-> Re: GSBN:More moisture problems - Southern California
     by "Bob Bolles" Bob@...


Date: 19 May 2005 00:27:50 -0600
From: Paul Lacinski paul@...
Subject: Re: GSBN:More moisture problems - Southern California


We have been dealing with some moisture issues lately as well, which
are not as dramatic as yours, but are troubling nonetheless.  I'm
gathering data at the moment and will be writing to the list before
too long.  This is all a sign that straw bale construction is growing
up, though I agree that it's very hard for the people on whom the
problems land.

I don't have any documetable answers to any of your questions, but I
do have another question for you.  You said:
" +- 40% within the center of the bales. Other reading surrounding
the affected areas ranged between 15 and 20%. "  It would seem
important to look at the moisture levels at the interior and exterior
of the walls in these areas where the center was so wet.  Maybe you
have done this, but it's not clear from the language in your posting.
My experience has been that wetness from rain on the wall surface (or
even potential wetness from rain- in our climate it can be difficult
to separate rain from condensation as sources) does not penetrate
more than an inch or two into the bale.  It is difficult to imagine
rainwater making its way to the center of the bale wall, unless
through a leak.  And it's nearly impossible to imagine it making its
way to the interior.  It may be possible in the 15-20% regions to
document some pattern of striation through the wall section- is it
consistently wettest toward the interior, middle, or exterior?  In
any situation that is only an exaggeration of the normal conditions-
like lots of rain against the wall surface, instead of the normal
amounts, you would be able to pick out a pattern of dampness that was
an exaggeration of a normal pattern- wetter toward the outside, dryer
as you move in.  If this is not the case, it would seem that the
water is coming from somewhere else- like a roof leak.  This could be
useful in convincing the owner.

To get closer to an answer to your last question, while also giving
the owner something constructive to focus on,  I'm wondering whether
you can find an isolated section of wall on which to conduct an
accelerated drying experiment.  You could apply heat to the interior
face (maybe an electric blanket against the wall with a couple of
regular blankets behind it?) and then consistently test moisture
content from the outside.  If you cover your holes well (duct tape
seems to work) you should be able to re-use them without throwing off
your readings.  If you drill the holes a bit oversized, in successive
readings you can change the angle of the probe, to go into fresh
straw.  You might also put a thermometer behind the blanket at the
interior wall surface, and chart the temperature there. A max-min
thermometer could be helpful, though I would think the termperature
would remain pretty consistent.  Then a person who is adept with
these types of numbers might be able to extrapolate your readings to
guess at a drying rate under more normal temperatures.

Best of luck and please keep us updated on your progress.


