Cob: Re: Aluminun foil

[Matthew HALL(SED)]

K8
>> Maybe someone can clue me in as to the feasibility of putting a layer of
>> cob on the strawbale, then a sheet of aluminum foil reflecting toward the
>> interior, finishing with the rest of my cob wall.   My thinking is that a
>> none continuous layer of reflective material would reflect heat back into
>> the house and still not create a vapor barrier.
>> 
>> Let me know what you think.

I may be wrong on this but i believe aluminium foil reflects only radiant heat and not conducted
heat. If this is so then the layer of foil would serve no purpose buried inside a wall. Am i
incorrect in this assumption anyone?

Also, the idea of any non-porous barrier inside an earth wall/straw bale wall at the interface
between the two walls will probably result in interstitial condensation forming inside the outer
layers of the cob wall. Increased moisture content will alow its compressive strength to wall and
the cob will be likely to slump under its self weight.

I agree with Ocean, no need to worry about heat loss as the insulation will encapsulate this and
allow it to be stored in the mass walls. Contrary to what some might think, these types of
insulated thermal mass buildings have been built with a large degree of success in parts of the
world with very winter temperatures. Have a look in Reynold.s earthship vol 1 book 1991. for more
infor in insulated mass walls.

Hope this helps
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