[Project] New Hot Tub & Base (With Updates)

[RedKnight]

TL;DR - I Built Something to help me.

Promise this is not going to be a short one.
So backstory I've done my back at work. The heat from a bath/hottub is the only thing keeping me mobile at the moment.
I used to have one in the same position over 12 months ago. My garden isnt level. It was on heavy clay soil protected by thin insulation foam matts and weed fabric cloth. Not ideal for a first hot tub.
A muddy mess come mid-winter.


PROJECT
Two problems (Money) I can't afford £1000's to have a concrete or gravel base dug this time around.
No friends or family to do the work either. I don't have any wood skills or tools.  The last time I did a french drain it nearly killed me with the digging and gravel.
So I need a hot tub for recovery, but my back can't do the work. Second problem (Time) I need this now, not in weeks or months later.

So I've been doing research about alternatives.  Insulation Board.  Now I hear you cry. What?
Well for a hot tub base, you can use Extruded Polystyrene (XPS) insulation board with a heavy compressive strength. High-density XPS is ideal because it resists water absorption and prevents the heavy hot tub from sinking, unlike standard EPS foam.
So I had to work out the weight of the hot tub full with water and with two heavy occupants. And lots of room for error. I went with a 2 inch thickness.  This not only provides better insulation. Its stronger. But also keeps the tub higher off the ground from dirt.

TUB
So yes. I bought an expensive new hot tub (after much searching) that was actually an easier choice. My old one was a St Lucia 2. I had all the attachments including a round inflatable seat. Two set of ready jetwashed round matts. All the chemicals of a Breaking Bad lab. And a brand new canopy sitting ready.
I avoided the ex-display models the local B&Q were shipping with likely more holes than swish cheese.  The new model is energy sense meant to be 40% more energy saving. So the difference in price would be saved in just a few months.
It fits me and my girlfriend and thats enough for me.

So as usual with Amazon it arrived the next day. But had to sit waiting until I could get all the parts to the base.



Yes it came with a slight dint in the bottom left corner. I was worried how far the shock penetrated the hot tub.

BASE
Now the size of the insulation boards I ordered arent the size you can fit in your car. Mine were two metres high and one metre wide. Less than a £100 total.
Until those arrived I had to dig the area over. remove the old weed fabric. Level it.  Expand the size given I made the decision not to cut the insulation board which means losing a bit more of the garden but means I can walk around it to take the canopy off.
And less messing delaying using it given my back was killing me.  I had some left over membrane from my soakaway project and a new roll of weed fabric. Enough to direct the water away from the base. and hopefully keep it all from becoming a mud patch again.

Not exactly level a slight slope to ensure any water runs into our garden and not the fence and next door.

So the two boards I ordered arrived. Decisions were which way to run them horizontally or vertically. I chose not the have the middlr which would be taped near the entry point aka highest traffic area.


DPM Damp Proof layer!
I had the boards on boxes whilst I painted with a liquid rubber by Siramico a liquid DPM layer. Very expensive paint. £70+. Picked grey to match the tub. It broke a few paintbrushes so I had to rush out to get a roller in the end. It's meant to be one coat. But I had enough to do two, giving a day for the first to dry. And a little bit for touchups down the line.
I did get a little unexpected rain on the first coat, had to cover them, but I hid the little damage to the underside for aestetic reasons only.


Now these board are water resistent'ish but not fully meant to be exposed to UV and the seasons. So I bought an exterior (walk-safe) paint. One which hopefully wont flake and keeps enough hydrophobic properies to keep the base dry.

Bigger problem than the rain was the wind. and try to get them lined up so I could tape. I had them vertical against the adjoining fence. And used a roll of aluminium tape from top to bottom. Then painted over it. No pictures of it in the air. because I was holding onto them for dear life.
No rain. But I knew a big gust of wind and these would part like Moses and the ocean.

So I laid them down gently. Slight movement so not perfectly positioned but they aint moving again.  The last of the aluminium tape fixed them together for the final tape. More painting





Now had to impatiently way for everything to settle and dry. No rain forecast thankfully.

FINISHED Base




No Wood/No Gravel/No Concrete. Just Insulation Board.

