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GSBN: Digest for 9/23/04



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-> Re: GSBN:Danish Testing on SB walls
     by "Martin Oehlmann" martin.oehlmann@...
-> Re: Hydraulic Lime
     by Derek Roff derek@...
-> Re: Hydraulic Lime
     by "Martin Oehlmann" martin.oehlmann@...


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Date: 23 Sep 2004 07:36:59 -0600
From: "Martin Oehlmann" martin.oehlmann@...
Subject: Re: GSBN:Danish Testing on SB walls

Hello,

greetings also from Pascal Thepaut. He is rather busy in co-creating a small
community with 8 strawbalehouses to be built next spring near Dinan in
Brittany.

Like to share with some aspect of lime stuccoing and ask you some insights on
floor insulation for my dream project next year in Brittany.


1) For those who use lime from St. Astier (www.stastier.co.uk) which is
available in different countries.

St. Astier NHL2  is composed of 55-60% airlime and the rest hydraulic lime.
Use sharp sand: 
1. layer 1,5 parts of sand (2mm)  and 1 part of lime (drying period at good
weather about 10 days)

2. layer 2 parts of sand (2-4mm) and 1 part of lime

3. layer 3 parts of sand (4mm) and 1 part of lime

Stucco in total 30 mm.

Test: after 4 month continious rain 10 mm of the lime stucco will get wet and
it never will rain 4 month continously...

The lime expert at St. Astier already was familiar with applying lime on
strawbales and says consequently the salt at the sea nearby (100m) will not
enter more than 1 cm into the stucco. Would you agree?

2) Beside using wooden I-beams for the roof (Fermacell gipsonplate between
I-beams, dipped strawbales on Fermacell, 2 cm lime stucco, dampopen foil, 5 cm
air, 1cm wood and slate tyles) I think of the following floor construction:

Prefab concrete steel reinforced beams on the foundation 50 cm above
groundlevel (necessary for the required septic tank, its overflow has to be 45
cm above the ground due to the rocky surface and a needed sandlayer of 70 cm
and 10 cm gravel). Between reinforced beams prefab "bio-briques" which is
baked tone with lots of air in between. On that 4 cm beton or would rammed
earth be an option? 

Than: strawbales on this beton (there is airventilation underneath). On the
strawbales a metal net connected with floorheating tubes and on that 7 cm
beton and floortyles.

I would be interested in longterm experiences if there are any or suggestions
improving that floating or maybe better hanging floor, especially in view on
moisture from underneath. If the ground (vegetal level) becomes wet, some damp
will touch the bio-briques. Is there any formula to calculate the openings for
natural ventilation? The surface is 80 m2. The airspace between the briques
and the groundlevel can be between 20 and 50 cm. What's wise for keeping the
strawbales as floorinsulation forever dry?

Thanks and best wishes,

Martin Oehlmann

Den Haag

0031-70-3650410



PS: For those who know Moulin du Roz: the wheel turns perfectly. Its just
WONDERFUL!










- ----- Original Message ----- 
From: "Lars Keller" larskeller@...
To: "European Strawbale List" strawbale@...;
echoventures@...; "Global Straw Bale Network"
GSBN@...
Cc: "Bruce King" bruce@...; "Dirk Scharmer" ds@...
Sent: Wednesday, September 22, 2004 11:09 PM
Subject: GSBN:Danish Testing on SB walls


Dear Marcus et al.

