Originally Posted by Bob Miller
It's not the surface of laminate floor that's the problem. It's what happens if any water gets in the joints or at the ends, or gets under the flooring that is the issue. Again, for a few extra $$ for a small amount, the stuff marked "waterproof" is a good investment.
Right, the purpose of sealing the surface is to prevent moisture from penetrating it at the seams and to facilitate clean-up as well as to keep the shine.
This helps keep the subfloor dry as well.