Must I pour a cement slab?

[solo]

You know, as I was marking off in my back yard where I want the tub to go, I realized that it probably needs to sit on a cement slab.  

Correct?

[Chad]

There are many different types of foundations suitable for spas but the one that is highly recommended is a reinforced concrete slab that has a minimum thickness of 4''.

[solo]

There are many different types of foundations suitable for spas but the one that is highly recommended is a reinforced concrete slab that has a minimum thickness of 4''.

OK...I am putting the tub in my back yard.  It will not fit on myh deck.  I don't have room inside.  So it is definitely going in my back yard, just off the deck.  

What are my options for what to put it on?  

[Chad]

Spa pads, pavers, concrete, decking, or just the Earth if you buy an Arctic(they have whats called Forever Floor that elimanates the need for a foundation and doesn't void their warranty). Just be careful as some manufacturers have set requirements in which you have to abide by in order to keep the spa under warranty.

[anne]

Mine is on a gravel bed, with the idea that it is more movable if needed, and it was a DYI (I have never poured cement).

[solo]

A gravel bed?    It sounds like a good idea because like you said, you may wish to move it down the road.  

Is that recomended?

[Chad]

Anne has an Arctic, so all she needed was a level surface to place the spa on. I already told you what's recommended for most(all) spas.

[anne]

A gravel bed?    It sounds like a good idea because like you said, you may wish to move it down the road.  

Is that recomended?

You'd have to find out with each brand what they allow. Yes, I have an Arctic, so theoretically I could put it on level dirt......but who would do that? I think that almost all dealers will recommend cement, as it is pretty foolproof, but packed gravel or pavers is still ok with some brands to maintain the warranty.

[TwinTowers]

I was going to ask the exact same question as the origanal poster. I am literally 5 minutes removed from getting a quote of $1500 for a conrete slab. . He wants to use 2x6's and re-bar. Its a 9'x11' slab. I was thinking somewhere around $600 would be about right using 2x4s and no re-bar.

What do you guys think about the idea of no re-bar and using 2x4s? Im up for considering crushed granite or some other alternative. I need to act soon. My spa is ready for delivery once I get my act together.

[Chad]

TT,

$15 per sq ft is 2 to 3 x higher than the going rate here in the STL. Have you collected multiple quotes? I think you'll be able to find someone out there to do it for cheaper.

What size spa did you buy? If it's a smaller tub, you might be ok w/o rebar or some other type or reinforcement. The reinforcement materials really shouldn't elevate the cost too much.

[Vanguard]

I'd say using a 2x6 is overkill.  You don't need 6" of concrete depth.

Go with 2x4 and, yes, I'd use rebar - just to be safe.  It can't hurt and shouldn't add that much.  You don't need 3/8" rebar, just the mesh stuff should be fine.

[WannaSoakNow]

My quote for a 4" reinforced 10' X 11' pad was $1,989.00. Way out of line for me!!!!! ( and I'm a Landsacpe Designer, go figure)
I decided to do it myself, with some friendly help. (Pullin' in those favors due)    
I have done slabs before, I just wanted to see what the cost might be to have someone do it for me.

What was decided is a 7' X 7' X 4" concrete slab using wire mesh w/fiber concrete. The base under the concrete will be of packed crushed limestone gravel at the depth of 4". The perimiter will have a drainage trench on all four sides. The rest will be a decking surround giving the spa a built-in look, allowing for a deck trap door for ease of acess to the inards of the spa. Bringing the whole area for the 6'6" X 6'6" spa to a total of the 10' X 11' area I originally wanted to have in all concrete.

2 X 4 is the usual way to go. I agree that 2 X 6 is over kill....My Hot Springs dealer told me that if I used a "Forever Floor" he would NOT be responsible for future problems, and may void the warranty.

I also should mention that "IF" you use gravel you may have a future problem with ants. Especially, if you live in an area that is warmer and has a problem with sugar/grease/carpenter ants...they love the gravel stuff and LOVE the foam in a spa for nesting.

If you do decided to go with a gravel base please dig out at a depth of NO LESS than 8". Place a double layer of landscape fabric at the bottom of the intended base. Then a layer of 2" min. of sand, then fill with your gravel. Pack the gravel firm (rent a tool that will hard pack it down. For the life of me, right now, I can't remember what it's called.) After you have done all that do a top derssing to the intended pad i.e. pea gravel, decorative stone, crushed granite etc...

I hope this helps....sorry it's long but, I do use this for my clients when they want an area for a heavy weight use.

Good luck in what ever you do.  

[D.P. Roberts]

TT,

$15 per sq ft is 2 to 3 x higher than the going rate here in the STL. Have you collected multiple quotes? I think you'll be able to find someone out there to do it for cheaper.

What size spa did you buy? If it's a smaller tub, you might be ok w/o rebar or some other type or reinforcement. The reinforcement materials really shouldn't elevate the cost too much.

I'm in Ohio, we're about to have a concrete patio poured for about $8.50 / sq. foot. It's three separate areas, 2x4 with rebar. So, I feel better about the price now (after three quotes). I have somewhat the opposite problem - rather than wanting to move a spa someday, I figure I'll probably want to upgrade my spa in a few years, so I don't want to have to redo the patio again to support a bigger & better spa.

[BearBath]

FWIW,
I went through the same decision process. Slab was expensive and pretty permanent. I chose to have a vibrated gravel base and I'm really happy! Any water from rain or from draining it, or just the drips off the emerging nudies (!) just soaks into the ground summer or winter. No problems in three years with critters making their way into the interior. My research really showed that it is personal preference. There is not a correct answer!
Cheers,
BearBath

[Chad]

 Pack the gravel firm (rent a tool that will hard pack it down. For the life of me, right now, I can't remember what it's called.)  

Hand tamp or vibrating plate tamp.