A few days later. Time to put the matts down. I had a cheaper set which I was planning to underneath the expensive set. They dont overlap in jigsaw pattern so this would again be more insulation, all the merrier.
I had more weed proof fabric left over so I wantto cut around the hot tub and the seating But also the side where the lid will go when its off the tub.
But I wasnt exactly sure where the tub would go. slightly back because of the filter/air machine and the foot bath to wash off dirt where you get in.  So I wouldnt cut till later. just peg everything down to stop the wind taking my foam pieces off like a kite.
I wouldnt recommend doing this on a windy day. I did try to tape them with various tapes but nothing would still.

Time to open the LayZ Spa

Less pictures of this bit.

Laid everything out on the matts. Blew up the base. Moved it to position where machine would be. Blew up my old hot tub seat. Yes it does need another good soapy jetwash. But I needed it out to work out where the hot tub posisiton should be.
Matts all out. Foot bath out. etc. Checked where the rain water would come off the canopy. Now my canopy doesnt exactly fit this model. but I have pegs/metal hooks to stake it into the garden. On heavy winds I take it down anyway.



And there she is.
https://qday.forum/postedimages/hottubfilled.mp4

Mega chlorine shocked the water. PH tested, + and - etc. So would be a few days before I could get in it for real.

Thoughts? My back is hurting but it has been a success. So far the insulation boards seem happy enough. I little touch up needed but that was to be expected.
We've had heavy winds/snow/hail/rain/frost/sun and so far so good.

Changes?
Maybe I would consider adding a wooden deck if it becomes a problem or need to high the sides.
I will be very careful with weed whacker/strimmer for sure.

UPDATED
Still working great. Almost daily usage at the minute.

Question answered?
Would I have risked this with a more expensive hottub. Probably not.  If I move in future I would build a more permanent structure. Time will tell with energy savings or not.
No complaints yet.  Just need to sort the rest of my the garden now once my back is better

[Undertaker00]

Thats Great mate

[Andy89]

I would love to have one. But I feared gravel or concrete hell

[Louise84]

Good to know I can use it outside

[Clever Wrench]

Only XPS. other stuff isnt as safe

[KeyboardWarrior47]

That is the nuanced version of it. I find the most honest reactions come out a while after the initial response settles.

Happy to keep discussing this.

[IronQuarry48]

Kind of what I thought yeah. Let me know what you think

[StringTheory83]

Fair point, I would not argue against it. It always comes down to who wants it more in the big moments.

Good debate though, fair play

[One-One-Five]

That is pretty much it. That is the thing isn't it.

Appreciate it.

Buying decent materials and cutting corners on tools is usually a false economy

[MondayMoan51]

That is the nuanced version of it. I find the most honest reactions come out a while after the initial response settles. Happy to keep discu

Not sure that is the whole picture. I find the financial angle of any big story is usually the most underreported part.

Worth watching closely

[Stu96]

I still can't believe how good this looks 

[RedKnight]

UPDATE: So we are several months in.

I love the hot tub. I love the base its solid/sturdy even with all the weight of the tub.
The paint on one side needs a little refresh from all the use
The sides probably aren't as hard wearing (ts foamboard after all). I may seen next year about setting a wooden skirt for it.

In the sun its fine.  Perhaps even completely wrap it to keep it good condition for future years.

My back is on the mend. So this was way easier than a solid permanent base.

[Frost Jay]

This turned out to be a seriously worthwhile project. The fact that the base is still solid after months with that much weight sitting on it is probably the best proof that the extra effort paid off.

A lot of people would have just thrown something together and hoped for the best, but a hot tub is not exactly the place to discover a weak foundation.

Nice to hear the back issue also got some relief from having a proper setup. A good soak after a long day is hard to beat.

[Jess_43]

Great update! The long-term test is always the interesting part with DIY projects. Photos on day one are easy, but seeing something survive months of weather and actual use tells the real story.

The paint needing a little attention is almost expected with outdoor projects. Nature seems to take personal offence whenever humans try to keep things looking nice.

Still, a small maintenance job on a base that is doing its job sounds like a pretty good trade.

[Isabella_61]

This is exactly why I enjoy seeing full project threads instead of just finished pictures. The planning, mistakes, fixes, and updates are usually the most useful part for anyone thinking about doing something similar.

Sounds like the base was the right decision too. A hot tub full of water and people is a lot of weight, so having something stable underneath removes a lot of worry.

Enjoy the tub! Just be careful, because once you get used to having one, normal baths are going to feel like a very disappointing puddle.