[Strawbale]Re: GSBN:Danish Testing on SB walls

Martin Oehlmann martin.oehlmann at hetnet...
Thu Sep 23 15:22:37 CEST 2004


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

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
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
Thanks and best wishes,
Martin Oehlmann
Den Haag

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

----- Original Message ----- 
From: "Lars Keller" <larskeller at livinghouses...>
To: "European Strawbale List" <strawbale at amper....muni.cz>;
<echoventures at vodafone....nz>; "Global Straw Bale Network"
<GSBN at lists....com>
Cc: "Bruce King" <bruce at ecobuildnetwork...>; "Dirk Scharmer" <ds at fasba...e>
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 Jørgen Munch-Andersen
  MSc (CivEng), PhD, Head of Department
  +45 4574 2388
  jma at by-og-byg...
the results are also partly available in English:

The test reports (in Danish) are available via the following links:
- fire test of clay as a surface cover material:
- 30min fire test of clay plastered non-loadbearing sb-wall:
- air-sound-insulation of clay plastered non-loadbearing sb-wall:
- capillary hight rise of mussell shells, three densities:
- organic and microbial dust as a healtrisk in strawbale building:
- water vapour transmission properties of clay plaster with various surface
treatments / additives: http://www.by-og-byg.dk/download/pdf/423-8a.pdf
- water vapour transmission properties of straw
- 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): http://www.by-og-byg.dk/download/pdf/423-8c.pdf
- settling of non-loadbearing and loadbearing sb-walls after two moisture
cycles: http://www.by-og-byg.dk/download/pdf/423-8d.pdf
- thermal insulation of earthplastered sb-wall, bale lying flat:
- thermal insulation of earthplastered sb-wall, bale on edge:
- thermal insulation of non plastered straw bale, on edge, flat, two
different densities: http://www.by-og-byg.dk/download/pdf/danak.pdf
- thermal insulation of mussell shells, three different densities:

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


----- Original Message ----- 
From: <echoventures at vodafone....nz>
To: <strawbale at amper....muni.cz>
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
> ____________________________________________________
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> Send all messages to:
> Strawbale at amper....muni.cz
> Archives, subscription options, etc:
> http://amper.ped.muni.cz/mailman/listinfo/strawbale
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