It wasnt primed at all before the first coat of 1200. And when I say pinholes all over the place I mean thousands of them over the 25m2 floor. Anyway, the contractor assured me the F77 would cover them. BUT, it did not. It looked like every pinhole in the 1200 became even worse after the F77. The contractor said it was fine and was keen to prove it by sweeping a moisture meter over the F77. Needless to say I was not impressed by his attitude, so I pointed out the F77 technical data sheet supplied in his 14kg kit where it says "if not pinhole free, apply a second layer". So, he begrudgingly agreed and went off in a huff. Yesterday he returned and applied the second F77, not easy to apply evenly a glossy black fluid on a glossy black surface! , I also "reminded" him that the TDS required the F77 coat " to be run up the walls up to the DPC" in one continuous sheet.....something he had not done on the first F77 layer. I was amazed when he said he had never done that and "I do floors, not walls". Nonetheless, he begrudgingly complied. This morning the result of F77 #2 was much improved, from thousands of pinholes to a few dozen. He assured me the resulting damp proof layer was "one hundred percent". He applied the top 1200 this morning and the result looks OK, not perfect.
However, he has run the top 1200 onto the bottom 1200 and even the original floor in places.......which means the top 1200 layer is on contact with the "damp" floor bypassing the F77 DPM completely. I despair. But I can easily fix that with a little grinding back.
And before you think this was some rogue tradesmen, or cheap job. No, he owns the flooring specialist company in our town with flashy showroom, and he kept mentioning his 15 years experience and premium service. The bottom line is that the contractor should have tested the absorbency of my subfloor and PRIMED before the first Stopgap 1200 layer. My advice to the trade is do not insult the customer's intelligence especially when TDS are easily downloaded.