Cob Re: Plastering

[Patrick Newberry]

There was a bit of a discussion going on in the strawbale list about 
earth plasters. Since I've started plastering NOW. I thought I check 
if this subject has any interest in the cob world.
On the outside of my house I am  using earth plaster for those areas 
that have protection from the rain and stabilized earth plaster (20 % 
cement) for those areas that do not have protection from the rain. 
Inside I going with earth plaster. 

(by the way good link on lime:
< http://www.genlime.com >
 
This was a reply:

> 
> For strawbale, I would use a mix of 1 part cement, 1 part lime, and
> 5-6 parts sand for a strong base over sb.  Over a loadbearing wall
> which does not require strength, I'd use 1 part cement, 3 parts
> lime, 10-12 parts sand.  The finish coat would be the same in both
> cases for interior work, and the exterior coat would be higher in
> cement, depending on exposure. BUT, I would love to hear what other
> people use, since my experience is basically limited to
> brickwork/old stone, etc.

The orginal "challenge" for lime plaster (per Tom) was WITHOUT 
cement.

I too have been attempting to do some earth  plaster. The first I
attempt  was with  earth (clay and sand and straw)only. This is for
the interior of my house. On the outside I have a stabizied earth
plaster as in CEMENT. Anyway back to the inside... I mean it was ok
but if you were to brush up against it with a nice white shirt it
would be noticed by whom ever washes cloths. Plus I think it would add
a bit of dust to the interior of the house.

I added some lime, the type they use for some kind of water 
treatment.

Going to the building store there was not many options.
the small test bricks I made with the stuff I did notice a 
difference. That is using the rub off on the white shirt test there
would be improvement.

I am thinking of adding a small amount of cement. 
but I am thinking of other options as well. 

I've heard cactus juice boiled and added to the final coat works
well.I have a source near here and will attempt to use that method.
That requires some boiling of the catuses but I think you only need to
deal with it on the final coat. 

I've wondered about linseed oil since it's used for  earthen floors
but for some reason I've never heard of it being used for walls? Not
sure why. Also the the linseed oil and wax mixture (also used for
floors) sounded interesting.

I've already started plastering but I will be plastering for til the
middle  of next summer. So I plan on trying several different type of
plaster between now and then. 

Even though it can get up the the high 50's or low 60's (F) here in
Georgia, plastering when it's cool, just about freezes one's hands.
(Well it does get down into the 30's at night)


I'm off to visit relative for the week and hope this is a wonderful
season for everyone. May the new year start and all your building
dreams be fulfilled. May your bales be tight and and you cob bricks
hard and may it never rain till your finished with that roof. 

Love and Light 
Pat.
http://www.gnat.net/~goshawk