Flagstone on new concrete - Flagstone on new concrete

[winona702]

Hi - I'm redoing our patio (brand new concrete slab + thermal bluestone on top), and want to ask your opinion about a few procedures that our mason is following:

(1) Concrete slab: He is curing it in open air (not with water or chemicals). Is this acceptable for a patio concrete base?

(2) Installing flagstone quickly after the concrete base is poured:
Our mason says he typically installs stone the very next day, but I'm asking for at least 14 days for the concrete to cure. Is that enough time? (Do we need a full 28? Is it very bad practice for him to install stones the very next day?)

(3) Adding joints upon flagstone installation: Our mason is very concerned about the idea of stones 'crossing' over joints. As a result, he is waiting until the bluestone will be installed (~2 weeks after the concrete was poured) to cut the joints into the concrete. Googling suggests this is much too late. Is that true? How bad is this? (How quickly could stones crack in this situation?).

Any advice on what to do (what kind of guarantee to ask for against cracking) would be much appreciated.

[seanandruby]

read these pages on rigid bedding N Y
Yes give the concrete time to cure. 48 hours to a week depending on weather conditions. No need for chemical cure but cover if too cold to protect from frost. Cut concrete joints next day, or introduce movement joints. Concrete sub base is very time consuming and if not done correctly can fail. Always best to do a patio with dtp1flexible sub base. Think you use something called whinstone in U S of A if i remember right.

[winona702]

The concrete has already been curing for about 5 days; if the expansion joints are installed next week, is that ok or too late?

[seanandruby]

You just need to cut the concrete joints in and that should do.