The Danish sb-testprogramme has produced several results now available via the
internet.
Thanks to a lot of work by Jorgen Munch-Andersen 
  MSc (CivEng), PhD, Head of Department
  +45 4574 2388
  jma@...
the results are also partly available in English:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/jma_slides_halmhuse.pdf";>http://www.by-og-byg.dk/download/pdf/jma_slides_halmhuse.pdf</a>

The test reports (in Danish) are available via the following links:
- - fire test of clay as a surface cover material:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/pg10809.pdf";>http://www.by-og-byg.dk/download/pdf/pg10809.pdf</a>
- - 30min fire test of clay plastered non-loadbearing sb-wall:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/pg10810.pdf";>http://www.by-og-byg.dk/download/pdf/pg10810.pdf</a>
- - air-sound-insulation of clay plastered non-loadbearing sb-wall:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/p870072.pdf";>http://www.by-og-byg.dk/download/pdf/p870072.pdf</a>
- - capillary hight rise of mussell shells, three densities:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/2001-02-21.pdf";>http://www.by-og-byg.dk/download/pdf/2001-02-21.pdf</a>
- - organic and microbial dust as a healtrisk in strawbale building:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/amislutrapport.pdf";>http://www.by-og-byg.dk/download/pdf/amislutrapport.pdf</a>
- - water vapour transmission properties of clay plaster with various surface
treatments / additives: <a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/423-8a.pdf";>http://www.by-og-byg.dk/download/pdf/423-8a.pdf</a>
- - water vapour transmission properties of straw
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/423-8b.pdf";>http://www.by-og-byg.dk/download/pdf/423-8b.pdf</a>
- - moisture accumulation of sb-walls plastered with clay plaster on the
inside (warm side) and clay plaster or lime plaster on the outside (cold
side): <a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/423-8c.pdf";>http://www.by-og-byg.dk/download/pdf/423-8c.pdf</a>
- - settling of non-loadbearing and loadbearing sb-walls after two moisture
cycles: <a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/423-8d.pdf";>http://www.by-og-byg.dk/download/pdf/423-8d.pdf</a>
- - thermal insulation of earthplastered sb-wall, bale lying flat:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/55650-34.pdf";>http://www.by-og-byg.dk/download/pdf/55650-34.pdf</a>
- - thermal insulation of earthplastered sb-wall, bale on edge:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/55650-35.pdf";>http://www.by-og-byg.dk/download/pdf/55650-35.pdf</a>
- - thermal insulation of non plastered straw bale, on edge, flat, two
different densities: <a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/danak.pdf";>http://www.by-og-byg.dk/download/pdf/danak.pdf</a>
- - thermal insulation of mussell shells, three different densities:
<a  target="_blank" href="http://www.by-og-byg.dk/download/pdf/danak.pdf";>http://www.by-og-byg.dk/download/pdf/danak.pdf</a>

