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Cob interior walls and outer sip walls

 
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So im a building a sip home 32 by 32 feet with interior cob lined walls. I live in canada where winter gets to minus 50 Celsius. So the sips are only for insulation and vapor sealing and the cob is for thermal banking and aesthetics. I am putting infloor heat powerd by solar heat.
 MY question is because of this wall setup do I need to provide a vapor outlet on the in between side of the cob and sip OR should I just let it dry. I may dust in between the cob and sip walls with a desicant powder. Just seeing if there are ideas out there.  Any ideas or thoughts are welcome thankyou.
 
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I had the same exact idea. I was going to have the cob for aesthetics while avoiding most of it's problems. I was even thinking of having another material below the cob walls that's more resilient to water in case of a leak and just running traditional walls in the bathroom and by the kitchen. In Ontario too so I don't trust cob walls at all without a exterior insulation and traditional wall on the exterior
 
K Carter
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Im thinking now I'll just do a sip wall with a 10mm poly vapor barrier and either cob or a gabon type rock wall.
 
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Location: Bendigo , Australia
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A vapour barrier may cause mould to grow. I think more research is required. Normally earth walls have no vapour barrier,
and if a cement based layer is installed, problems occur because of moisture, but if a lime based plaster is used,
moisture is not trapped, thus mould and rot does not occur
 
John C Daley
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Location: Bendigo , Australia
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From vapour barrier info

Do I Need a Vapor Barrier?
Once thought to be essential throughout a home or office, vapor barriers are now strongly recommended only for certain conditions, and methods for creating a vapor barrier must be tailored to fit the climate, region, and type of wall construction. For example, the recommended vapor barrier in a home or office in a humid southern climate built with brick varies greatly from creating a vapor barrier in a cold climate in a home built with wood siding. Always refer to current local code recommendations when deciding if and how to install vapor barriers.

Avoid adding interior vapor barriers where the outer wall construction already includes a material with vapor barrier properties.

Most authorities recommend vapor barriers in certain situations:

In areas with high humidity—such as greenhouses, rooms with spas or swimming pools, and bathrooms—vapor barriers are often recommended. Consult building inspection offices for local recommendations.
In very cold climates, the use of polyethylene plastic vapor barriers between insulation and interior wallboard may be beneficial, provided all air gaps into any wall and ceiling cavities are also blocked. The exterior face of the wall or floor cavity should remain permeable in order to allow dissipation of any moisture that does enter the wall cavity.
Very hot and humid climates may benefit from an exterior vapor barrier that keeps outside humidity from penetrating into walls.
Below-grade walls and floor slabs transmit ground moisture through concrete walls or slabs. A vapor barrier against the concrete surface is generally recommended before wood framing or flooring materials are installed.
Crawl spaces benefit from a polyethylene moisture barrier placed directly over the exposed earth.
 
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