sunshelf

My PB missed adding the sun shelf to be 9”, so he’s adding the form and will pour concrete with rebar. How long will a tanning ledge of 6”, size of 12’x9’ take to cure for plaster? I’ve read 7-10Days to 28. My Pb says he can plaster very soon after but I’m concerned about the long term effects.

Hello all I’m considering placing Pollywood Adirondack chairs which are very heavy on my Diamond Brite plaster. It’s been two weeks since water was added. Should I have a concern about the weight of the chairs with the plaster fully cured? Thanks Rod