I picked up a package of Jones Stephens closet flange extenders today for a bath i remodeled. I'm sure you guys know what i'm talking about. It came with 1/2" and 1/4" spacers with gaskets attached. I usually replace the flange for a tile floor but I had no access for this one. It's self explanatory how to put them on but I was thinking should a bead of silicone be applied to the closet flange before installing the extenders?? The gasket on the extender seems a bit thin to compress enough to make a long lasting seal but using silicone doesn't exactly make me feel better either. The closet flange is pvc with a metal ring that the johnny bolts slide into and I have seen first hand what silicone can do to metal over time. What's the norm for installing these?? thanks farrington