just thought id up date, finally got the go ahead from lewis the bal rep who ,moisture tested the anhydrite floor. after 35 days finally got moisture down to 1.5 so gave us the good to go so we started yesterday with a dark gray riven limestone 600 x 900x 20mm thick 220 mtrs to lay.
1st thing about the job no sanding so after a sweep and vacume started to roll out the flex bone matting was so easy to lay and two days in we have 60 mtrs down.
i would like to thank lewis from bal for his advice and for carrying out the carbide moisture test.was worried it would sound hollow when walking on but it sounds just like any other decoupling mat floor ive done. will defo use again.