Mudding the walls
With the glass in, and the building starting to
be more weather-proof, it was time to decide
how to finish the interior walls. Among the
choices to consider are adobe, stucco,
cement-plaster, "shot crete", or other
commercial plasters. From the beginning, I
wanted earthen walls. They look fantastic
when they are finished. Since we were so far
behind, however, we considered using a
different finish. One that we could pay
someone else to do. We also tried to find
someone locally that works with adobe, but
we were unable to. I'm sure there is someone
here, but we sure couldn't find them. I talked
to many different people about our options but
be more weather-proof, it was time to decide
how to finish the interior walls. Among the
choices to consider are adobe, stucco,
cement-plaster, "shot crete", or other
commercial plasters. From the beginning, I
wanted earthen walls. They look fantastic
when they are finished. Since we were so far
behind, however, we considered using a
different finish. One that we could pay
someone else to do. We also tried to find
someone locally that works with adobe, but
we were unable to. I'm sure there is someone
here, but we sure couldn't find them. I talked
to many different people about our options but
the most convincing argument came from an experienced mud slinger that has done several Earthships.
His comment was something like "PLEASE, don't shot-crete your beautiful Earthship!" So we decided
that although it would take us longer to do, the only prudent choice would be adobe. As previously
mentioned, and on advice from Earthship Biotecture (formally Solar Survival Architecture), we used
cement and one can as our initial pack-out layer. This is to help waterproof the wall and to help lock
His comment was something like "PLEASE, don't shot-crete your beautiful Earthship!" So we decided
that although it would take us longer to do, the only prudent choice would be adobe. As previously
mentioned, and on advice from Earthship Biotecture (formally Solar Survival Architecture), we used
cement and one can as our initial pack-out layer. This is to help waterproof the wall and to help lock
the tires together, although using cement
is not totally necessary. Our second
layer was mud. We just mixed dirt,
sand and unchopped straw and started
filling holes. We purchased really cheap
sand, and fill dirt (since we are building
on a flat piece of land, we didn't have
extra site dirt). The sand had big rocks
and clumps of clay, so we sifted it with
a piece of 1/4" hardware cloth and then
mixed 12 shovel of dirt to 18 of sand
and put 4 big fistfulls of unchopped
straw into the mix. We mixed it by hand
(or by foot) at first which was pretty
neat, but eventually it rubbed our skin
off and we switched to using the cement
mixer. Once the mix was sticky and
is not totally necessary. Our second
layer was mud. We just mixed dirt,
sand and unchopped straw and started
filling holes. We purchased really cheap
sand, and fill dirt (since we are building
on a flat piece of land, we didn't have
extra site dirt). The sand had big rocks
and clumps of clay, so we sifted it with
a piece of 1/4" hardware cloth and then
mixed 12 shovel of dirt to 18 of sand
and put 4 big fistfulls of unchopped
straw into the mix. We mixed it by hand
(or by foot) at first which was pretty
neat, but eventually it rubbed our skin
off and we switched to using the cement
mixer. Once the mix was sticky and
not too wet, we put it onto the walls and stuck two cans in. It is very important to not put too much
mud on at once, but you also don't want to have to do 9 or 10 coats, so it's a fine line. We could have
had a thicker first coat which would have made coats 3 and 4 easier and faster.
mud on at once, but you also don't want to have to do 9 or 10 coats, so it's a fine line. We could have
had a thicker first coat which would have made coats 3 and 4 easier and faster.
On the third coat, we changed the mix,
although I don't remember why. We
started to use much more dirt and much
less sand. As this layer dried it cracked,
not bad enough to be redone, but bad
enough to tell us we'd screwed up! We
switched back to the mostly sand recipe
and there was no more cracking.
Another lesson that we've learned: all
along the way we poked holes into the
wet mud with our fingers. During our
last work party a few people skipped this
step. As a result, the next layer of mud
didn't stick to the previous one. There
were several places where the mud was
loose and pulling away from the wall.
We pulled these off, drilled holes into the
previous layer and mudded them again.
Layer 4 is hopefully our last coat before
our true scratch coats. We've chopped
the straw and added a little more sand to
the mix. This time we've covered the
electrical conduit and only a small bit of
the tires poke out. After this coat, I
anticipate one partial coat to fill in areas
that are still recessed (particularly around
the circumfrence of the cistern walls
inside; because they curve to the outside,
the spaces between the tires are much
larger, which requires more coats of
mud), and then we can work on scratch
coat(s) and the finish coat.
although I don't remember why. We
started to use much more dirt and much
less sand. As this layer dried it cracked,
not bad enough to be redone, but bad
enough to tell us we'd screwed up! We
switched back to the mostly sand recipe
and there was no more cracking.
Another lesson that we've learned: all
along the way we poked holes into the
wet mud with our fingers. During our
last work party a few people skipped this
step. As a result, the next layer of mud
didn't stick to the previous one. There
were several places where the mud was
loose and pulling away from the wall.
We pulled these off, drilled holes into the
previous layer and mudded them again.
Layer 4 is hopefully our last coat before
our true scratch coats. We've chopped
the straw and added a little more sand to
the mix. This time we've covered the
electrical conduit and only a small bit of
the tires poke out. After this coat, I
anticipate one partial coat to fill in areas
that are still recessed (particularly around
the circumfrence of the cistern walls
inside; because they curve to the outside,
the spaces between the tires are much
larger, which requires more coats of
mud), and then we can work on scratch
coat(s) and the finish coat.
I am VERY glad that we chose to use adobe. It is fun to work with, it's pretty easy and I think the results
are going to be amazing. Most people probably don't realize how hard adobe is once it's dried. Well....it's
REALLY hard! I tested some spots with a hammer and I did very little damage, no more than any other wall
surface. In my opinion adobe is the way to go!
are going to be amazing. Most people probably don't realize how hard adobe is once it's dried. Well....it's
REALLY hard! I tested some spots with a hammer and I did very little damage, no more than any other wall
surface. In my opinion adobe is the way to go!
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