with Earthen Plasters:
My house has earthen plasters (clay, straw, and water,
covered with white glue) inside and outside. For 9 of
the 10 years I have lived here, the plasters have had
no other covering, but just last year, I coated the
exterior plasters with a lime finish. It is these thick
earthen plasters on both sides of the straw, that make
the house very stable and solid - well along with other
things. I'll discuss what all that is and how it holds
earthen plasters on the outside of the house
with made with high-clay soil that I bought from the
Pasqua Yaqui tribe and is generally used for adobe houses.
These plasters are made of soil, chopped straw, and
water. We chopped the straw in a
leaf mulcher. I have a 7-foot porch around the house
to protect them from the rain, which they do need. I
think there is some illusion that using prickly pear
gel in the water will make them waterproof, but this
is not true. If you are wondering if your plasters will
hold up in a rainstorm, turn the hose on them full-blast
and see what happens. Adobe houses add asphalt emulsion
to this mixture to make it more waterproof. I have never
done that, so I can't comment on that. I did see some
tests and it looked like it really works, though. I
did get some pitting on my plasters after our summer
thunderstorms for the first few years and then the storms
subsided and I had no issues for the last six or seven
years. Coating the lower part of my walls with stucco
waterproofing (it's clear) helped them resist the thunderstorms.
I coated them with lime because the birds were pecking
holes in them. I'll discuss the lime coat further down
reasons to use earthen plasters instead of stucco are:
earth will let the straw breathe, so if it gets damp,
it can dry out. To apply these plasters, you don't need
to coat the house with wire - you can just damped the
straw with clay/water and then apply the plasters with
your hands. So, it is less expensive than stucco because
you aren't using expensive concrete and you are doing
it by hand. The problem is that you will most likely
have to do this by hand - no general contractors that
I have met understand earthen plasters. I think you
might be able to hire an expert and fly them out, but
I have no idea what this would cost - a lot, I think.
I think earthen plasters should be done by hand and
become an expression of art by the owner. You can scult
them, color them, embed shells, glass pieces, glass
bottles, or anything else you feel like embedding. If
you don't like what you did, you can scrape it off and
start again. It becomes a wonderful, fun hobby and is
interior plasters are the same as the exterior,
with a finish coat. This finish coat is comprised of
white powdered clay from a pottery store (costs about
$10 for 50 lbs), a little gold oxide powder to remove
the gray color - you can use any color you want, powdered
clay comes in many colors - or once I used some clay
that I found in the ground in New Mexico - this is mixed
with only water and when it is dried, I coat it with
white glue/water. Lowes carries gallons of white glue.
This is far less expensive than paint and much more
beautiful. Once you have applied the clay, before it
dries, you can embed whatever you want, or shape it
into window and door frames. I also made a headboard
for my bed from earthen plasters.
of the interior plasters: They also let the walls
breathe and dry out if they get damp, they allow fresh
air to filter through the walls, as long as the exterior
is earthen also. They are a little uneven, so they are
acoustically very soft - a good thing in a small house.
They are chemical-free. They make the house feel like
a home with their handmade unevenness and natural, earthy
tones. It is not the straw in the wall that stands out
in my home, but the plasters.
I began coating the interior plasters with lime paint,
also and that is because I found that the clay darkens
over the year. I think it's a natural oxidizing process.
Lime does not and is again a little more durable than
clay. But I like the clay better, actually, I'm beginning
to think of retiring some day (I'm 60 now) and thinking
of renting out the house when I do, so I want to make
things a little more general-public friendly. Clay plasters
are softer and you can't scrub them if someone throws
ketchup on them. When they are coated with white glue,
however, you can wipe them down. The lime paint is brighter,
but it does not have the color inflections of clay.
Here is a photo of the difference in the walls:
plasters: On the outside, I roughed up the surface
of the clay plasters with a wire brush, then troweled
on a mixture of powdered S lime (from home improvement
stores), #60 silica sand (from sand-blasting supply
co), water and ferrous sulfate fertilizer for color.
The ferrous-sulfate fertilizer is from a wholesale garden
supply center. All the ingredients are inexpensive.
The result looks like peach suede and I'm very happy
with it. Here is a link to a photo with the new exterior
is more durable than earthen plasters, but it also lets
the walls breathe. On the inside, I just made a lime
paint - lime, ferrous sulfate, water - no sand - and
painted it on with a paint brush. It doesn't have all
the nuances of the exterior plaster - it's much more
like regular paint - but it's bright and durable. It
still has more of a natural color and highlight than
paint, I think. I also coat this with white glue and
water when I'm finished to make it more scrubbable,
if needed. I guess I could mix the glue into the paint,
too. I might try that.
that answers some questions.
a great day and be kind!