I'm replacing the caulk on my bathtub/shower, since it's in sorry shape.
See the images below. My house is about 50 years old and I believe these shower walls are original. They appear to be some kind of resin. For the interface between the (porcelain-covered cast iron) bathtub and the shower wall, I'm planning on using 100% silicone caulk. However, I understand that 100% silicone caulk isn't the right thing to use on paint or porous walls. What kind of caulk should I use at the interface between my shower walls and the sheetrock wall?