Sounds sturdy and I'll bet it looks cool and develops a nice patina. 
But I have one question.  2x4 has rounded corners.  That means that
there will be gaps where the corners of the blocks meet.  These gaps are
going to fill with dust.  Maybe it won't matter.  Maybe the dust will
get packed down in the gaps and just increase the stability like sand
between paving stones.  But it seems that it might make dust control in
the shop a tougher job.  I am envisioning that every pass of a broom
draws up more dust out of the gaps, making it an endless job.  And you
had better not drop a ball bearing.  And if they don't fill with dust,
won't the unsupported wood split off into the gap under the pressure of
foot traffic or the planing of the floor?    

I suppose you could plane the faces of the 2x4 to get sharp corners
before you cut them and lay the blocks or maybe daub some putty in the
gaps before you plane the floor.

What do y'all think?

Blake       

>>> Gary Curtis  04/25/2005 6:02:37 PM >>>
My architect friend reviewed my shop plans today. He had one
suggestion. The
floor. He recently used the following concept for the remodel of a
commercial machine shop.

He took ordinary 2x4s. Cut the timber into 2-inch blocks. The blocks
were
laid down right over the concrete slab, with only  a 6 mil plastic
moisture
barrier. 

The blocks are laid down as a parquet, end down, so the top view is a
3.5x2
inch matrix of wood. The depth is also 2". There is no need for
sleepers
along the side, only some shimming to keep the assembly tightly knit.
No
pressure treated lumber, no glue, no waves, no buckling or sagging
(that
would be waves), no cold feet, no collapsing under the weight of heavy
machinery.

Nothing short of a nuclear reactor vessel is going to crush a 2x4
cross-section of wood. Pressure treated wood might help the longevity.

I asked how one would true the surface of such a floor once installed.
He
said the finish carpenter on his job used a jointer plane. Can you
believe
it? A hand plane. The big machinery was simply rolled in smoothly on
dollies
and a forklift. Riggers did that part of it.

It just occurred to me that this would be ideal for a shop with a
sloped
subfloor. Just taper the cuts of 2x4 blocks.

Facing the awful alternative of the Buckminster Fuller appearance of
OSB
with full varnish coating, damned if I'm not going to try this when I
build
my new shop. This is my kind of high tech. Any thoughts out there in
shop-land?

Gary Curtis

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