Doors and Windows - Refinishing fiberglass exterior door

I have a fiberglass exterior door less than 1 year old. I finished it as directed with a clear polyurethane finish, 3 coats. Now it has tiny spots of mold underneath the finish! It looks terrible! :( Of course, we survived 2 direct hits from hurricanes here this summer. So maybe all that water had something to do with it. Anyway, I want to redo it with paint. My question is do I just sand it and paint it with regular exterior paint? I don't know what product to use, and don't want to mess it up again. It's really a beautiful door and was expensive. Thanks for your help!

Sad but interesting to hear about the mold spots in (under?) the finish. Is there a storm door in front of this door? And which direction does it face? North, south, east or west? Sadly, the same thing might occur underneath the paint, since paint will not stop, nor hide mold for long. I just wonder what is causing the mold in the first place? Did the edges, top, and bottom also get polyurethane? Did you use polyurethane sanding sealer first? (Or maybe the polyurethane you used did not call for it.) Was it latex polyurethane, or oil based?


At any rate, if you insist on painting your expensive door, it would be important to strip the polyurethane off first, prime the door, and sand the primer before painting it. If you skip the stripping, and just sand it, there is no telling how good your paint will adhere, but my guess is, it would not stick well. And, in my opinion, if you're going to strip it, why not wash the door with Borax afterwards, and try sealing/varnishing it again? They also make staining kits for fiberglass doors, which are sold in stores. The ones I've seen are made by Therma-Tru.