>Good day all,
>Sorry for some cross-posting to a couple of other lists.
>Like the Straw Wolf and Danny Buck, we have a real problem with
>"moisture" in the walls of a project in our area. No, it isn't one
>of mine, but it is this kind of "problem" that can give Straw Bale
>Construction a bad name, so it is everyone's problem.
>I do remember the exchanges regarding the SB that Danny was working
>on, but was kicking myself because I hadn't saved them - Thank you
>Joyce for "reminding" me that it had been reprinted in issue #49 of
>TLS, and thank you all for your extremely valuable insight and
>sharing your experiences. If we can actually root out the sources of
>the moisture, and come to some conclusions, I hope to be able to
>write some sort of analysis and summary for future reference. I
>think your past and future input on the subject will be invaluable.
>This is a large home (3,000 Sf) with lots of amenities, and the
>parapet style is consistent with other projects by the same
>This year was one of those few "wet" years that we have, and in the
>area of the project, (Ramona, San Diego County, CA - USA) the
>rainfall for the season was ~25 inches; the 2nd highest on record.
>Some of the rains were very heavy downpours and much of those were
>wind-driven directly into the South and West-facing parapet walls.
>Several items of particular note: Water was detected dripping out of
>the kitchen soffit after only 1-1/2 days of rain, and moisture
>content readings, principally grouped in 6 different locations, were
>recorded at +- 40% within the center of the bales. Other reading
>surrounding the affected areas ranged between 15 and 20%. While the
>current readings indicate some areas were wetter than others, I
>believe (speculating) that the leakage occurred pretty much all
>along the parapet walls on the South and West sides of the house.
>There were wet walls elsewhere, but perhaps they were caused by
>different problems. The architect just reminded me that there were
>also quite a few wet spots in the wood-framed portions of the home,
>which makes this even more interesting.
>All window and door opening were sealed with bituminous material
>between the openings and the frames. I have been told that a
>moisture barrier was used to cover the wooden parapets and lapped
>over the bales.
>The plaster was a 3-coat cement stucco - I am still investigating
>whether lime was used in the mix, but it seems unlikely. It seems
>more probable that the plaster was more of a moisture barrier than a
>likely source as the point of water entry. No sealer was applied to
>the stucco. There is some cracking, both horizontal and vertical,
>and while a few are potentially large enough to allow water into the
>bale interior, at best they could only account for some of the water
>at some locations. There are also hairline cracks; and I guess the
>thinking is that the rainfall may have penetrated all 3 plaster
>The framing details on the plans don't really tell me a lot about
>the construction of the parapet, other than it seems to be an
>extensions of the posts, and I am assuming that it was sheathed,
>papered, lathed and plastered. The roofing detail sheet is a
>cookie-cutter and doesn't even illustrate a parapet of this type.
>I have compared notes with Mark Tighe, another experienced bale
>builder and who also examined the house - each of our independent
>investigations lasted about 3 hours. We both came to pretty much the
>same conclusion that nothing that we could see would account for all
>of the water that appears to have entered the wall up around the
>(wooden) parapet extension. There was at least some penetration
>there because there were consistent wet readings all along the top
>of the walls at the ceiling. We can't tell how much entered there or
>how much may have entered down the wall.
>It has been suggested that where the first water was spotted, one
>potential scenario is that water penetrated the stucco (from where
>is yet unknown) and ran down the inside face of the interior plaster
>until it hit the box beam kitchen soffit, where it poured into the
>soffit and out the light fixture. This might account for the kitchen
>leak, but in the few plastered test walls that I have (struggled to)
>removed the plaster from, there wasn't what you would call a lot of
>room for water to travel through very rapidly. Also, how would the
>water get to the interior plaster surface? Water doesn't flow very
>well across bales.
>To make this all a bit more interesting, the owner has grasped onto
>the idea of installing a sheet moisture barrier between the plaster
>and the bales when the time for repair comes (not that I blame him
>at this point). I and others (and he has read) have explained that
>this is likely to cause moisture to be trapped within the cavity and
>in itself cause rot. He said that he had heard that, but has yet to
>see evidence that is really true. Not that is shakes my faith in the
>truth of the supposition, come to think of it, other than from the
>Straw Wolf, neither have I, though John Straube has published some
>very convincing test data that certainly makes the case.
>My next step is to contact the contractor, that is now out of state,
>and see if they can give some insight as to the potential failures.
>I have requested that the owners create a grid of test holes from
>the inside, where the others are, and really see if we can figure
>out just where and how widespread the problem really is.
>I feel for these folks, fearing the worst (whatever that is) and
>about to watch parts of their house being demolished. Not happy
>campers and I know that everyone feels badly.
>I would appreciate hearing your thoughts on the subject.
>At the moment, the owners are pretty upset that they are in this
>position, and are now questioning anyone's point of view unless
>there is documented evidence to back the assertions up. I can't
>fault them for that.
>Their questions are as follows - please do what you can to provide
>some sort of documentation and/or experiences supporting your
>1) Do parapet walls "always" allow moisture penetration? Any
>experiences or testing that might indicate why some did and others
>2) Does 3-coat cement plaster (stucco) allow enough water to
>penetrate a wall and substantially "soak" the bales? I seem to
>recall that Dr. Straube's tests involved capillary uptake, but I
>don't think that if I had the rest results in front of me I would
>necessarily understand them without a really clear explanation. How
>would this compare to rainfall on a vertical wall surface?
>3) Will a sheet moisture barrier between the bales and the plaster
>cause the bales to decompose?
>4) Will a non permeable stucco function the same as a sheet moisture
>barrier and cause the bales to decompose?
>5) Is there any rule of thumb that would give us an indication that
>over that moisture content % the bales won't likely dry out, but
>under that % they will likely dry out. I understand that is a
>"difficult" question because much will depend on the drying
>conditions, but I was wondering if someone had reached some
>conclusion made from personal observation in their experiences.
>I will pass on any developments as I can.
>My thanks in advance for any insight, experiences, information on
>other failures and documentation of the causes. If at all possible,
>I am in hopes that we will be able to pass on any information that
>will assist those in the future make "better" and informed decisions.
>Bob Bolles
>Join our Community bulletin board
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- --
Paul M. Lacinski
GreenSpace Collaborative
Sidehill Farm
Mail: PO Box 107
Packages: 463 Main Street
Ashfield, MA 01330 USA
+1   413 628 3800

