Wet Flagstone install question?

[Green Elegance]

Hello and good day everyone,
I have a customer who wants an extenstion to thier existing patio, which is a poured concrete slab of 14x14..........they "want" approx 500 extra sq ft of an extension. They want concrete, but I suggested possibly flagstone(wet install) Does anyone know what I should charge per sqft just for the labor, and if there is anyway to install this flagstone withoug having to pour a concrete slab and still get a solid result?

(keep in mind the customer is penny pinching as alot of them do)

Thank you,
-Green Elegance

[hortiscape]

Flagstone can be installed on compacted gravel and sand, but you cannot mortar the seams. We have deep frost in vermont and dry flagstone bases work better for us because the poured concrete pads need more reiforcement and are more costly. Also we use large pieces of flag 4"-6"thick and 3', 4', 6', and 8' ft sq. pieces.' This keeps the movement over time to a minimum. This flagstone is all blasted and removed raw, there is no standard thickness. every piece needs to be set by lowering or raising that micro-grade for that particular piece. In my opinion only large, thick flagstone should be used in dry flagstone applications.

[Green Elegance]

I am thinking a Dry Install will have to do for this project as I do not want to have any issues in workmanship for not pouring a slab first. The only think I hate here in TX is that there is not many options for dry install fillers. We have mostly one color of dec. granite(caramel) and what do I do if a customer wants a grey flagstone?
I personally use 2.5in thick flag on most of my dry apps, using 2-3 inch dec granite, 1 inch washed fill sand..........any additional suggestions for a dry install?

Thanks,