[GSBN] earthen floors (resilience)

[RT]

In Fri Jan 6 GSBN Digest

Bob Theis wrote:


> we like the stuff beneath our feet to be resilient. Concrete is not. 
> Earth floors are that
[snipped for brevity, see GSBN archives for full text of message and
ensuing thread
http://sustainablesources.com/pipermail/gsbn/2012q1/001861.html ]


I know that a fired clay brick will demonstrate measurable deflection
under load with sufficiently good instrumentation in a lab but if someone
were to smack me in the back of the head with that same clay brick, the
amount of deformation that brick undergoes would do little to alleviate the
pain that my head would feel after being smacked.

Similarly, I do wonder if earthen floors are actually as "resilient" as  
Bob and others espouse.
(Not that I don't believe that they believe them to be so.)

Why ? Well, lemmee tell ya.

I have vague memories of Beel having sent me a sample of an earthen
mix years ago (I forget whether it was straw/clay/sand or
sawdust/clay/sand) and out of curiousity i sawed off a 1" x 1" x # inch
chunk, took it outside and started piling concrete block and bricks onto
it to get an idea of the approximate compression resistance of the sample.

I don't recall the exact weight (somewhere between 75 and 90 lbs if I
recall correctly)  under which the sample started to show signs of failure
but I do remember that its bearing capacity struck me as being impressive.
(I think that I may have sent in a message to the SB-r-Us List on the
matter back then).

Nor do I recall whether the earthen mix was intended for use as a wall
plaster or a flooring material but I think that it would be reasonable to
assume that even if it were a wall plaster mix, the compression resistance
of the sample (ie somewhere between 75 - 90 psi) would at least be equal
to that of one of the Mud Masters' (ie Athena and Beel) earthen floors.

I also think that it's reasonable to assume that the substrate under the
densely-compacted finished surface (ie the drainage layer and "structural"
sub-layers) would be compacted to a density whose compression
resistance would be at least 30 psi.

At those compression resistances, like the
being-smacked-in-the-backside-of-the-head-with-a-brick scenario mentioned
at the outset, I wonder if the oft-mentioned resilience (ie elastic
deformation) of an earthen floor mix, when subjected to the load of a
standing humanid or canid or felid would be of sufficient magnitude to
provide any actual physiological benefit ? (Not that I'm discounting the
the value of any psychological placebo effect).

If the earthen floor surface were so resilient as to deform elastically to  
an appreciable degree under the load imparted by an unshod human foot (ie  
stress = ~60 -80 kPa (6-9 psi))  then I would think that First Worlder  
earthen floors (which clients typically want to have a high-ish degree of  
serviceability) be would show yearsworth of shoe and paw imprints(since  
dogs & cats can't remove their claws at the door)  and permanent  
indentations from heavy furniture and quite possibly (bare) foot imprints  
too, not that those are Bad Things. ie In the same spirit as the  
chrysanthemum-shaped patches on paper shoji "a thousand flowers blooming"  
where little jamfaces are about)

  Me ? All of the floors in my home are either stone, porcelain or wood and  
I am usually barefoot when walking on them and I would say, that for the  
most part, a smile(or a smirk) will be found on my face.  (re: Graeme  
North's comment about smiling faces being exclusive to earthen floors)

I would venture that an argument could be made that the barefoot tactile  
delight one experiences  has more to do with having removed one's shoes or  
perhaps the floor temperature (ie cool during the hot months, warm during  
the cold months) than it does a particular floor material.

But you won't catch me trying to make that argument here. Nosirreebob.

-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada

< A r c h i L o g i c  at  Y a h o o  dot  c a  >
(manually winnow the chaff from my edress if you hit "reply")