View excerpts from Serious Straw Bale at:
<a  target="_blank" href="http://www.chelseagreen.com/2004/items/seriousstrawbale";>http://www.chelseagreen.com/2004/items/seriousstrawbale</a>


Date: 19 May 2005 01:09:41 -0600
From: jeff@...
Subject: Re: GSBN:More moisture problems - Southern California


It seems as the years go by, we are all becoming quasi moisture experts.
  As time goes by, we are going to see more of this, and it makes you
wonder how long all of us will be in business if it becomes too
widespread.  As Paul put it, it is part of straw bale growing up.

I have inspected two bale buildings built with parapets that incurred
moisture damage.  The first was a visitor center for the Nature
Conservancy near Colorado Springs about 7 years ago.  Water was making
it's way into the walls where the parapets and roof overhang met.  The
roof sloped to the north where the parapet was absent, and overhung the
wall by about 12".  The flashing and roofing at this juncture were very
poor and we could see down into the wall.  These two locations were at
the north corners of the building (east and west ends of the north
wall).  The water would travel straight down and hit rebar staples used
at the corners during construction.  This caused the water to spread out
and damage a larger area.

There were cracks in the plaster on the parapets and a small (relatively
speaking when compared to other areas) amount of moisture was making
it's way into the walls.  However, it did not appear to be the major
source of damage that occurred.

There were other areas of damage particularly under windows.  Caulk was
not present and the windows were not flashed properly.  There were no
windows sills.

Remediation of these problems included ripping off areas of plaster and
removing the slimy bales.  They were replaced with new bales or cob and
re-plastered.  The roof details were repaired and everything caulked.  I
did not do this work, but observed it's progress a couple times.  The
cost of doing this work was on the order of $40,000.

The second project was more recent in Salida, Colorado.  David Eisenberg
and Laura Struempler also visited this project.  They may have
additional insight in addition to my comments here.  The parapets were
made of bales and everything was encased in wet applied foam over and
down to the bottom of the parapets.  Cement plaster was applied over the
parapets and down the wall.  Sod staples were used to attach the lath to
the parapets, through the foam, creating thousands of pathways for
moisture to migrate.  This seemed like the primary source of moisture.
The moisture rotted the bales everywhere and was working on the top
bales in the wall, below the parapet.  There was a significant amount of
moisture from these holes.  The foam trapped the moisture effectively
creating a mold experiment.  This owner ripped off all of the exterior
plaster and the bales on the entire structure after consulting with us.
  He framed a wall on the exterior sill plate and foamed against the
interior plaster which remained intact.  He then re-plastered the
sheathed framed the walls, still with parapets, but flashed better than
before.  He now has a framed house with parapets that are flashed and

The lessons learned from both of these projects are not as clear as they
may seem, but there are some to be learned, I think.

In the case of the Nature Conservancy building, they bit the bullet and
tore out the portions we tested as damaged.  The source of moisture was
clear both before and after the plaster was removed.  It appeared our
probing with a moisture meter was accurate enough to isolate the damaged

In the case of the Salida project, the damage was everywhere above the
roof deck, but not so apparent below.  The owner ripped out everything
just to make sure he did not have a bale house to sell in the future.

In both cases, IMHO, the type of plaster did not contribute to the
damage.  Both were cement plaster, but had it been earth or lime, the
same damage would have occurred because of the parapet details.  Whether
the damage could have been detected earlier with other plaster materials
is another question.

