[GSBN] Gsbn Digest, Vol 71, Issue 8

Tue Jun 27 23:32:36 UTC 2017

Thanks for your insights Lance, Rikki, and John!   

So far I haven't been asked to work on straw bale walls with paint on the
exterior--just those with interior latex painted walls.   I have seen that
once before though.  Someone had applied a few coats of elastomeric stucco
paint over exterior lime-cement plastered straw bale walls.  The paint
manufacturer's technical staff reported that the paint was vapor permeable,
but I wondered how additional layers of paint would impact this--how much
does each successive layer of paint compromise permeability, if at all?   I
don't know what became of that house; it's in an area with wet, cold
(freezing) winters that receives plenty of snow, and hot dry summers, much
like where I work.   

That may be the biggest problem with paint--it invites more paint!  Not even
getting into the high embodied energy cost of paint, what do additional
coats of latex paint do to the wall's vapor permeability?  If the first one
or two coats (inside or out) don't pose a serious problem, what happens if
it's repainted every five or ten years?  A building meant to last
one-hundred years might have lots of paint on its walls!   

At least in regions with hot, dry summers and cold, wet winters--how many
more layers of latex paint can be harmlessly applied?   If nothing else, the
plastered straw bale wall's ability to moderate interior humidity might be
diminished, but that begs the question because hygric capacity would seem to
depend on the permeability of a material so it absorbs and releases water
vapor.

I suspect that if summers here were hot and humid, and the straw bale
structure was air conditioned, moisture might be driven into the wall where
it might slow down, or even stop and accumulate at a less permeable
membrane.  Not that long ago it was common in conventional construction to
attach a vapor barrier to the warm side of the walls, which lead to many
walls rotting due to vapor drive.  In fact, that may contribute to the
confusion.   If water vapor is constantly diffusing through building
materials from a warm, humid side of a wall to a cold, dry side, then in
areas with warm, humid summers vapor is driven toward the interior of an
air-conditioned home, and in the winter, vapor drive is toward the exterior.
But what happens when the equation is different--when summers are warm and
dry (no air conditioning in the SB home) and winters are cold and wet?  

Since both of the homes I saw recently had latex painted interior straw bale
wall surfaces and the surfaces were rough and uneven (think popcorn, or
cottage cheese) which the new owners didn't care for, I may end up removing
the latex paint along with the rough textured plaster just to smooth and
flatten the walls a bit before applying a lime wash or finish coat.   If I
have a chance to peek inside the wall I'll report back any findings.

Jim

Jim Reiland
Many Hands Builders
541-899-1166
541-200-9546 cell
jim at manyhandsbuilders.com
www.manyhandsbuilders.com

-----Original Message-----
From: Gsbn [mailto:gsbn-bounces at sustainablesources.com] On Behalf Of
gsbn-request at sustainablesources.com
Sent: Monday, June 26, 2017 6:28 PM
To: gsbn at sustainablesources.com
Subject: Gsbn Digest, Vol 71, Issue 8

Send Gsbn mailing list submissions to
	gsbn at sustainablesources.com

To subscribe or unsubscribe via the World Wide Web, visit
	http://sustainablesources.com/mailman/listinfo.cgi/gsbn
or, via email, send a message with subject or body 'help' to
	gsbn-request at sustainablesources.com

You can reach the person managing the list at
	gsbn-owner at sustainablesources.com

When replying, please edit your Subject line so it is more specific than
"Re: Contents of Gsbn digest..."

Today's Topics:

   1. Re: latex paint on lime or cement plastered straw bale walls
      (Rikki Nitzkin)
   2. Re: latex paint on lime or cement plastered straw bale walls
      (Lance Kairl)
   3. Straw bale building in tropical areas (No? Solsona)
   4. Re: Straw bale building in tropical areas (Derek Stearns Roff)

----------------------------------------------------------------------

Message: 1
Date: Sun, 25 Jun 2017 13:35:59 +0200
From: Rikki Nitzkin <rikkinitzkin at gmail.com>
To: Global Straw Building Network <gsbn at sustainablesources.com>
Subject: Re: [GSBN] latex paint on lime or cement plastered straw bale
	walls
Message-ID: <A6090914-BF4D-4D06-AF29-8D813F977CBF at gmail.com>
Content-Type: text/plain; charset=utf-8

Hi Jim, 

you say "I occasionally see is latex paint on the interior of plastered
straw bale walls?. 

not on the outside?

