Not sure why you would want to use something water soluble as pva or emulsion? I forgot to check if my paving seal was polyurethane based, i have a feeling it maybe. I bought it to seal some slate flagging but the finish was too matt so it needs to be used. I only need to make the floor easier to keep the dust easier to manage and a bit more illumination is a bonus. I do have a ruck of sbr which is basically a waterproof pva but is a bit in the pricey side, I use it for flagging as it helps when laying marble and slate.
mike
mike