I have a wood column I'd like to mesh and mortar into a rock column.

I was able to do the same mortar design another part of the house
applying a top coat of a techitured paster (silica) with tit like
ridges i then sanded down. The effect was a coral rock like look that
fools the eye.


Problem is I need to lay the mortar extra think as the column is not
that thick this time and have it bulge in places 2 to 3 inches thick
from the steal mesh.

I plan to use a mortar with some pvc additive that's suppose to be
extra resistant to cracking. I've tried it before and it's extra hard
and durable but does not look good as the final coat. Hence the need
for the silica plaster for texturing. However, i'm not sure I can
laying 3 inches thick alone.

I've heard of people adding perllite and peat moss to mortar or
concrete so that it can be molded into thick objects. Is this a good
technique? Advisable?

Any other suggestions.