Placing Caldera on Gravel and Stone Dust

[ggggg]

My Caldera dealer suggested that if I did not want to go the concrete slab route as a base for my soon to be new tub, I could use an 8 inch gravel base and then top that with 4 inches of compacted stone dust.

He likes this better than using pavers and such, because the pavers can move independently of each other and cause racking.

Drainage is also no problem.

Has anyone tried doing this? Sounds like getting ready for pavers but then just not using them.

[Chris_H]

I would not deliver a spa on an 8-inch gravel base with 4 inches of compacted stone dust.  The spa would go back in the warehouse.  A spa is too great of an investment to screw around with one of the most important parts of ownership, the base that is supporting the spa.

[Drewski]

Hi NeedaTub:

Having a little experience with construction of outdoor structures, including decks and patios for hot tubs, let's see if I can help.

Straight up, in my OPINION, it really dosn't matter what type of base you put a spa on provided it offers STABILITY and LOAD CAPACITY. For a non-structural base, COMPACTION of grade materials is crucial to success.  I don't know why the dealer recommended gravel in this instance, I think plain old dirt is a better choice.  The 4" of stone dust is a good surface material, BUT think about what might happen to it if exposed directly to rain water, ESPECIALLY when layered over gravel.

Before I answer your question more thoroughly, could you post a description of the area where the spa will be placed including elevation, drainage, soils, etc.?  Also, is avoiding concrete a cost issue or requirement problem (i.e., you don't want to get a permit or the homeowner association dosn't like slabs)?

Drewski

[Spatech_tuo]

I've seent that done many times and as long as you use pressure treated lumber to construct a frame for the gravel to sit in and have good drainage I'd say its fine.

[newtotubbing]

If paver's are installed properly, and I mean properly (there is a wrong way to install them), you shouldn't have any heaving or racking.  Driveways are installed with paver's all the time, take a close look at a proper installation, not heaving, no racking, no rutting with cars, SUV's and large trucks driving on them for years.

I would be concerned about installing in the fashion you described.  For one, you will be dragging that stone dust into your tub all of the time, and two, it's just plain ugly.

Here is a like to photo showing my paver installation and then the completed job.

[link]http://www.pbase.com/jlefcourt/backyard_project[/link]

Jonathan