Stone base question

[Pcola77]

We ordered our first tub ~10 days ago and I've been struggling to get contractors to do the electrical and concrete slab.  I think we finally got someone lined up for the electric, but in case I had to figure out a way to do the slab myself, this weekend I started digging a 10.5'x10.5' hole, 10-12 inches deep (to accommodate the frame for a 10x10 pad, 4 inches of stone and 6 inches of slab).

A few people, including the guy we bought it from, said to just do a base of stone.  I have a couple questions if anyone here has any good info that could help.

Details:
-The hot tub is a Wellis Monte Rosa, 91" by 91", ~400 gallons.
-I called the North America sales rep listed on Wellis' site in case my local guy didn't know what he was talking about.  He said the same, as long as its a level base, stone is fine. 
-I finished digging the hole, along with an 18" deep trench for the electric
-The tub comes 6/11, so just over two weeks.  A couple of the concrete guys say to wait 30 days before putting a hot tub on a concrete slab, so now I'm wondering if stone is the way to go.

Questions:
-Do you guys agree that a stone base is okay?
-Did I dig *too* much (since most things I've seen recommend a 4-6 inch base), or is there no such thing as too much stone?
-I know crushed stone is what's supposed to go under poured concrete, but isn't some of that sharp edged? Should there be a different type of stone for the top couple inches?
-I'm sure the electrician will probably know this, but I was curious of other thoughts.  Once we run the conduit, should I fill the trench with dirt, or with stone?  Wondering if the stone could do damage to the conduit.
-Anything else I should know?

Thanks so much for any help you can provide.

[hargabyte]

Have you considered using an EZ pad? I dont have any experiences with them but I hear they work well.

[Pcola77]

I did, but the hole is already dug, so at this point I’d have to fill it with stone and level it out for the EZ pad anyway.  So no real reason to spend the $500 for the EZ pad it doesn’t seem like. But I’m open to the idea if people think that’s better than just stone. Just didn’t seem worth it.

[CanadianSpaTech]

Youtube lots of how 2 vids for this. I lay down a few inches of 3/4 crush then make a 4x4 wood picture frame design with a couple of extra cross pieces level it and fill the open areas with limestone. I keep about 2' of the 4x4 above grade to keep water away from the spa base. I make sure to measure the spa bottom and build it to the spa base frame. The spas bottom frame is usually a bit shorter than the width of the overall size of the spa. So that the side panel kinda overhangs the base and when water goes down the side of the panel it goes to the ground and not onto the wood frame if that makes sense.

[Pcola77]

Oh I like that idea. Hadn't seen it before.  Any advice on the type of 4x4?  just regular pressure treated? Something special?  Thanks!

Youtube lots of how 2 vids for this. I lay down a few inches of 3/4 crush then make a 4x4 wood picture frame design with a couple of extra cross pieces level it and fill the open areas with limestone. I keep about 2' of the 4x4 above grade to keep water away from the spa base. I make sure to measure the spa bottom and build it to the spa base frame. The spas bottom frame is usually a bit shorter than the width of the overall size of the spa. So that the side panel kinda overhangs the base and when water goes down the side of the panel it goes to the ground and not onto the wood frame if that makes sense.

[swilly1000]

Since you're speccing this out so carefully, have you got the electrical coming up through the pad underneath the tub where it connects to the control panel? 

Do it right and it is stealth and all-pro.

[CanadianSpaTech]

Oh I like that idea. Hadn't seen it before.  Any advice on the type of 4x4?  just regular pressure treated? Something special?  Thanks!

Youtube lots of how 2 vids for this. I lay down a few inches of 3/4 crush then make a 4x4 wood picture frame design with a couple of extra cross pieces level it and fill the open areas with limestone. I keep about 2' of the 4x4 above grade to keep water away from the spa base. I make sure to measure the spa bottom and build it to the spa base frame. The spas bottom frame is usually a bit shorter than the width of the overall size of the spa. So that the side panel kinda overhangs the base and when water goes down the side of the panel it goes to the ground and not onto the wood frame if that makes sense.

YES just regular pressure treated

[Tman122]

Oh I like that idea. Hadn't seen it before.  Any advice on the type of 4x4?  just regular pressure treated? Something special?  Thanks!

Youtube lots of how 2 vids for this. I lay down a few inches of 3/4 crush then make a 4x4 wood picture frame design with a couple of extra cross pieces level it and fill the open areas with limestone. I keep about 2' of the 4x4 above grade to keep water away from the spa base. I make sure to measure the spa bottom and build it to the spa base frame. The spas bottom frame is usually a bit shorter than the width of the overall size of the spa. So that the side panel kinda overhangs the base and when water goes down the side of the panel it goes to the ground and not onto the wood frame if that makes sense.

I actually like to use extra 4x4 cross braces spaced about 8" center to center and cover with treated plywood. A big wood platform sitting on top of a compacted crushed stone base.

[Pcola77]

I'm definitely trying! The issue is that these tubs are not common in the US yet, so I have been unsuccessful in finding any info, and my dealer has not been very helpful in getting details (I know, big red flag, but with COVID and wanting to have one as soon as possible, we went with the size/color combo we wanted, as opposed to selecting based on the dealer like so many of you recommend).  There is one on the floor in one of their showrooms about an hour away, so I might actually go up there to look at it, do measurements, etc.  I did dig a trench to where the dealer said it should come up (midpoint left and right, and 4" in from the edge), but I want some confirmation.  The dealer said there is no pre-drilled hole, so even if it's not perfect the hole can be put where the conduit is.  We'll see...

