Earth/lime plaster

[peternap]

Has anyone got the recipe for earth and lime plaster.
The best I can come up with is sand, clay, a "Bit" of wheat paste and lime.

I have no idea what proportions.

[MaineRhino]

In the book "Building Green" they described their earth/lime plaster mix as 4:1:1:1 or 6:1:1:1 sand/lime/clay/straw, with best results using soaked straw.

It's a great book with loads of pictures and various building methods.

Here is a chart of the plaster mixes they used.

[peternap]

Thanks MR!

[glenn kangiser]

Looks like a good formula.  Most decent earth building uses 70% sand and 30 % clay average .. plus the rest stuff to be a plaster.  I made one similar that is holding up well about 7 years later.

[peternap]

I'm adding a room and want to try a structural wall of stray bales.

[Onkeludo2]

Having worked for a day (not much experience) on one of those structures, I have only a few suggestions:

Make sure your bales are TIGHT
Pin the living bejesus out of them with your rebar/bamboo/long straight sticks
Seriously consider the concrete bond-beam to top the walls...with a ton of rebar in it

I loved that work and still dream of building with it, but it is lots of back-breaking toil.  The foundation details can be difficult as well.

Mike

[peternap]

Thanks Mike!
I'm working on the foundation now and it is unusual. A very wide beam foundation strung between posts on 6' centers.

What is a concrete bond beam? Most I've seen are chipboard and 2x6 beams acting as a cap.

[Onkeludo2]

The bond beam is where you create a continuous concrete monolith (think about a 6" deep concrete slab all the way around the top of your bales) for your top plate.  The easiest way to do it is to "clamp" a piece of of OSB on either side of the bale using pieces of all-thread through the bale and braces of scrap 2 x 4 on top of the OSB forms...this was so much easier to do than explain.

It really uses less concrete than you think and the stakes sticking up from the bales ties it all together.  I am told there are a million ways to do structural bale and the hardest part is usually tying the room to the walls to the foundation.

Mike