Cob Wall Abutting Another Wall -- Okay?

Hi Everybody,

I would like to know if you can build a cob wall that abuts a stick frame wall (basically a two layer wall) or if cob requires being able to fully breathe on both sides.  Details:

Room 1 needs to be insulated but I'd like to be able to use some thermal mass to bank heat.

Room 2 does not need to be insulated but will still be inside the structure.

I live in upper valley NH, zone 4, with cold winters and mild humid summers.

This will be a stick-frame shed with exterior walls insulated using spray-foam.  The one cob wall in the middle segregating the two sections of the shed would bank heat for one room but not the other so this is why I was thinking of abutting the cob wall to another spray-foam insulated stick frame wall.  This project is intended to be a functional shed that's half office, half used for garden stuff, but also I'd like to use it as an experiment/opportunity to get my hands dirty with building cob so that I'm less likely to screw it up on a bigger project in the future.

Thanks for any input!!

Sounds like you want the interior wall to be mass with insulation on one side and want to use cob as the mass, so why not use straw as the insulation half and that way the wall still breathes.... I would consider this a light straw clay wall with cob on one side.  This combo is compatible

I think you have a good idea Aaron. A cob wall doesn't have to breath, you just need to watch the humidity. In an attemp to make their walls water proof, many people apply layer after layer of boiled linseed oil, and the by product is that the wall doesn't breath very well afterwards.