Hello,
We bought a house with an inground fiberglass spa--10 person, make unknown, plumbing all seems to be Waterway. The spa shell is in good shape, but the second day we were in the in house, a leak floated the spa. We lifted the spa and repaired the leaks. Setting the spa back in the ground, the rim of the spa is supported on 2x6 treated decking. A local spa tech who examined it said we did not need to back fill all the dirt we removed. He said the rim was strong enough to hold the filled spa with no dirt supporting it underneath. I'd like more input on if I should back fill and how much support it needs underneath. Any help will be appreciated.
Jim

The rim, or "lip" is in no way, shape, or form adequate enough to support the spa shell. Virtually all the weight needs to be supported in the footwell, and a shell that size needs additional support under the seats.

Back-fill as much as possible.

Allowing the lip to support the weight will bend and crack it in no time.

Holy cow! Oh man... lol...

While you don't have to have 100% support around the outside of the tub, you do need 100% support underneath (footwell and seats if possible) - and NEVER support a tub by hanging it on the edge.

YiKeS!

Thanks for the responses. I will definitely backfill as much as possible. When we bought the house we had techs from two different pool & spa dealers come out and show us how to care for the pool & spa, after the spa floated I got bids from three different dealers for repairs, all I got was contridictory information and what I considered to be high prices ( $5000 to $6000 to reseat the shell not including parts or additional labor for repairs ). I have learned more common sense answers on this forum in two days then from experts I was paying, so again thanks for your help. P.S. I can now have the shell out of the ground in 30 min. or less, hope to never have to do it again but usful skill.

I had one of these years ago that wasn't seated in the ground, but in it's own brick shell -

Multi-mill property, owner removed sides, then enclosed with brick steps on 3 sides - the back faced a wall. Looked awesome for a number of years, until it developed a leak. To remove the tub had to demo a large section of the steps. Then I replumbed the 32 jets, suctions, skimmer everything. Dropped it back into the 'steps' with extra flex hose (and connectors) for everything so it could be pulled back out and flipped on it's face and worked on without having to demo the whole mess again.