[Strawbale]Re: convection in porous thermal insulation layers

Jan Hollan jhollan at amper....muni.cz
Mon Apr 25 14:02:33 CEST 2005

Seems I've deleted a row. The technology paragraph should read:

> Within bales, such vertical barriers may be made from gypsum most easily,
> as it is floats very well. A comb from thin pipes (4 mm to 6 mm outer
> diameter needles, 10 mm to 16 mm modulus) can serve for the injection,
> starting in mid-depth and going to the surface (starting at the opposite
> side does not work, the tips of needles become too dispersed to

  be able to form a thin, continuous barrier to airflow).  Four injections

> per bale
> are needed. 10 kg of gypsum per bale should suffice to create two vertical
> gypsum boards, dividing the bale into thirds. The final price of such
> bales will be however reach at least a fourth of the commercial insulation
> price, due to the gypsum costs.

I hope however even 4 kg of gypsum per bale should do.

On the other side, injecting thick clay-gypsum layers into a bale (sided
by smooth boards during this operation) might change it into a loadbearing
giant brick which could be still handled manually by two people with
suitable tools. The stiff ``boards'' inside the bales could be connected
with mortar from the same stuff, avoiding the need for connecting bales
with another elements.

Or, thick layers might be perhaps injected through the whole height of a
bale, after laying it onto the wall. This would be least labour-intesive.


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