[Cob] Re: drain & larsen truss Mobile Home

[dirtcheapbuilder-Charmaine Taylor]

  the point is that cob and natural materials wont easily stick to any 
paper for more than a few minutes, this is why the mesh is used, the 
mesh actually holds it all up as a support 'frame'.   on standard 
buildings they frame it out in wood and OSB, cover with felt paper  
then staple wire mesh over and spray with cement stucco... since cement 
will dry fast and stick to the wire it is different than the cob.

  the message  is you do need a drain plane  against the metal or vinyl  
mobile walls.

cob may stick to the mesh against a metal wall, but may hold wetness 
from any sweating/condensation moving from the inside of the home to 
the exterior.

having building paper against the vinyl may let the moisture drain down 
the wall-facing side of the paper, and not pass to the cob side.

LARSEN TRUSS..

best way is to imagine two   straight back ladders facing each other 2 
feet apart attached to a 2x4    they are a foot  to 2' deep- and you 
pack the light straw between them to make a tall narrow tower.  if you 
hve a truss attached to every 2x4 you are making a thick wall INSIDE 
the structure-- which, of course you have planned for in the footage 
needed.
  wood pieces connecting between the 'ladders' support the weight of the 
infill and stabilize the whole.



On Apr 8, 2006, at 9:50 PM, Carrie J Horne wrote:

>  Charmaine (I think),
> How is the felt supposed to stay attached to the wall once the cob is
> attached to it?
> It seems like the weight of the cob will pull the felt off.  Or is that
> your point?
>
>> I put a section of wire mesh that I had lying around on a section of 
>> the
> siding and used light cob pressed into it.<
>
> Lee,
> How are you attaching the mesh to the walls?
>
>> With bale, one includes a layer of gravel between the structure and
> the bales as a drainage plane. <
>
> Barbara,
> How do you get the gravel to stay in place?  Do you just leave a gap
> between the bales and structure and then fill it in with gravel?  So 
> then
> the issue is one of how the bales are attached to the rest of the
> structure, and just happens to be done so across a gap.  It seems like
> something similar could be done with cob.
>
> Carrie
> Salt Lake City
>
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