Flex adhesive and hardibacker

[grayless]

Hi
Has anyone used the Bal single part fast flex with hardibacker for floor tiles and if so do you need a primer? I can see it is recomended for use with Fibre reinforced cement boards and lightweight tile backer boards, but i'm not sure hardibacker is either of these. Also i cant find what coverage you get from the 12.5kg bag.
I have always used Bal flex ( two part )both under the hardibacker onto floor boards and then under the tiles, as the only time i used a cheaper alternative the tiles moved, i am hoping the Bal single part fast flex will work as it would be cheaper.
Thanks

 

[DHTiling]

No need to prime...

I don't have issues with a standard S1 adhesive as long as the floor is strong enough and prepped ok...but S2 single part will be fine..

 

[grayless]

I am probably being thick but i can't find out on the Bal web site if single part fast flex is s1 or s2, i asume for your message it is s2.
thanks for your reply. The adhesive i used when it failed to bond for me was a Travis Perkins own and i even tried it again ( different bag ) on a primed concrete floor and found it did not bond very well, so i avoid it now.
Thanks again

 

[grumpygrouter]

Fast flex in both it's derivatives exceeds S2 spec.