Gravel Base

[vooswing]

The slab my hot tub is on is pitched away from the house for drainage which causes about a 1" difference in height across the span of the tub. Today I spoke with my dealer about leveling the tub and he suggested I make shims out of 2x4's to make a frame and then fill with peat gravel to form a solid base to support the tub along the entire base. Sounded easy enough so that is how I spend my afternoon today.

My concern is I ripped the lumber to make shims that narrowed from 1" to nothing and when I put in the gravel I couldn't fit it under the last foot or so because the shims were only about 1/8" deep by that point. Will the tub base "give" enough to cover the 1/8" inch or am I risking cracking my tub because it's not fully supported? I also lowered and lifted my tub several times to adjust for any low or high spots and the gravel looked great to the eye but I'm wondering if slight variations in the gravel base could also risk cracking the tub.

Thanks for any insights.

[Hotsprung]

Although I'm no spa expert, and cannot comment on the merits of the solution, I have been caught out this way before on other projects. I would buy new wood and make one end 4" amd the other end 3". That way you allow for you pitch and can still get the gravel in. It will also allow you some depth to compact the gravel if needed, improving the overall support.

My hotspring install instructions included details on the load points on the underside of the tub. If you can source it, your manufacturers documentation might do the same.