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Do yourself a favor and worry about other things besides the shell. Both shells will last a very long time and the shell material should not make/break your decision.
No, a HotSpring spa shell will not support the water without the foam. But that's like saying your house will not support the roof without the walls. It is all part of the way the tub is engineered and built. A Sundance would never support the water if you somehow removed the fiberglass backing...
Should I worry about the Hotspring acrylic stifness? [glb]No, it will last as long as any other spa shell, longer than most[/glb]From what I read on this forum, The foam is what is supporting the acrylic. What will happen if we have to dig the foam because of a leak? will the structure be as strong as before?[glb]Yes, we have never had a problem with this in the 21 years we have sold them. In the highly unlikely event that a leak developed, the spa would be repaired and refoamed as good as new[/glb]
The question wasn't alluding to the backing and why it's stronger, it was about removing the foam if it leaks. If you have two pound foam around the tub, it leaks and is replaced by spray in half-pound foam, is the tub weaker in that spot because it needs the two pound foam to support it? I don't know the answer for HS, but if the Sundance shell is indeed self-supporting because of the fiberglass backing, then for sure the answer is no it is not weaker. I believe that is to what the question alludes.
HotSpring sells more spas than any other spa company in the world. They would not be #1 if they made an inferior product. Chris H was right when he commented that there are other more important issues when searching for your spa. They are both great spas and I'm sure you will enjoy which ever one you decide on. Terminator
Why did Watkins Mfg. reduce the Hot Spring shell warranty from 10 years to 7 while maintaining a 10 year on caldera. Hot Spring is the more expensive product, should it not carry a longer structural warranty. Or is it that Watkins and every Hot Spring dealer out there knows that their shells have an astounding cracking problem in years 7 through ten, which Watkins has lost a boat load of money on.
What will happen if we have to dig the foam because of a leak? will the structure be as strong as before?