What I do know is that both builders thought they new what they were
doing at the time.  They made mistakes and did not seek out real
solutions to moisture control in buildings during the design process.
Both wanted to fix the problem and were convinced that they needed to
use solutions that would permanently fix the problem, as witnessed with
other systems like a sheet barrier.  However, without our help, the
problems would have continued because the systems they would have chosen
to "remedy" the problem would have been mis-applied.  The main lesson is
in the details!

The thought process that happens by lay-people during these times can be
wrought with emotion or clouded by partial information.  The owner of
the Salida house was explaining the problems by describing them as micro
and macro-climate scenarios within his walls.  He is a scientist by
profession and wanted to explain it in a precise way.  The fact was that
it was pretty simple and the remedy was to keep the water out that was
making it's way into the walls via the parapets.  Pretty simple, but it
took weeks to convince him that even though his micro/macro climate
scenarios may be valid to some extent, the solution was simple and
straightforward.  I had him flash the parapets to bring any water that
makes it through the plaster on the parapets back out.  This meant a
flashing line visible around the entire house at the base of the parapets.

A final chapter (and an aside to your concerns) to this saga was during
the ripping out of bales.  They were using power tools (circular saws
with abrasive blades) to cut sections of the exterior plaster before
ripping it off.  One day, sparks ignited the exposed straw in a high
wind and the house caught on fire while they were at lunch.  The fire
department came out and doused a corner of the house.  Talk about an
ongoing trauma/nightmare scenario!  The lessons from this is be careful
when doing remediation work.

Finally, I know that this may not offer you any solid answers to your
problems, but may help with detection of the extent of damage and how to
deal with it.  Sheet barriers would not help with either of these
scenarios.  Proper details are the most important issues when dealing
with long-term solutions.

In my opinion, we need to be proactive in discouraging flat-roof/parapet
designs for straw bale construction.  Bale walls are more susceptible to
moisture because they soak it up.  I agree with Paul's observation that
point source damage will not soak the entire bale wall unless there is a
course for the water to take that will lead it to the center of the
bales.  Moisture travels straight down, unless directed horizontally by
other means, such as a rebar staple.

Good luck in your investigation.  It will not be pretty!

Jeff Ruppert, P.E.

Odisea LLC
Ecological Building, Engineering and Consulting

Front Range Office 		West Slope Office
5444 Marshall Road		1022 Main St.
Boulder, CO  80305		Carbondale, CO 81623
303.443.4335			970.948.5744
303.443.4355 f			1.866.795.6699 f


Date: 19 May 2005 02:14:12 -0600
From: "Huff'n'Puff" huffnpuff@...
Subject: RE: GSBN:More moisture problems - Southern California

G 'day GSBN Balers
Wondered how long before we received more reports of this problem with
moisture and poor detailing and or design for straw bale.
Web learned the lesson many moons ago and I am on record at the ISBBC in
San Francisco about the two buildings we built without eaves and of my
fears back then of future problems that I expected with these two
buildings.  Both were cement rendered but the failures are confined to
around the window openings and it appears only in the two windows that
had no flashing or sills.  The other windows that are flashed and have
sills have stood up to the test of time now over 7 years.
The rainfall in this area is quite high some 36ion average although we
are now in a drought the worst in 100 years I still feel that they will
hold up with regular maintenance.  Even so I will never again be a party
to designing or building any straw bale building that does not have
adequate protection from eaves or best practice verandahs all round.
I was wondering if we could publish these latest problems on the other
straw bale discussion lists?  As some of you may be aware there are a
few straw bale houses being built or recently built that are designed in
this style call it Santa Fe if you like.
I know that the GSBN is partly there for the iexpertsi to discuss these
issues but at what stage can we open the discussion with  this new
information to the others and some of these others are pretty adamant
that these designs will experience no problems.
My concern is that we are not sharing this latest info for the benefit
of all who are or have built in this fashion and when it is all said and
done it is fashion.  This could lead to many more problem straw bale
houses in the not so distant future.
What is our role here?
Kind regards 
The Straw Wolf
<a  target="_blank" href="http://strawbale.archinet.com.au";>http://strawbale.archinet.com.au</a>
61 2 6927 6027

