My chimney crown is in need of repair. It is starting to crack in numerous spots. I was thinking of just slapping on another layer of cement over the old cracked one, then using some kind of water sealant like UGL Drylock. What do you guys think? Also have seen some crown sealers for this but they want over $100 for 2 gal of the stuff. Is there a cheaper way to do this? Thanks.