Evening all ... I'm in the process of decorating our lounge & it's nearly time to think about the flooring , think we're going with real wood but I want to get the preparation correct . It's about 20 square metres in total & currently , vinyl tiles that I don't want to take up as stuck well & sound , around the edge there's a few loose ones that I've removed & another area where an old fireplace existed there's a bit of old self levelling compound that's been used , no major differences in levels I'd say Max +\-6mm over the floor area , just want to use some self levelling to get it spot on before laying the underlay then the wood flooring Screw fix no nonsense self levelling seems to get good reviews but does mention a primer but no suggestion of what to use , any suggestions please ? also any idea how much gear that I'd need to do 20 square metres say 5/6 mm deep all over please ?