latex slc ufh and hardi

[merit]

reading through all the threads on slc as appossed to addy for ufh,
advise needed,
can i slc over the hardi without priming?
can i slc over ply if fixed as reccommended,this stuck in my mind from years ago as a no no
but i suppose products develop
ive been told from the local supplier the weber flexi adhesive can be used on 9mm ply over boarded on floor boards/chipboard,could the same be said of the weber slc?
i tend to addy the ufh as was first directed, but the mat cant always be layed as im mixing up!lol
all recommendations on best products for the above greatly appriceated

all advise on the above

[Sir Ramic]

Firstly always follow makers of SLC instructions. Some say prime boards and some may not.
Usually I follow the saying "if in doubt , Prime" A call to technical depts are worthwhile.
Yes you can SLC over timber, Weber, BAL, Mapei etc all now have products that are capable. I still wouldnt use 9mm ply as its below BS , 15mm is minimum.
I am sure that Weber state that when going over timber they say a minimum depth of SLC, again not 100% sure but I think it was 10mm of SLC.
As a recomendation of a product, Mapei Ultraplan Renovation screed is my favourite at the moment.