Not that familiar with bathtubs so I need some help. I want to repair a chip in the bathtub myself but I am not sure what type of bathtub I have in order to purchase the correct repair kit. How can I tell what type of tub I have? The material behind the chip is slightly rusting anf leaving a stain, does this indicate a cast iron tub with an acrylic overlay or is it fiberglass? Thanks in advance.

I'm preparing for the reconstruction phase of my completely gutted bathroom. I believe it would be wise to put up a vapor barrier behind the greenboard (and cement board in the to-be-tiled shower). I've got this roll of 30 # building paper I bought for the new window flashing. My plumber says this will work just fine, layered low to high, overlapped 2-3". Questions: 1. Is this material a good choice, or would another (e.g. plastic) be better? 2. Do I try to keep the paper as continuous (uncut) as possible around the room, or cut it between walls? The latter seems easier to fit and hang, but I don't know how important it is to keep this layer as seamless as possible. 3. If and where I do cut it, do I need to seal the vertical seams, or is overlapping the paper enough? 4. Does this layer overlap the nailing flange on the shower receptor, as the cement board will, or attach to the studs right down to the floor (I believe the latter)? 5. Any seal needed where it meets the floor? 6. Is there a recommended stapling technique (like covering the line of staples with the next layer)? Any help with the specific details is much appreciated. I just installed the window, and the need for meticulous exterior sealing is on my mind...it may be that this level of concern is unnecessary here. Thanks, Mike Ithaca, NY