Aaron Yarbrough

Welcome Wade! Yes, different, bot-free and loving it.

Danbi Bigras wrote:If a hit an hempcrete ( without plaster ) wall with my hand, it's very hard and nothing happen, but " i think " that if i do that on LSC wall , my hand will go " in the wall ", Am i right ??

No, if well packed, once light clay straw dries it is very solid.

Danbi Bigras wrote:
It would be interesting to have a comment from somebody who used both,  but R value seems to be difficult to establish. Not just a matter of R but also the heating system, the design of the house, etc..

Yes, there are a lot of factors and I don't think you can make a direct comparison between light clay straw or hempcrete  and conventional insulation but of the former have substantially more mass then conventional insulation which I'm sure has an effect but isn't part of the R-value measurement.

Danbi Bigras wrote:
By the way, what do you think of 1500 ft2 of outside wall alone.....?   : )  I'm not expecting to do that in one season if we consider how many weeks it takes to dry, so it's ready before winter.
Mmmmm you know what, maybe it's better if you don't tell me !!  Hahaha

I think you know the answer to this one. I recommend wearing gloves and getting a few audio books.

Hey Danbi,

Welcome to Permies! Yes, it will work although I've heard light clay straw has a lower R-value (1.5) then hempcrete (2.0) although I've also heard that light clay straw has an R-value between 1-5 & 2.0. I have a timber frame cabin infilled with light clay straw built in a similar fashion.

Hey Pia,

Welcome to Permies! If the wood panel finish is smooth plaster won't adhere well to it. You could do a lath and plaster finish by fastening the laths directly over the wood panels. Just make sure you anchor the laths to studs. The downside is your walls will end up about an inch thicker. If you removed the wood panels I've heard you can apply sand and glue mixture to sheetrock to provide a mechanical key for plaster but never tried it myself.  

I haven't used toilet paper but I have used shredded paper for the fiber in my natural plasters. For the base coat I'll use finely chopped straw and then for the finish coat I'll use shredded paper rom sometimes no fiber at all if its a really thin skim coat. I'm a big fan of using lime as a binder. It doesn't seem to dust off as much as clay based plasters and is harder wearing. To tint the lime plaster I'll used iron oxide powder but you can probably use a mix of lime and the clay from your site.

Straw bale is probably the fastest and best suited for your (very cold) climate. Rammed earth can be fast too but provides very little insulation. Hempcrete and light clay straw are slower than straw bale because the walls have to be packed and allowed to dry out before plastering. Cob and earthbag are probably the slowest.

If you've already built a conventional house straw bale, hempcrete and light clay straw are fairly easy transitions.

Regarding the sandy soil, it probably won't be an issue unless the ground is all sand to below frost depth.
 

 

Welcome to Permies Dave!

tracy sane wrote:what sort of protective material should be placed between lime mortar and wood surfaces? I was considering coating wood edges that would otherwise touch lime mortar with roof pitch that wouldn't show.  any advice appreciated.

None. Lime mortar will protect the wood since it is vapor permeable so it won't trap moisture that would cause the wood to rot. Lime is also alkaline which gives makes it inherently mold and mildew resistant.  

I agree with Cristobal. With adobe bricks I would build the wall around the outside of the posts (pillars) and then cob the gap between the top of the wall and the roof.

You could also you movable forms or T-Bricks as they are called in this thread if you wanted to integrate the posts into the wall system. I would use screws for the corner forms since they would have to be partially disassembled to fit around the posts. See a sketch of a partially assembled walls below.  You'll need to partially drive a lot of screw/nails into the posts to provide a mechanical key for the cob.

You beat me to it. I just saw the video and was going to post about it on Permies.

Rebekah Harmon wrote:Cob, cob, and more cob. My fingers are raw. Two more days of cob until the finish layer.

Cob is no fun in the cold. Looks like you're making good progress.