Gardener / engineery guys is this a good idea?

J

jbj

Poor old Geordie's array...
OK I have a hot tub arriving next week and have been trying to work out what I'm going to place it on.

Most of my garden is gravel but that's not going to be ideal and the area I want to put the tub on mildly floods.

I have a couple of options:

1. is build a ground level deck - I've been having a think though and the thing weighs 2 tonnes with water before anyone is in it - I'm pretty sure a deck would very quickly start sinking - am I right?

2. Is lay some sort of patio where it would be going. (possibly using a pathmate mould type thing) Again, I'm not sure if this would sink if I didn't properly grade the ground it was going on and I don't think I've got the patience to dig a huge hole in my garden to fill it properly plus my garden slopes towards the house so that would need to be dealt with.

3. This is my latest idea: Buy a bunch of railway sleepers and lay them out every 30cm perpendicular to the fence the tub will sit at and frame the ends essentially creating a big sandbox built of sleepers, fill the gaps between them with ballast or sand to create a completely level riser (to equally disperse the weight. And then either deck over the top or do the pathmate patio thing.

My thinking is that a design like number 3 would disperse the weight much better than the other two options, not be an issue with drainage and be a fairly straightforward build.

But then I might be completely missing something so wondered what you guys thought.
 
The nice thing about railway sleepers would that they might come treated already. If so, they would resist moisture and termites.
 
Have you checked your local library home improvement section (or Home Depot/Lowes) for books about decks and hot tubs? There must be books about this exact problem.
 
QUOTE="jp_nyc, post: 1117816, member: 2406"]Have you checked your local library home improvement section (or Home Depot/Lowes) for books about decks and hot tubs? There must be books about this exact problem.[/QUOTE]

Ive done alot of googling and im pretty sure its a non starter unless I want it to turn into a major and expensive job.

this idea ive had would be quick, involve next to no maintenance and its a mobile tub so if it did start sinkin I could just empty it move it out of the way and add more ballast.
 
If it were me, I'd put footers in and then timber across those (Like you would with a deck).

As you said though, it is "portable", so if it starts to dip or sink in a few years, you can always move it around (though I know this would be a PITA).
 
By footers do you mean sleepers?

ive come up with a pretty nice design. I dont want to half arse this then regret it and be stuck with something ive got to tear down next year.

will do a classy rendering in paint or excel :embarrassed: and share in a bit.
 
I have never heard the term "sleeper" before......
Something along these lines, and just build your frame right on top of it. Just keep it up off the ground, pour these every 4 feet and I can't imagine you would have any issues at all. Just dig it out down below the frost line.
bib-concrete.jpg
 
https://scontent-lhr.xx.fbcdn.net/h...=6ec7ac01fc3bfeae14781ce06de2997e&oe=55B6702A

Here's my current idea.

The whole thing would be set down then the inide of the frame filled about half way with aggregate (the things are about 10 cm deep) the last 5 cm would be done with 20ml gravel, pebbles or somethine like that. I've got loads of pallets out the back (aborted earlier idea for the deck) so would tear them apart and make a walk way down the middle of the deck but that would be sitting right on top of the gravel and aggregate too.

I'd have the sleeper joists joined with galvanised reinforced right angled brackets, possibly two for each join.

That's going to hold yeah?
 
How much bigger is this 'deck' than the hot tub?

The bigger, the better as that will spread the load out more across more ground.
If it's not much bigger than the tub, then you're just stacking weight on top of weight over the same surface area.
 
I knew someone who had a suana on a trailer took it with when they moved. Check with local building inspector or builders association before investment, that's what contractors do.
 
Dig a french drain to deal with the flooding, lay down a foot of medium gravel, then do the second "sleeper" link you posted. Note: over here they are railroad ties.
6-foot-AA-Railroad-Tie-Bundles.jpg
 
dodgechargerfan said:
How much bigger is this 'deck' than the hot tub?

The bigger, the better as that will spread the load out more across more ground.
If it's not much bigger than the tub, then you're just stacking weight on top of weight over the same surface area.
Click to expand...

It's not going to be a whole lot bigger.

Tub is 2m diameter, deck will be 2.4 x 2.8

The thing is, if I put a deck down, all of the weight is being put on the joists which is why I think they'll eventually sink, with this design the weight is going to be displaced through the gravel out as well as downwards and the sleepers / railway ties / big fuck off bits of wood that construct the frame will take a load too (if they can handle loaded freight trains I'm sure they can handle this....
 
Got a guy I know who's an area manager for a major building firm coming up next week so I can explain what I'm planning to do and tell me whether it's feasible or not :thu:

On another upside - After 2 months of abject procrastination, my kitchen retiling project is coming to an end (will be done tomorrow) and is looking fab :)
 
I'm gonna work this in English units since that's what I'm used to:

Tub is 2m in diameter. That's about 6.5'. So 3.25' in radius, or about 33.2 square feet in area.

The thing weighs 2 (presmably metric) tons, plus let's figure on 5 full sized adults. Call it 5,400 lbs.

Dividing 5,400 lb by 33.2 square feet gives a ground pressure of 162 PSF. That's not going to be a problem. Even lousy soils will give a bearing pressure of 1,000 PSF or so.

You can certainly do a lot of things to dress up the installation, but something like 6" of gravel on grade should support it just fine. Just be sure to remove the sod and topsoil, and then get the gravel that still has the fine particles in it so that it will compact, and tamp it firm in several lifts as you place it.

Disclaimer: this is all for an on-the-ground installation. Things get a lot more complex if you're considering a deck or other structure to support it.
 
Last edited:
I was telling my plan to a mate who has a Phd in physics and he did a couple of calculations :grin: :facepalm: and thinks if it's set up the way I'm thinking there's be something like 250g of weight per cm2 on it so unless my garden suddenly turns into a bog, I reckon it will manage :thu:
 
You must log in or register to reply here.
Back
Top