I have never used latex paint on SB walls, but i do know it is LESS (not
saying ?not at all?) problematic to have the inside of the house sealed with
a vapor barrier- since this keeps the moisture inside the house, instead of
the walls. As long as the outside plaster is more vapor-permeable than the
inside, it should not be a problem. I even know a guy in Germany who made a
SB sauna. Inside completely sealed to vapor and moisture, and outside a very
permeable earthen plaster.

I would be more worried if the paint/cement was on the outside.

Rikki

------------------------------

Message: 2
Date: Mon, 26 Jun 2017 07:25:26 +0930
From: "Lance Kairl" <sabale at bigpond.com>
To: "'Global Straw Building Network'" <gsbn at sustainablesources.com>
Subject: Re: [GSBN] latex paint on lime or cement plastered straw bale
	walls
Message-ID: <000001d2edfd$c2bdc090$483941b0$@bigpond.com>
Content-Type: text/plain; charset="utf-8"

HI Jim,
You seam to have similar weather conditions to us here in areas of South
Australia , I have removed straw from  cement rendered ( stucco) wall just a
few days ago,  straw as fresh as  it was 17 years ago when it was put in.
And a few years ago  in repairing  a 50 year old straw panel ( strammit
panel  , 50mm thick straw bound by wire ) home.( all sorts of plaint
coatings), only had damage to the straw where water had got in.
Always  check the straw in the wall  ( behind electrical wall sockets  ,  a
small hole  the can be sealed afterwards).

Where low Relative humidity , and liveable outside  temperatures  do not
(often) get extreme it appears to me the risk to straw is mostly from direct
ingress of free moisture ( water).
Maintenance and repair to surface cracks that allow moisture in is the main
concern, especially if the straw is getting wet at every rain event.  

I have long held the opinion  that I have the best climate to build straw
bale houses in, that is  warm, dry , and low relative humidity.
I am glad there may be others , low risk ( places in the world) .
 I respect the wisdom, skill and work of those building in   the high risk
areas, being snow covered areas ,  below zero degrees outside and  a warm  ,
high humidity , inside , its got to be concerning
having a dew point  within the width of the wall.

While the thought of sealing up the surface of a bale wall still makes me
nervous , my  experience  makes me more concerned about free moisture
ingress, Especially in areas similar to my  local climate . (  50km away
the rainfall can be 3 x  my rain fall and sustained lower temperatures  over
winter and  higher Relative humidity in summer)

IN CONCLUSION
Breathable  surface  coatings would always be recommended.
And caution should be  high on the list when  retro work is undertaken, or
consulting on an existing property.
Is there a small grain dryer or  building dehumidifier  that could ( cost
effectively) be  installed to  give some confidence  about  the integrity of
the straw.
And only with caution and some local wisdom  would I have the confidence say
" it will be ok"
It all needs careful consideration.

Cheers lance
House of Bales

-----Original Message-----
From: Gsbn [mailto:gsbn-bounces at sustainablesources.com] On Behalf Of john
rehorn
Sent: Saturday, 24 June 2017 7:40 AM
To: Global Straw Building Network <gsbn at sustainablesources.com>
Subject: Re: [GSBN] latex paint on lime or cement plastered straw bale walls

It would be cool if you could get to the bales and inspect them, even in a 4
inch by 4 inch region.  Also, interviewing the residents to gain insight as
to the impact they have had regarding moisture.  This would help us all. I
have a friend who did an addition to an sb after 20 or so years.  They used
cementatious stucco on the outside, and I do believe they put up felt and
then stucco wire.  The removed bales looked as fresh as when they were put
in.  Southwest Colorado is a dry climate with monsoonal moisture in the late
summer and sometimes heavy snow and even winter rain.  This observation goes
against (non)conventional wisdom.

Seems like the best method would be to score the plaster aggressively and
skim a nice color coat over everything.  Where clay meets clay, there would
be moisture migration.

I have another friend who procured a bale from a remodel of a 150 year old
Nebraska sb.  The bale was yellow prairie grass and there was even a moulted
snake skin in the bale.  All looked like it could have been pulled out of a
barn having been stored a year or two.  The stucco looked like a lime
render, and I wouldn?t have been surprised if at some point in the life of
the house, someone took latex to the walls.

This is all just anecdotal, but I hope useful.

