Does sealer have to be applied and sreening need to be done before applying polyurethane?

What are you trying to do???

Sealers, are not moisture blockers.

Thanks for response. My friend who does floor refinishing told me tjat sealers are moistuer blockers and should be put on at some stage of reninishing and then screened with 80 grit and then final coat of polyurethane applied

Ok...OK... Duh? I had a brain fart!!



I'm thinking concrete sealer before gluedown installation, and we are in the sand & finish forum!! And to boot, you explained it pretty well.. OK, I was tired... That's my story and I'm sticking with it!



A sealer coat before poly is a good idea. Screen and tacking is always a good practice, to get a tooth, unless your hot coating.

Gary has a better handle on finish issues. Maybe he can assist you.

Sealers are not water proofers. Their function is varied. Some floor finishes , like oil-modified polyurethanes, are self-sealing and need no separate sealer. Other floor finishes, like certain water-based finishes, do need a separate and special sealer. So, to answer your question, whether or not you need a "sealer" before applying floor finishes, is it depends on the finish you are using. I suggest you select the finish and then determine if the manufacturer of that finish requires a certain separate sealer to be applied first.

Very helpful. Thanks a million !!