Unpopular opinion: I used to think all floor leveler was basically the same until a job in Tempe

I was mixing a bag of Ardex K 15 for a bathroom remodel last Tuesday and the homeowner's dad, a retired union guy, asked why I wasn't using a primer first. He showed me a picture on his phone of a failed pour from five years ago where they skipped that step, and the whole thing delaminated. Now I'm rethinking every quick patch job I've ever done. Do you guys ALWAYS use a primer with self-leveler, or just on concrete?

3 comments

3 Comments

umabailey2mo ago

That Tempe story is a perfect example. I learned the hard way on a slab in Mesa about ten years back. The primer is non-negotiable for a good bond, even on clean concrete.

miles2772mo ago

Yeah, that "non-negotiable" part from @umabailey is dead on. I skipped primer once on a garage floor that looked totally clean, just dusty. Swept it real good, thought it was fine. Six months later I'm picking up whole tiles where the car tires sat. The dust bonds to the primer, not your adhesive. Now I even etch old slabs with acid first, then prime. It's just not worth doing the job twice.

brookep621mo agoMost Upvoted

How many times do we gotta learn this? @umabailey is right, clean concrete can still have a skin that blocks the glue. That primer step is just part of the job now, no way around it.