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Date: 19 May 2005 02:24:23 -0600
From: "Bob Bolles" Bob@...
Subject: Re: GSBN:More moisture problems - Southern California

Hi Paul,
Many thanks for your thoughts.
I have an excel sheet with the readings to date that give the readings at
two depths - 11" and 17" from the inside wall - no holes were drilled on the
exterior to date; The probe was only 18" long. Without those readings from
the exterior I have no idea what the moisture at the outer edge is.
I appreciate your observations, and I wish that I could have conducted some
tests as you and others have suggested, but apparently it is out of my
At the beginning of the week I received a report that a piece of plaster was
removed from the exterior, and the bales were "completely wet". Apparently,
a decision was reached by the owners and the Architect that they would
remove all of the plaster, and "let the bales dry". And "after they dry
out", because no documentation was produced to "prove" that the parapet was
at fault, and that a moisture barrier will cause condensation and rot the
bales, a moisture barrier will be installed, and a lime/cement/sand plaster
reapplied. I don't believe that there is any plan to roof the parapet wall
in any way.
So, I will continue to research for any documentation regarding parapet
walls and moisture barriers causing rotting. Without such "proof" they seem
determined to do it their own way.
Thanks to you all~

Bob Bolles
San Diego California

- ----- Original Message -----
From: "Paul Lacinski" paul@...
To: "GSBN" GSBN@...
Sent: Wednesday, May 18, 2005 10:36 PM
Subject: Re: GSBN:More moisture problems - Southern California

> Bob,
> We have been dealing with some moisture issues lately as well, which
> are not as dramatic as yours, but are troubling nonetheless.  I'm
> gathering data at the moment and will be writing to the list before
> too long.  This is all a sign that straw bale construction is growing
> up, though I agree that it's very hard for the people on whom the
> problems land.


Date: 19 May 2005 03:54:09 -0600
From: Rene Dalmeijer rene.dalmeijer@...
Subject: Re: GSBN:More moisture problems - Southern California


Not that I think it will help much but make sure they know they are
going against the combined wisdom of everyone on this list based on the
laws of physics field evidence and testing.

Besides do they have evidence that what they propose will work with SB?
Or is their evidence based on transposing a completely inappropriate
solution from a different wall system.

I am sure we can come up with evidence that a vapour barrier will not
On May 19, 2005, at 09:21, Bob Bolles wrote:

> a moisture barrier will be installed, and a lime/cement/sand plaster
> reapplied. I don't believe that there is any plan to roof the parapet
> wall
> in any way.
> So, I will continue to research for any documentation regarding parapet
> walls and moisture barriers causing rotting. Without such "proof" they
> seem
> determined to do it their own way.


Date: 19 May 2005 10:45:29 -0600
From: "Bob Bolles" Bob@...
Subject: Re: GSBN:More moisture problems - Southern California

Many thanks again, Jeff.
I'm pretty sick of this whole thing.
I think the poor clients are being "led astray" by other "professionals",
and are thus unimpressed by those in the Straw Bale community.

I don't know if the attached would be of any interest, but I think that you
would be able to interpret and analyze it better than I can. I also sent it
to Dr. John Moisture Straube <smiling>.

Frankly, if they do as they seem to have indicated - putting a moisture
barrier up - I firmly believe that they are setting themselves up for
another failure, and giving all of us the black eye.

The architect is still convinced that there is nothing wrong with the
parapet concept.

I think I give up on it and need to put my energies somewhere it will do
some good.
I have put all of the feedback, including Danny's discussion, into a 52 page
file and am about to send it to them.

Thanks again, my friend - I hope our paths cross again soon.~
- ----- Original Message -----
From: "Jeff Ruppert" jeff@...
To: "GSBN" GSBN@...
Sent: Wednesday, May 18, 2005 11:06 PM
Subject: Re: GSBN:More moisture problems - Southern California

> Bob,
> It seems as the years go by, we are all becoming quasi moisture experts.
>  As time goes by, we are going to see more of this, and it makes you
> wonder how long all of us will be in business if it becomes too
> widespread.  As Paul put it, it is part of straw bale growing up.


End of Digest

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