Here is a picture trying to show the consistency of the tufa mix. It's not crumbly at all. You can see that its wet, but not so wet that water drips off. When squeezed it sticks together very easily.
The mix consists of 1 part Portland Cement, 1-1/2 parts Perlite, 1-1/2 parts Peat and just enough water to make solid lump when squeezed.
