Are you talking about re-coating your tub or buying a new one?

I like my acrylic Kohler Underscore. It has a nice slanted back with lumbar support. Holds the heat well. It’s only been in for about 2 years, so I can’t speak to longevity.

Thanks Belaria. Buying a new one.

I'm not an expert on tub coatings, but I do know that if I were in the market for a new tub, I'd be looking for sure at Victoria + Albert or any brand of the tall, copper sit & soak freestanding tubs on the market. Small bathrooms with built-in tubs may not accommodate freestanding models, but that's definitely the direction design trends are going, to have freestanding tubs.

Thanks Belaria. Unfortunately I have to go with a basic soaking alcove tub that is 200lbs or less. Ideally, something that can last as long as it can be, very hard to crack/scratch yet very easy to fix and re-finish, and very easy to clean and very hard to discolor. 60" L is a must, 30" W is really preferred as it's a small bath, 15" H preferred but can certainly change for the right/great tub that meets those needs.

Unfortunately, I am still not 100% sure which material is better, acrylic VS fiberglass.

Thanks formulaross20. Apart from "structural longevity" which material of tub, fiberglass VS acrylic, would be more durable against stains and scratches ?

By the way formulaross20, a mortar bed seems great, but how would you strengthen the 4 sides of a plastic tub ?

The side walls of a tub don't need strengthening, they don't experience the point loads that the bottom of the tub does. The side walls do experience the outward push of water, but that water load is along the entire side length so the whole side surface flexes slightly and uniformly. That is OK. Even if you push sideways on the tub with your hand, you can't create significant side loads. What is bad is when the tub material experiences flexing in a small and limited area, such as a 300 pound man standing on one foot while showering. If not properly supported by a mortar bed underneath, that type of repetitive loading will ultimately fail the tub material. In your previous question regarding durability of fiberglass or acrylic, I consider them to be comparable.

Acrylic is a great material for tubs. Fiberglass isn’t. You’ll wear through the gel coat pretty rapidly with regular use.

Thanks The Cook's Kitchen. If the gel coat is gone, would the tub easily stain ? In other words, is the layer right beneath the gel coat porous or non porous ? Can the gel coat be re-applied like wax on cars or sealant on natural stones ?

From boat experience, the gelcoat is not very thick. If it cracks, water can penetrate the fiberglass over time. But the gelcoat can be repaired, there are kits for that. Color matching might be an issue... The gelcoat should be a couple millimeters thick, it is not a wax or sealant. More like 10 layers of paint.

I would think that fiberglass would be heavier, and would need the support so it would not crack.

For acrylic, the color goes all the way through. I would guess if you scratch it, you could put on a substance that would fill in the scratch. Its lighter and easier to handle. Some do require support, but I've seen some that do not. That is, the support is built in.

BTW: you can't use abrasive cleaners with either.

Thanks weedmeister. Are they alternatives to gelcoat once it wears out on tubs ? Epoxy ? Polyurethane ? Marine paint ? Anything that is water proof yet does not wear out fast like gelcoat.