Since you're speccing this out so carefully, have you got the electrical coming up through the pad underneath the tub where it connects to the control panel? 

Do it right and it is stealth and all-pro.

[Pcola77]

Thanks TMan.  You talking about an X-shaped cross brace, a plus-shaped one, or parallel (like deck joists)?

Oh I like that idea. Hadn't seen it before.  Any advice on the type of 4x4?  just regular pressure treated? Something special?  Thanks!

Youtube lots of how 2 vids for this. I lay down a few inches of 3/4 crush then make a 4x4 wood picture frame design with a couple of extra cross pieces level it and fill the open areas with limestone. I keep about 2' of the 4x4 above grade to keep water away from the spa base. I make sure to measure the spa bottom and build it to the spa base frame. The spas bottom frame is usually a bit shorter than the width of the overall size of the spa. So that the side panel kinda overhangs the base and when water goes down the side of the panel it goes to the ground and not onto the wood frame if that makes sense.

I actually like to use extra 4x4 cross braces spaced about 8" center to center and cover with treated plywood. A big wood platform sitting on top of a compacted crushed stone base.

[CanadianSpaTech]

Not sure about the plywood top...good spot for water to pool under the spa...or am I missing something? I just back fill the openings with limestone so it can drain away any water.

[swilly1000]

I'm definitely trying! The issue is that these tubs are not common in the US yet, so I have been unsuccessful in finding any info, and my dealer has not been very helpful in getting details (I know, big red flag, but with COVID and wanting to have one as soon as possible, we went with the size/color combo we wanted, as opposed to selecting based on the dealer like so many of you recommend).  There is one on the floor in one of their showrooms about an hour away, so I might actually go up there to look at it, do measurements, etc.  I did dig a trench to where the dealer said it should come up (midpoint left and right, and 4" in from the edge), but I want some confirmation.  The dealer said there is no pre-drilled hole, so even if it's not perfect the hole can be put where the conduit is.  We'll see...

Since you're speccing this out so carefully, have you got the electrical coming up through the pad underneath the tub where it connects to the control panel? 

Do it right and it is stealth and all-pro.

I would not rely on the dealer telling you where to drill. It's a precise spot and if you  guess wrong you could be seriously screwed. My dealer got me a drawing from Master to pinpoint the entry point underneath the spa...and if not for my double\triple checking the electrician would still have missed the mark where the conduit came up from the concrete pad.

This question has undoubtedly come up before for your spa.  Consider contacting the manufacturer directly to get a schematic. You do NOT want to be discovering on delivery day that the conduit enters the spa directly underneath a pump or control pack or some other ridiculously impossible entry point!

[Tman122]

Thanks TMan.  You talking about an X-shaped cross brace, a plus-shaped one, or parallel (like deck joists)?

Oh I like that idea. Hadn't seen it before.  Any advice on the type of 4x4?  just regular pressure treated? Something special?  Thanks!

Youtube lots of how 2 vids for this. I lay down a few inches of 3/4 crush then make a 4x4 wood picture frame design with a couple of extra cross pieces level it and fill the open areas with limestone. I keep about 2' of the 4x4 above grade to keep water away from the spa base. I make sure to measure the spa bottom and build it to the spa base frame. The spas bottom frame is usually a bit shorter than the width of the overall size of the spa. So that the side panel kinda overhangs the base and when water goes down the side of the panel it goes to the ground and not onto the wood frame if that makes sense.

I actually like to use extra 4x4 cross braces spaced about 8" center to center and cover with treated plywood. A big wood platform sitting on top of a compacted crushed stone base.

No a picture frame as mentioned made from 4x4's with cross braces spaced 8" on center. Like you built a wall out of 4x4's the size of the tub and laid it on the ground.

[Pcola77]

Thanks, that helps.  Didn't know what you meant by cross braces. 

Appreciate everyone's help/thoughts on this.  I'll let you know how it goes!

Thanks TMan.  You talking about an X-shaped cross brace, a plus-shaped one, or parallel (like deck joists)?

Oh I like that idea. Hadn't seen it before.  Any advice on the type of 4x4?  just regular pressure treated? Something special?  Thanks!

Youtube lots of how 2 vids for this. I lay down a few inches of 3/4 crush then make a 4x4 wood picture frame design with a couple of extra cross pieces level it and fill the open areas with limestone. I keep about 2' of the 4x4 above grade to keep water away from the spa base. I make sure to measure the spa bottom and build it to the spa base frame. The spas bottom frame is usually a bit shorter than the width of the overall size of the spa. So that the side panel kinda overhangs the base and when water goes down the side of the panel it goes to the ground and not onto the wood frame if that makes sense.

I actually like to use extra 4x4 cross braces spaced about 8" center to center and cover with treated plywood. A big wood platform sitting on top of a compacted crushed stone base.

No a picture frame as mentioned made from 4x4's with cross braces spaced 8" on center. Like you built a wall out of 4x4's the size of the tub and laid it on the ground.

[Pcola77]

Here’s my work, and what I ended up with. Tub comes Thursday!