John Rehorn 
> On Jun 23, 2017, at 1:53 PM, Jim Reiland <jim at manyhandsbuilders.com>
wrote:
> 
> Hi everyone,
> 
> I'm fortunate to have over forty permitted straw bale residences here 
> in my S. Oregon county; as these homes resell and second owners decide 
> to make changes I sometimes have an opportunity to see how the walls--some
of them
> twenty years old--have held up.   
> 
> Something I occasionally see is latex paint on the interior of 
> plastered straw bale walls.  I'm recalling that a few coats of latex 
> paint may be fairly permeable, but that many more layers could 
> effectively seal the wall surface, preventing moisture vapor from moving
through the wall.
> 
> So far I have run into latex paint at only three coats--a primer and two
> cover coats--over a lime or cement-lime plaster.   
> 
> Is the straw bale wall in any danger with three coats of latex paint?  
> I understand that latex paints have different characteristics--some 
> may be more permeable than others--but in my experience the new owners
don't have
> access to that information.   
> 
> If the paint needs to be removed so a more permeable color alternative 
> can be used, e.g. pigmented lime wash or plaster, etc., does anyone have
> experience with removing it?   I imagine that may depend on the texture of
> the plaster.  Yesterday I saw a painted finish plaster with the texture of
> popcorn--it may have been sprayed on--sure didn't look troweled!   A few
> weeks ago I saw a painted wall that was much smoother.    Sandpaper, a
> scraper, and possibly paint remover might work on the smoother 
> finish...but not on the more textured surface.
> 
> If the straw bale wall is OK at two or three coats, is there a tipping 
> point where additional latex paint layers effectively seal the wall?
> 
> The climate here in S. Oregon is similar to most of N. California--hot 
> dry summers, relatively mild, wet winters characterized by regular rainy
spells
> alternating with dry periods.   Most of the straw bale homes I have seen
do
> not have mechanical air conditioning, so while they may be naturally 
> cool inside when it's hot outside, it could be a different challenge 
> than is faced by people who use mechanical air conditioning in regions 
> with hot, humid summers and cold, wet winters.
> 
> Thanks for any experiences, insights, and explanations you can offer on
this
> subject.   I apologize if this topic has come up before and answers are
> already somewhere in the archives.
> 
> Jim
> 
> Jim Reiland
> Many Hands Builders
> 541-899-1166
> 541-200-9546 cell
> jim at manyhandsbuilders.com
> www.manyhandsbuilders.com
> 
> 
> 
> -----Original Message-----
> From: Gsbn [mailto:gsbn-bounces at sustainablesources.com] On Behalf Of 
> gsbn-request at sustainablesources.com
> Sent: Friday, June 23, 2017 10:23 AM
> To: gsbn at sustainablesources.com
> Subject: Gsbn Digest, Vol 71, Issue 3
> 
> Send Gsbn mailing list submissions to
> 	gsbn at sustainablesources.com
> 
> To subscribe or unsubscribe via the World Wide Web, visit
> 	http://sustainablesources.com/mailman/listinfo.cgi/gsbn
> or, via email, send a message with subject or body 'help' to
> 	gsbn-request at sustainablesources.com
> 
> You can reach the person managing the list at
> 	gsbn-owner at sustainablesources.com
> 
> When replying, please edit your Subject line so it is more specific 
> than
> "Re: Contents of Gsbn digest..."
> 
> 
> Today's Topics:
> 
>   1. Re: Load-bearing straw bale idea (Derek Stearns Roff)
>   2. Re: Load-bearing straw bale idea (Derek Stearns Roff)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Fri, 23 Jun 2017 17:09:02 +0000
> From: Derek Stearns Roff <derek at unm.edu>
> To: Global Straw Building Network <gsbn at sustainablesources.com>
> Subject: Re: [GSBN] Load-bearing straw bale idea
> Message-ID: <AA7E4B63-7ABD-4DDD-9181-887DB4E2B7FF at unm.edu>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi, Rikki,
> 
> It sounds like your architect plans what we call a ?gable roof? in the US.
> I don?t know if anyone has tried the design shown in your architect?s 
> drawing, but I would advise against it.  It asks bales to do what they 
> are least good at- resisting point loads/forces.  A ridge beam in this 
> kind of roof framing will bear about half the weight of the roof.  
> That isn?t too bad for a lightweight metal roof on a sunny day in 
> summer.  When the roof is covered by two feet of snow, or clay tiles, 
> or a couple of layers of asphalt shingles, a large amount of weight is 
> concentrated on one spot in the top bale, and on the gap between two bales
on the second row.
> 
> The thin wooden panels shown will help a little bit, but they, too, 
> will flex under load.  When roofing loads are distributed evenly, I 
> don?t think that ?creep?, the slow deformation of bales under 
> prolonged load, is a severe problem in most strawbale houses.  In this 
> design, creep would probably be a factor, and the ridge beam could get a
little lower each year.
> 
> If the pyramid of bales shown in the drawing was faced with plywood on 
> the inner and outer faces, it would increase the resistance to 
> deflection by about 1000 times, I?m guessing.  This would be a much 
> more reliable method of transferring the roof loads to the wall, and 
> then to the foundation.  It might be necessary to shave those bales 
> down by the thickness of the plywood, to get the dimensions that you 
> want from the bale and plywood composite.
> 
> Other architects and engineers on this list may have better ideas.  
> This is the best approach that I have thought of, which remains very 
> similar to the architect?s drawing.
> 
> Best wishes,
> Derek
> 
> Derek Roff
