Question

Do you need to seal concrete before using floor Leveling compound?

Answer 1

You can use the leveling compound on your concrete without sealing it first but you'd get much better results with the leveling compound if you do seal the concrete first and then apply the leveling compound after sealing the concrete.

I've applied leveling compound before without sealing the concrete and it worked but I wished I had sealed the concrete first and then applied the leveling compound.