Roy Smith wrote: Have you actually tried this? I'd be worried that the
sheetrock wasn't strong enough to support the pressure of the sand pushing
out from the inside of the wall.
Actually, I have not. And I considered your concern, so I did the following
calculation: Dry sand weights about 100 lb/cu ft, which calculates out to
about .7 psi per foot of depth, or about 5 1/2 psi for an eight-foot high
wall. That doesn't seem like a lot to me-- since the saving to be had by
using sand are considerable, compared to all the other ideas suggested, I
have two ideas. Nail sheetrock to two 2x4's to make a simulated wall
section 16" on centers. Stand it up and pour it full of sand. See what
happens. If you want to reduce the bursting tendency of sand, you could mix
a little Portland cement and water with it--not to make real mortar--just to
make it set up to a crusty concoction, that would hold up its own weight.
Then, pour the walls in stages, allowing the stuff to set between pours, so
you never have the full hydrostatic pressure of eight feet of sand against
the sheet rock. This wall would behave the same as a "tilt-up," and would
I figure that a 10 foot wall would need about one yard of sand. Think of
the savings, compared to staggered studs, lead sheeting, or special spacers,
etc., plus all the labor to build these systems.