SB: Re: Smelly earthen floor (OT)

[Barbara Roemer <barbandg@onemain.com>]

Many thanks to those on this list, including John, Royce, Rob, John, Kenn,
and others, and those on the cob list who responded regarding our smelly
floor.  I received lots of good advice, but perhaps of most value is the
reminder that it's useful to slow down, consider conditions attendant to the
problem, and look for the less obvious.  We'll sprinkle on lime, leave the
door open, watch the mold to see if the area increases, work on the
foundation drainage, and bank on better weather.  (After an 80 degree week,
we had 6 inches of snow quite suddenly, though temps are rising to normal
daytime 50's now.)  Perhaps of interest is some sketchy information I
received from Darel Henman on the cob list.

I thought Darel had mentioned that Japanese builders intentionally let straw
ferment in their floors.  Though the chemistry of it still doesn't make
sense to me, he explained further the process of gradually adding straw to
the already fermenting straw in cob for use on walls:

"They don't put it in floors.

They use it for daubbing (cob) onto wattle walls.  Why they do this is
because they feel that the lignin and pentose come out of the staw
fibres and adds more stickiness to the mix and results in a harder
resulting wall.   Note also that they don't do this to all of the
straw.   They also feel that keeping the soil wet for a long time (up to
a year or more for temples), three months average, but at minimum two
weeks, is to let the iron in the soil oxydize and to let the organics in
the soil float to the top and not used.   For the long soaking period
they add the straw in not all at once in several additions.   The reason
for this is said to be that the most fermented straws still have small
fibres that grab the smaller clay particles and bind them together, and
the lesser fermented and larger straw fibres then bind these together
and so on until the newest straw added a day or two before application
is then to hold all of the largest clumps together.

The Japanese mud masoners also say its important for the straw and soil
to get used to each other: they begin to meld together and the soil
changes color after soaking for three weeks.  The optimal length of time
for soaking the soil prior to use depends on the temperatures, but one
rule of thumb is at least until the soil changes color and black mold
forms on it (this is the oxidized iron I think or rust from it).

For floors in Japan, from what I read, I hope to see some the end of
this month, the (tataki) or tampered floors consisted of
    1. a granite soil,
    2. lime, 
    3. water, ( with optional salt or Magnesium-chloride left over from
salt making)
  
 These ingrediengs where mixed in a semi-dry mix and then tamped/rammed
down to about 50-67% of the before packed level.  This technique was
used for entry and kitchen floors and sewer lines. and runs around the
house and was in use until about 70 or 80 years ago in the country side.

 They used this for some fence walls as well.  Sometimes they would put
a vegetable oil in it to aid in water protection, but one has to not
over due the oil part.

 I was just using their wall daub mixtures as an example of the smell of
fermenting rice straws."



I'd love to hear more on the daub and floor mixes from other Japanese
builders.  Again, many thanks for the varied perspectives.

Barbara
Nevada City, CA


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