> derek at unm.edu<mailto:derek at unm.edu>
> 
> 
> 
> 
> On Jun 23, 2017, at 9:06 AM, Rikki Nitzkin 
> <rikkinitzkin at gmail.com<mailto:rikkinitzkin at gmail.com>> wrote:
> 
> Hi all,
> 
> I forward a petition from a Spanish architect who wants to know if his 
> idea has been tried, and if it worked.
> 
> He is planning to build a Load-bearing SB home. The roof will have two 
> ?waters? (what is that called in english?)- creating a triangular gap 
> on both sides of the roof.
> 
> He wants to try to put the main beam (Spanish architecture doesn?t use 
> triangular rafters, but a main roof beam, with the other beams resting 
> on
> it) directly on the bales. His idea is to put a wooden panel on top of 
> each row that is above the roof-plate, until reaching the main beam- 
> using very well compressed bales.
> 
> Has anyone tried this?
> 
> Here is a drawing of the idea:
> 
> <hastial Alejandro.jpeg>
> _______________________________________________
> Gsbn mailing list
> Gsbn at sustainablesources.com<mailto:Gsbn at sustainablesources.com>
> http://sustainablesources.com/mailman/listinfo.cgi/gsbn
> 
> -------------- next part -------------- An HTML attachment was 
> scrubbed...
> URL:
> <http://sustainablesources.com/pipermail/gsbn/attachments/20170623/22d
> 84be8/
> attachment-0001.html>
> 
> ------------------------------
> 
> Message: 2
> Date: Fri, 23 Jun 2017 17:17:18 +0000
> From: Derek Stearns Roff <derek at unm.edu>
> To: Global Straw Building Network <gsbn at sustainablesources.com>
> Subject: Re: [GSBN] Load-bearing straw bale idea
> Message-ID: <C2BE6169-431E-4E22-B21B-EB00F61FDBF9 at unm.edu>
> Content-Type: text/plain; charset="utf-8"
> 
> I was wrong in my last message, saying the weight on a gable roof 
> ridge beam is 1/2 the total weight of the roof.  I should have said 
> the roof beam takes
> 2/3 of the weight.  (This is in a roof using simple rafters, as Rikki 
> indicated, rather than trusses.)
> 
> Derek
> 
> Derek Roff
> derek at unm.edu<mailto:derek at unm.edu>
> 
> 
> 
> 
> On Jun 23, 2017, at 11:09 AM, Derek UNM 
> <derek at unm.edu<mailto:derek at unm.edu>> wrote:
> 
> Hi, Rikki,
> 
> It sounds like your architect plans what we call a ?gable roof? in the US.
> I don?t know if anyone has tried the design shown in your architect?s 
> drawing, but I would advise against it.  It asks bales to do what they 
> are least good at- resisting point loads/forces.  A ridge beam in this 
> kind of roof framing will bear about half the weight of the roof.  
> That isn?t too bad for a lightweight metal roof on a sunny day in 
> summer.  When the roof is covered by two feet of snow, or clay tiles, 
> or a couple of layers of asphalt shingles, a large amount of weight is 
> concentrated on one spot in the top bale, and on the gap between two bales
on the second row.
> 
> The thin wooden panels shown will help a little bit, but they, too, 
> will flex under load.  When roofing loads are distributed evenly, I 
> don?t think that ?creep?, the slow deformation of bales under 
> prolonged load, is a severe problem in most strawbale houses.  In this 
> design, creep would probably be a factor, and the ridge beam could get a
little lower each year.
> 
> If the pyramid of bales shown in the drawing was faced with plywood on 
> the inner and outer faces, it would increase the resistance to 
> deflection by about 1000 times, I?m guessing.  This would be a much 
> more reliable method of transferring the roof loads to the wall, and 
> then to the foundation.  It might be necessary to shave those bales 
> down by the thickness of the plywood, to get the dimensions that you 
> want from the bale and plywood composite.
> 
> Other architects and engineers on this list may have better ideas.  
> This is the best approach that I have thought of, which remains very 
> similar to the architect?s drawing.
> 
> Best wishes,
> Derek
> 
> Derek Roff
> derek at unm.edu<mailto:derek at unm.edu>
> 
> 
> 
> 
> On Jun 23, 2017, at 9:06 AM, Rikki Nitzkin 
> <rikkinitzkin at gmail.com<mailto:rikkinitzkin at gmail.com>> wrote:
> 
> Hi all,
> 
> I forward a petition from a Spanish architect who wants to know if his 
> idea has been tried, and if it worked.
> 
> He is planning to build a Load-bearing SB home. The roof will have two 
> ?waters? (what is that called in english?)- creating a triangular gap 
> on both sides of the roof.
> 
> He wants to try to put the main beam (Spanish architecture doesn?t use 
> triangular rafters, but a main roof beam, with the other beams resting 
> on
> it) directly on the bales. His idea is to put a wooden panel on top of 
> each row that is above the roof-plate, until reaching the main beam- 
> using very well compressed bales.
> 
> Has anyone tried this?
> 
> Here is a drawing of the idea:
> 
> <hastial Alejandro.jpeg>
> _______________________________________________
> Gsbn mailing list
> Gsbn at sustainablesources.com<mailto:Gsbn at sustainablesources.com>
> http://sustainablesources.com/mailman/listinfo.cgi/gsbn
> 
> 
> -------------- next part -------------- An HTML attachment was 
> scrubbed...
> URL:
> <http://sustainablesources.com/pipermail/gsbn/attachments/20170623/181
> c1eb8/
> attachment.html>
> 
> ------------------------------
> 
> Subject: Digest Footer
> 
> _______________________________________________
> Gsbn mailing list
> Gsbn at sustainablesources.com
> http://sustainablesources.com/mailman/listinfo.cgi/gsbn
> 
> 
> ------------------------------
> 
> End of Gsbn Digest, Vol 71, Issue 3
> ***********************************
> 
> _______________________________________________
> Gsbn mailing list
> Gsbn at sustainablesources.com
> http://sustainablesources.com/mailman/listinfo.cgi/gsbn