Please pass on, and enjoy your reading.
Best regards,
Lars Keller

~~~

- ----- Original Message ----- 
From: echoventures@...
To: strawbale@...
Sent: Wednesday, September 22, 2004 3:48 PM
Subject: [Strawbale]Fire Testing on SB walls


> Help,
> 
> I'm building a SB house in Hungary and after getting permission for a wooden
framed cob house and applying for the modification of the building permit to
Sb walls, I have been turned down on the grounds of fire risk.
> Does anyone know of any certificates, tests or publications which documents
fire testing on strawbale walls in Europe and where I might find them? 
American/Canadian tests are no good for the building department here.  Or any
loopholes to get around this law?
> 
> Thanks,
> 
> Marcus
> 
> 
> 
> 
> 
> 
> ____________________________________________________
>     European strawbale building discussion list
> 
> Send all messages to:
> Strawbale@...
> 
> Archives, subscription options, etc:
> <a  target="_blank" href="http://amper.ped.muni.cz/mailman/listinfo/strawbale";>http://amper.ped.muni.cz/mailman/listinfo/strawbale</a>
> ____________________________________________________
> 
>

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Date: 23 Sep 2004 10:36:20 -0600
From: Derek Roff derek@...
Subject: Re: Hydraulic Lime

Does hydraulic lime have the vapor permeability of traditional high calcium
limes?  My guess would be that it doesn't, but I haven't seen any figures.
How does the vapor permeability of the St. Astier lime render compare with
standard lime and portland cement/lime renders?

While it is impressive to claim minimal water penetration in the render
after the equivalent of four months of continuous rain, what that really
tells us, is that the material has properties that we don't need.  As
noted, we never get four months of continuous rain.  Such claims appeal to
a reflexive "more is always better" enthusiasm, and often disguise the
negative side effects of excess.  I think it is more important to have good
vapor permeability than to have extreme water resistance.  Especially if
there are concerns about ground moisture entering the structure from under
the house.

Standard lime renders have adequate resistance to water penetration, even
in wet British and French climates.  They have excellent vapor
permeability.  Lime putty can be stored for years.  The increased water
resistance of hydraulic lime is not needed, so far as I know.  Vapor
permeability is unknown (by me).  Hydraulic lime cannot be stored after
mixing with water.  Working time is limited.  In my view, these last two
factors make hydraulic limes inferior to standard limes for building
renders, especially for amateur builders.  No doubt there are some
situations where they would be appropriate.

Derek

- --On Thursday, September 23, 2004 3:18 PM +0200 Martin Oehlmann
martin.oehlmann@... wrote:

> St. Astier NHL2  is composed of 55-60% airlime and the rest hydraulic
> lime.


Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek@...



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Date: 23 Sep 2004 11:01:28 -0600
From: "Martin Oehlmann" martin.oehlmann@...
Subject: Re: Hydraulic Lime

Hi Derek,

thank you for your reflection. I guess hydraulic lime gets involved to speed
up the drying process in wet climates.

The problem with straw is, we need to protect it during the long drying
period when it can't yet protect us.

Strawbale floor Just phoned with Rene Dalmeijer who explained the technique
Werner Schmidt applied in Switzerland:

vertical tubes with airspace in the beton and fleece on them + gravel...

More reflections?

Best wishes, Martin





- ----- Original Message -----
From: "Derek Roff" derek@...
To: "GSBN" GSBN@...; "Martin Oehlmann"
martin.oehlmann@...; "European Strawbale List"
strawbale@...; echoventures@...
Cc: "Bruce King" bruce@...; "Dirk Scharmer" ds@...
Sent: Thursday, September 23, 2004 6:19 PM
Subject: Re: Hydraulic Lime


> Does hydraulic lime have the vapor permeability of traditional high
calcium
> limes?  My guess would be that it doesn't, but I haven't seen any figures.
> How does the vapor permeability of the St. Astier lime render compare with
> standard lime and portland cement/lime renders?
>
> While it is impressive to claim minimal water penetration in the render
> after the equivalent of four months of continuous rain, what that really
> tells us, is that the material has properties that we don't need.  As
> noted, we never get four months of continuous rain.  Such claims appeal to
> a reflexive "more is always better" enthusiasm, and often disguise the
> negative side effects of excess.  I think it is more important to have
good
> vapor permeability than to have extreme water resistance.  Especially if
> there are concerns about ground moisture entering the structure from under
> the house.
>
> Standard lime renders have adequate resistance to water penetration, even
> in wet British and French climates.  They have excellent vapor
> permeability.  Lime putty can be stored for years.  The increased water
> resistance of hydraulic lime is not needed, so far as I know.  Vapor
> permeability is unknown (by me).  Hydraulic lime cannot be stored after
> mixing with water.  Working time is limited.  In my view, these last two
> factors make hydraulic limes inferior to standard limes for building
> renders, especially for amateur builders.  No doubt there are some
> situations where they would be appropriate.
>
> Derek
>
> --On Thursday, September 23, 2004 3:18 PM +0200 Martin Oehlmann
> martin.oehlmann@... wrote:
>
> > St. Astier NHL2  is composed of 55-60% airlime and the rest hydraulic
> > lime.
>
>
> Derek Roff
> Language Learning Center
> Ortega Hall 129, MSC03-2100
> University of New Mexico
> Albuquerque, NM 87131-0001
> 505/277-7368, fax 505/277-3885
> Internet: derek@...
>



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