Epoxy does need protection from UV but using “spar urethane” varnish is not the way. I used a marine varnish with extra UV inhibitors. If you need to sand the epoxy do it before it gets hard or you will be there all day.Click to see full answer. Besides, can you cover epoxy with polyurethane?If your surface has an oil based stain or oil based paint, you must apply 2-3 coats of oil based polyurethane before doing the seal coat. The polyurethane will cover that and allow the epoxy to stick. This does not take the place of the epoxy seal coat as that is still necessary.Also, how do you protect UV epoxy? Add final finish coatings to your structure to provide UV protection, extra moisture resistance and more durability. Paint or varnish applied over an epoxy barrier coat is intended to decorate the surface and protect the epoxy from sunlight. Likewise, people ask, can you apply epoxy over varnish? As a general rule, epoxy should not be applied over other coatings. An exception is water-based stain (assuming it has been left to dry thoroughly) but anything containing solvents might cause damage to the epoxy layer, or the epoxy might soften the varnish/stain.Can you spray clear coat over epoxy?If it had a clear top coat of epoxy or polyurethane, it can easily be roughed up with sandpaper and have a new coat of clear applied. Once the new clear coat is applied, your garage floor coating will look brand new again.