Jeremy Nodine

Great info guys thanks, love this forum.

The trick to "thermal inertia," and higher R factors working in concert with one another in these "mass wall" systems is "air breaks." So, as an extreme example, say you went through the effort of using cob with a foam core thermal break. You would have to create and "air break" of at least 20 mm (~3/4) between the cob and the foam. These types of spaces can also be enhanced by the application of a "radiant barrier," but the air space in those applications must be "dead air space." With the foam to the outside of the cob mass wall, you will have to vent the air space back into the living space, which is fine to do, as the cob has little R factor to it in the first place, and the foam would then take the brunt of the thermal resistance work for the wall diaphragm. Then the exterior could be clad in wood board, shingle, stone, or a myriad of other systems.

Hmmm you got me thinking....so let me see if I follow you here, are you saying I could for example build a pallet frame to hold the foam then cob around that leaving air space and then vent at top and bottom of the walls and it would work? If so could I vent it to the outside? Would I even need a vent if it is fully encapsulated? I had already considered a pallet wall system with some form of insulation infill as it would likely save me time/labor overall.

A good friend of mine, living in Minnesota insulated his cob building with wool/lime. So far, it appears to work well with no troubles

That's pretty incredible to attempt cob in that climate. How exactly did he incorporate the insulation? How long has he lived in it? Any more info is much appreciated!

Thanks Jay! This is the kind of answer I was looking for. I live in zone 7b in the piedmont of South Carolina the specific location is Landrum S.C here are some numbers on the climate. Annual Average Temperature is 55.6°F Avg Percipitation per year is 54.22 inches with a Annual Average Humidity 71.04%. I feel like this limits my options to earthen construction such as adobe or cob but I feel I will no doubt need some sort of insulative layer on the outside of the house. Do you feel foam board is a viable option to wrap the house? I have heard of others doing it over adobe but wondered if this caused any issues with water not being able to transpire. I have even been pondering if imbedding foam board into cob as I built the walls up would work. While neither of these options may be ideal I have a limited budget, a crap load of clay, and already know how to build with cob/adobe so I'm trying to figure out some way to make it work.

Help me wise permies!

It is my understanding that papercrete transpires moisture quite well, and with clay added and only 10% cement. I imagine it would bond well to cob/adobe to form a cheap insulative "skin" that would be much easier to then plaster over with earth than polystyrene foam board would be.

I just haven't been able to find any information about what I am proposing so I turned here...and yes concrete is bad but is sometimes a necessary evil.

Ok so I have been planning/researching/clearing my property for a year now and have around 5k saved to build my home with. I plan to start on it this spring and hope to be finished before our first freeze next year. There is just one problem, I still haven't decided on what material to use. After I attended my first workshop I came away inspired and dead set on using adobe mainly because I was a brick mason for awhile and laying adobe is essentially the same process and therefore felt the most comfortable to me, BUT as I tend to do I am second guessing myself.

My main concern is insulation. Its gets miserably hot here in summer and below freezing in the winter and I just don't see how a huge thermal mass home would be comfortable. I have considered wrapping the home in foam board but don't really want to, so finally my question --- Does anyone have any information regarding applying papercrete over adobe/cob as a insulation wrap? Or thoughts on how it might perform? Or should I just use straw bales instead?

Was wondering if anyone here has experience mixing Vermiculite with cob, and if so what the results were? I happened upon over 200 bags of Vermiculite that was going to be thrown away by a local college because termites had gotten into the storage building. I thought the guy was joking at first...but was really happy to get them!

Anyway, I almost feel like somebody is trying to tell me something as I was planning on building a cob home already, but was a little worried about the low insulation value. Kind of a odd coincidence.

I have read online a few places where they recommend adding Vermiculite to boost cobs R value but I haven't seen any info on someone actually doing it. Does anyone here know what the ratio of Vermiculite/cob should be? Would I replace the sand for Vermiculite, or still add the sand as well?

Think I'm gonna make up some test batches this weekend and see if it affects the strength of the mix, since I plan on my walls being load bearing.

Thanks for any info!

I cant see those pics very well but it looks like your home is earth bermed? Does it stay cool in the summer?

Tyler I live in South Carolina as well, near Greenville, and I feel your pain brother! From the research I have done I think cobb is still a viable building technique in our area, and I plan on building a cobb home near Landrum S.C.

In The Hand Sculpted House they say that for a climate like ours you need to surround the home with fast growing deciduous trees to provide constant shade during the hottest times of the year, Tulip Poplar is what I will be using, which can grow as much as 6 ft per season. If you look at many old homesteads in our area you will see that is exactly what people did back before air conditioning. I think the combination of cobbs breathability and constant summer shade will keep it plenty cool in the summer months, and when the leaves fall I can still reap the benefits of a passive solar design to help heat in the winter.

Keep me updated on how you decide to build, maybe we could swap ideas/problems we have ran into. I hope to start on my cobb home next spring.

Good Luck!

Have my land, read some books, watched youtube vids, now I need some real experience, so if anybody around me needs a weekend workstudy/apprentice or has a cob project they could use help with I'm willing to trade work for knowledge.

I live in the Greenville/Spartanburg area of South Carolina but willing to travel as far as a 1-2 hours away.

Thanks, and I love this forum btw