[GSBN] OSB inside walls

[Derek Roff]

I agree with Anni.  It is possible that OSB in Portugal has some differences from what I have seen in the USA, but I would want good health and safety evidence before I would want the material inside my house.

Another concern, which follows on to Dave Howorth’s questions, is the probable space between the interior surface of the OSB and the adjacent surface of the bales.  Is there a variable air gap in between, as would be normal with the irregular surface of an unplastered bale wall?  If so, this would be an excellent habitat for insects, some rodents, many molds, and any enterprising fires that might somehow get started in the interior of the house or wall.  Even without those problems, convection loops would decrease the thermal efficiency of the wall.

Since it is described as having ‘prefabricated strawbale walls’, the OSB may not be immediately adjacent to the straw.  It would be great to know more about the wall structure and its layers.

Derek

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




On Aug 19, 2024, at 4:18 PM, Anni Tilt <anni at arkintilt.com<mailto:anni at arkintilt.com>> wrote:

Hi there

In general we don’t use OSB adjacent to straw bale walls as they are not very breathable (note that we have used plywood, which has a higher perm rating, on the interior of a hybrid bale-insulated frame wall).  Additionally, OSB tends to off-gas - not good in an interior environment.
I don’t know about the specific coating being proposed on the interior, but a clay paint might be easy and  low cost (although perhaps not as durable).

Or might I suggest having a workshop to have plasterers join from around the world - plastering destination vacations!  I might even consider signing up!

best
Anni Tilt

Arkin Tilt Architects  Ecological Planning & Design
1101 8th Street, #180
Berkeley, CA 94710
510.528.9830
510.418.9788 mobile
www.arkintilt.com<http://www.arkintilt.com/>


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