LSC wall structure with timber frame

Hello !
I made my house ( now sold ) with timber frame and 12 inches hempcrete. The wall is 8x8 structure ( with 2 inches visible inside ) , 2x4 wall on the outside and 3 inches with nothing ( I mean 3" with only hempcrete ) . The formwork was 3" from de 2x4.
Will the same thing work with LSC ?
I saw an old post ( 5 years ago ) about that , but with no real end to the story.
I think LSC should wrap up well the 8X8 with 3", and stay.
What do you think ?
Plaster will be lime and sand.
Tank you !

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.

Ho HI !!  Yeah i saw many of your videos on YT. You've done many things you and your family ! Tank you to share your experience.

OK. Tank you.


Mmmm.. I'm surprised too read that.  I would say that LSC is better that hemp. Hempcrete is a lot more wet, with less air and more dense. Like the typical "ball test " you can do with the mix to know if it's a good mix.
And the fiber is cut fine to be able to pack it very tight in bags, like wood shave bedding bags.
But i've never tried LSC,, So.
I have Lydia Doleman book.
Like hempcrete, it's possible to make a too wet mix and loose R value, but from what i saw in videos and pictures, i'm more concerned about having a "too soft" wall that doesn't  hold well together compare to hemp.
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 ??

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..

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

Tanks again !
aniel

Ho!
Also. I made my house 7 years ago.
Now, it's waaaaay  too much expensive to built with hempcrete !

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.

I just did an interior wall using a light earth mixture with wood shavings instead of straw. There's also chunks of biochar in the mass. You do have to be careful about how wet and clay-rich the mix is as you put it into the forms, and gentle tamping is a must. it's been four weeks since we did the work and it still has more drying to do (100 mm thickness, and we've had weeks of unusually cool and wet weather), but the infill is very firm even in the sections where we "got it right" and there are lots of air pockets.

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

All right ! Happy to read that.

Tanks !