Hey all, Just curious on what your take is on Priming the slab before laying?? I was doing it for a while and never had any problems but was recently told that it shouldn't be used as in some cases the the tiles have become drummy.. So now I'm back to a quick sponge down before each row?? Whats you opinions please

welcome to the forum im from the old school prime everything make sure primer is acrylic (not pva) if you dont prime you could always use that as the reason tiles have gone drummy

clean and prime you will reduce suction.also reason tiles can be drummy adhesive drying out to quick or dips in floor .

Always have just wiped the floor down. Never had a call back for drummy tiles in 28 years.

In most case you're actually better off washing the floor with a wet sponge. Acrylic primers need to penetrate, if the substrate is too dense you're effectively putting on a layer of cling wrap ---> drummy tiles.

Originally Posted by FrankM

In most case you're actually better off washing the floor with a wet sponge. Acrylic primers need to penetrate, if the substrate is too dense you're effectively putting on a layer of cling wrap ---> drummy tiles.

very true.
have seen this with bad surface prep, primer glazing off,
we grind common floors to remove (latance) please correct me for bad spelling, and use good old h20 to prime.

In my years of experience I found that tiles stick better if the floor is not primed. If you have ever ripped up a tile a week later on a primed surface the tile will pop up quite easy but if unprimed normally will come off in small pieces and rip hunks of concrete up as well. If the floor if powdery (normally due to a rain on the slab when it was poured ) priming is necessary. Also if it is a hot day priming will give the adhesive a bit more drying time. Tiles will adhere properly if the floor is clean and free of dust generally priming is not necessary.

Never primed a slab . Ever.

Good prep is all thats needed. "hungry" concrete can benefit from some wetting down first but overall I agree with the rest, a good sponging down to remove any dust/dirt is enough.

Interestingly, for an adhesive to comply with the new adhesive standard, they are all tested on unprimed surfaces. Although, concrete is one thing, if your going to use a cement based adhesive on FC wallboard or FC ceramic tile underlay, priming is a really good idea.

so in general its best to prime is what im reading from this post but its not needed right