Options for supporting a hot tub

[tubhunter]

What kind of base are people using to support their hot tubs?  I'm thinking of the following 3 options:

1)  Build a small deck out of pressure treated wood (8 X
2)  Build a frame out of pressure treated wood and fill with gravel
3)  Build a frame out of pressure treated wood and use brick pavers

Any thoughts or experiences with these methods is appreciated.  Thanks!

[anne]

I did #2, and I sort of wish I had done #3, as the gravel scatters a little at the edges. My wood box was made large enough to accommodate not only the spa but the steps, so there is some exposed gravel that I have partially covered with pavers.

[kervis]

From what I have read they are both good spas:  it really boils down to your personal choice (wet test .. wet test.....)  I can't talk to those spas but I can talk about putting a spa on pavers.

We bought a Hot Spring Grandee about six months ago (500 gallons, 1000 lbs empty, 6200 lbs filled) and were faced with the same dilemma.  Because of the size of the tub, the Grandee can't be shimmed for leveling:  the pad must be level.  Our tub sits on a small patio about three steps down from our deck.  We compared and considered pavers, flat concrete, and stamped concrete.  We put it on pavers and have been very happy.  The part of the patio that is under the hot tub has a deeper "foundation":  it was built to driveway specs vice patio specs.  The contractor who build the patio was recommended by the hot tub dealer.  I know several other people who put their tubs on pavers without problem.  The way I see it, if it will hold a car (2000 lbs nominal, maybe one square foot of bearing space for the four tires for a load of 2000 lbs per sf, it should handle a tub.  In the case of my installation, the footprint of the tub is 64 sg ft.  If we assume that the bearing surface is only 10% of the total area, given the weight of the tub that would be a load of 970 lbs per sf.  The bearing surface would have to be only 5% of the total area for the load to be equivalent to the working load for a car.  I admit this is a "back of the envelope" calculation, but I think it is reasonable.  I did it to double check what my contractors and dealers were advising me when we put our tub in this summer.

Another advantage of the pavers is that it is easier to combine the slope required for drainage on the patio and yet have the area under the tub level.  In fairness, you also need to consider the soil.  Our "soil" here is about 2 inches thick.  After that you need a pickaxe to break up the rock.  The builder had to blast to put in basements and foundations for the houses.  

The bottom line: based on my experience (admittedly limited) and my reearch (reasonably extensive) I would not worry about pavers providing they were installed to driveway standards.  

Good luck with your decision!

Bill

[kervis]

We have ours on pavers also--not to the degree that Bill has--just backyard patio pavers, with the regular base of gravel and sand, etc.  

So far, so good.

Some people complain of ants tunneling/removing the sand in between.  I haven't had that problem yet and will put down ant killer if I do!

[Tatooed_Lady]

we built a small deck off our main deck. it's roughly 8'x9' (tub's 7'7" x 8'4"), which leaves JUST enough room at the front of tub (by the step UP) for hoses to connect to the drain plugs without kinking. So far we haven't done much in the line of landscaping the surrounding area, but I guess that's going to wait for a privacy fence so I know more what we've got to work with.
We used PT lumber, some pea gravel....I think total cost was around $300 plus a weekend of our time to cut, screw, level, etc.

[Tyheethan]

I used PT 2x6 lumber and lowered the lumber into the ground 2 inches so that I had 4 inches above ground and filled with pea gravel.  My spa pad is exact size of the outside dimensions of the skirting on my spa.  I like this because my stairs are not on the gravel and there is no foot traffic on the gravel.  To date, we have had no problems with tracking  gravel because we are not walking on it.

I did drive a couple of re-enforcing stakes (2 on each side) so that the 2x6 sides to my spa pad would not bulge.  Might have been overkill but it sure made me feel better.

In the spring, we will  paver all around the spa pad-creating a little patio area with the spa (on the pea gravel spa pad) in the center.

Hope this helps (or at least makes sense )

[Bama]

I don't know much about hot tubs, but I do know about building.  I'm a woman who can handle her power tools!
It's all about your site.  Since the site is everything, my answers are rather general.

1) are you talking 1" X 6"  or  2" X 6" pressure treated pine?   Some people like the engineered wood...but I don't like it at all.
I recommend  2" X 6" pressure treated pine whatever route you take.

2) what kind of soil do you have and are you on a slope?  How do you plan to secure the gravel?  Gravel alone shifts and washes.  Are you talking about putting a frame down directly touching the ground, then filling with gravel?  I wouldn't want to do this  for long term unless the site conditions were perfect and you live in a dry climate with clay based soil.

3)  There are brick pavers and there are BRICK PAVERS...
    some are "sidewalk" grade and some are "driveway" grade.
the driveway grade is made from concrete with fiberous reinforcement in the mix.
Only the reinforced concrete is suitable for good long term support.
The sidewalk type pavers are not reinforced and will crack, it's only a matter of time.
When pressure is applied, they can crack immediately.

Above ground platform with minimal board cutting....
For an above ground platform measuring  8' x 8'  or even 10' x 10'... decide the size and use precut pressure treated pine boards in that length and 2" thick.  To build a square frame, use 4'' x 4" pressure treated corner posts.  Boards: Five 2" x 8" (or) 2"x 10" pressure treated pine decking, with the extra beam down the center.   Approximately three  2" x 4" PTP boards for cutting into short lengths to brace corners and  center beam.
Depending on your site whether or not I would dig a footing or simply use the pre-fab footing (ones that hold a 4" x 4" post).  Home Depot or Lowes has the pre-fab concrete footings for decks.  

Good luck,

Bama