Cob building?

[Daffodils At The Sea]

Anyone here done this? I want to build a small seed-starting "greenhouse" with an insulated cobb back wall and an opposite glass wall to let the heat in. I know the basics, needs an overhanging roof, keep it up off the wet soil, I definitely have the right soil, super heavy clay,. I've seen some mixtures with sawdust and some with sturdy straw, and I wonder who has experience with one over the other.

Any experience and/or stories?

 

[Daffodils At The Sea]

I decided against this because it needs big eave overhangs to protect the cob, and that isn't going to work on a passive solar building. So maybe for another application...

 

[the_whingnut]

Have you seen this? Its an alternative to cob http://www.cordwoodmasonry.com

 

[Daffodils At The Sea]

I have seen that, and as much as I love the aesthetics of it, I've read it weakens the cob. And my termites would dine on it almost instantly. I would love to include a few bottles, though, as art objects in any wall, which look really cool

 

[the_whingnut]

There is no cob in cord wood masonry its mortar and cedar, the center is filled with saw dust and lime mixture. The lime in the mortar and the insulation keeps the bugs out.

 

[~gd]

I decided against this because it needs big eave overhangs to protect the cob, and that isn't going to work on a passive solar building. So maybe for another application...

I aways thought that cob was treated like adobe ie sprayed with a thin mortar coat to protect against rain?

 

[the_whingnut]

it can be done mortar, but its usually not a mortar finish but a clay plaster finish.

 

[~gd]

it can be done mortar, but its usually not a mortar finish but a clay plaster finish.

In this area plaster is considered to be a soft finish and it seems to me that clay plaster would fail under heavy rain. Whatever

 

[the_whingnut]

The key to cob it a good foundation and roof with longer over hangs. They have cob houses and buildings in the UK that are over 300 years old. There is older temples in china built the same way. But they do need to be maintained every year. Cob is just like every other building type it requires maintenance.

 

[the_whingnut]

Here is a link http://cobhouse.net
It has more info on cob and construction