Install flagstone on top of concrete.
Latest project is to lay flagstone on top of the concrete landing at the top of the steps. It is a 4 x 8 landing. I plan to use regular portland cement, loosely mixed then push the pieces in it and let dry. I am not certain how to do the 'grout' part. Should that be cement too? I have seen some finished projects that seem to have a type of gray rubbery type of grout between the peices. Anyone know of the best way to do this?