Cob: strawbale/cob on the inside

[Ric Allan]

But if the thermal mass is insulated from the outside sun, how does it pick
up the energy to re-radiate......


-----Original Message-----
From: Matthew HALL(SED) <M.Hall at shu.ac.uk>
To: kerdor at alberta.com <kerdor at alberta.com>
Cc: coblist at deatech.com <coblist at deatech.com>
Date: Tuesday, February 12, 2002 8:57 AM
Subject: Re: Cob: strawbale/cob on the inside


>Kerry
>Very interesting concept. It makes good sense to me to have the cob on the
inside wall and the
>straw on the outside. Radiant heat loss to the atmosphere from the cob
thermal mass store will be
>minimised by the high insulation layer of the strawbale. How will you
ensure the strawbales are
>durable enough to withstand your climate? Cement-based render perhaps? Lime
may be better as it
>would allow the structure beneath to breath; very inportant if you want to
prevent rot in your
>straw bales.
>
>>Just thinking about building in my area, cold Alberta Canada.  I am a
>>huge lover of the cob concept but in my climate I am feeling and have
>>been told by experienced  cobbers that it may not be a positive thing
>>for up to  -30*C weather.
>Cold is only a problem if there is also moisture. Without it there cannot
be frost and so your
>material won't get damaged in this way. I remember you told me your climate
is very dry but cold so
>you may be okay. Make some trial samples and leave them outside to see what
happens.
>
>>
>>Now, if I  prepare my interior walls with   stucco, cob, whatever ( to
>>cover the bales)  how do I attach  cob structure (ie.  furniture, stoves)
>>to these prepped walls without the cob structures falling off? Do I have
>>to cob around rebar attached to my walls?   Will
>>my house move and crack the interior cob?
>Cracking can be reduced/prevented with adequate use of natural fibres in
the mix. You may also be
>able to leave some extra long fibres exposed from the wall to help tie your
furniture in with the
>wall itself. If you use rebar make sure it is embedded very deep to prevent
rust forming. Hardwood
>may act as a better framework for your furniture and it too will be
preserved if embedded
>correctly.
>
>>>Is my idea feasable?
>Yes, very much so. I have seen buildings like this before with an insulated
earth wall as you are
>describing; rammed earth on the inside and straw bale or other insulating
material on the outside.
>It should not add too greatly to the cost but your walls will be immensely
thick and you will need
>a lot of labour to build this project!
>Good luck
>Matthew
>____________________________________________________________________
>Matthew Hall - PhD Research Student
>Centre for the Built Environment
>Unit 9 Science Park
>Sheffield Hallam University
>Pond Street
>Sheffield S1 1WB
>England
>
>Tel: +44 (0) 114 225 3200
>Fax: +44 (0) 114 225 3206
>E-mail: M.Hall at shu.ac.uk
>
>
>
>
>
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