Cob: Re: subfloor for adobe floor

[Keith Breuker]

Hello Listers,

Here's my two bits on adobe sub floor:

My experience agrees with everything Bill Steen said.  

I constructed a large thermal mass for my sub floor.  It consists of 100
cubic yards of compacted road gravel containing clay, sand and gravel. 
The subfloor was insulated around the perimeter with 18 inches of
styrofoam peanuts to a depth of 48 inches.  No insulation underneath the
subfloor. 

The sub floor was leveled to 3 inches from final floor level.  The
earthen floor was placed in one pour of 3 inches.  The mix was 3 parts
gravel, 1 part clay, 1 part sand and just enough water to make it
workable.  We made 3 inch screed boards and poured sections three feet
wide.  Then we moved the board thirty six inches and did another
section.  This mix held its shape when the board was removed.  We
applied a finish slip coat, then Natural Choice penetrating oil #5.

I'm going for a seasonal amount of thermal storage.  So far this summer
(we moved in May 1) it has been very comfortable even in the above
normal heat and humidity we've had.  Mid 90 degree temperatures with the
interior temperatue never above 75 and usually 72 F.

The real test will be this winter.  Last February, during construction,
no heat was needed when the sun was out.


-- 
Keith Breuker - Engineer

Straw Bale Owner/Builder
Flyfishing Author
Beulah, Michigan  USA
616 882-5648   flyfisherkb at centuryinter.net