_______________________________________________
Gsbn mailing list
Gsbn at sustainablesources.com
http://sustainablesources.com/mailman/listinfo.cgi/gsbn

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

------------------------------

Message: 3
Date: Mon, 26 Jun 2017 23:26:21 +0200
From: No? Solsona <noe at anarchitecture.org>
To: Global Straw Building Network <gsbn at sustainablesources.com>
Subject: [GSBN] Straw bale building in tropical areas
Message-ID: <2309C92C-6EC1-4707-A60D-355A1A0D1345 at anarchitecture.org>
Content-Type: text/plain; charset=utf-8

Hello Balers,

Hope you are all fine in the full season arriving ?

Back from the ESBG in Venise where I made great contact to go and give
courses on plastering bales and mechanization of plastering, I got one
request for building with bales in Benin.

Did any one of you did such experience or heard of such one in this kind of
area?s ?

I know that I have always heard that we can build with bales all around the
world where there is straw, but not in tropical places.
But I also hear that it could be possible if we have a vapor block membrane
in the outside, and clay plastering in the inside with a good and strong air
conditioning system.
What do you think ?

Thank you very much in advance for your brith advices ;)
No? from France

CalyClay
No? Solsona 
ZI des Monts du Matin
100 rue des Lauriers
26730 EYMEUX
France
P. : +33 (0) 617 421 050
T. : +33 (0) 482 533 110
F. : +33 (0) 482 533 111
noe at calyclay.com
www.calyclay.com

------------------------------

Message: 4
Date: Tue, 27 Jun 2017 01:25:04 +0000
From: Derek Stearns Roff <derek at unm.edu>
To: Global Straw Building Network <gsbn at sustainablesources.com>
Subject: Re: [GSBN] Straw bale building in tropical areas
Message-ID: <B11A53B4-D69A-4C28-A12A-8D766E5CC881 at unm.edu>
Content-Type: text/plain; charset="utf-8"

According to the link below, Benin in every month is just about the same
temperature as Marseille in the summer.  So it is not excessively hot, but
it is always pretty warm.  Lower summer temperatures than Houston, or some
other USA locations with SB houses.  High humidity, certainly.  Using air
conditioning in a hot, humid climate increases the risk of condensation
within the bale wall, so a careful plan for handling moisture will be quite
important.

http://www.benin.climatemps.com

Derek

Derek Roff
derek at unm.edu<mailto:derek at unm.edu>