Hot tub liner

[stevo wis]

Folks,

I am building a round cedar hot tub and want to put some kind of liner inside that will be attractive, allow insulation between it and the cedar, and be waterproof. It will greatly simplify the joinery and time if I can find something that will work. Does anyone have any idea for a liner and maybe a cover?



thanks,
Stevo

[Bruce King]

I would buy a round spa then build the exterior.
You need thick foam insulation and water properly isolated from the electrics.

[Richard Coers]

Must be someone making the right sized polymer water tank. Then you could cut off one end.

[Bill Dufour]

Buy a rubbermaid stock trough.
Bill D

[Doug Garson]

There are hot tub manufacturers that sell vinyl liners for their tubs, maybe you can buy the liner from them if you match the dimensions. https://snorkel.com/hot-tub-products/general-accessories.php

[Bobby Robbinett]

Simply building a cedar box and dropping a liner in won’t get you a functional hot tub. You need some ridged to hold the liner once filled up with water and something that will support humans while they sit inside of it

[Howard Pollack]

Google water tank liners. There are several companies that produce them. You can ask them about the heat, but I doubt whether that would be any problem at all. Prices vary. -Howard

[stevo wis]

Thanks for the suggestions so far.
The dimensions I am considering are 5 or 6 feet in diameter and 4 feet high. I havent had any luck finding a stock tank or plastic bottle that large yet. I will talk to the snorkle people and another idea was to just use cedar, seal up the edges as the boatbuilders do, and then coat the inside with an epoxy.

Any more future suggestions are welcome.
thanks,

[Doug Garson]

Traditional cedar hot tubs don't use epoxy or even boat building sealants. They relied on the wood swelling when wet just like a wine barrel or a wooden bucket. Talk to a tub manufacturer before you decide. I had a traditional cedar hot tub back in the 80's. I bought it used and added a vinyl liner with a stainless steel ring around the outside to hold the liner in place. The tub also had galvanized rings to hold it together, if I recall the SS band replaced the top ring. We had a pair of benches inside to sit on. Can't recall if they were free standing or if I screwed them thru the liner to seal them. I suspect they were screwed with stainless screws and some silicone sealant, that's likely what I would do today but I'd ask a tub manufacturer for advice when I bought the liner if I were you.

[Bill Space]

Another option would be to line the tub with fiberglass. I built a Japanese bath which is an area about 10 by 9 feet, that has an integral tub, with raised seats at one end. I built the form, insulated of course, and then covered it with the fiberglass. The fiberglass is continuous from the tub, across the floor and up the walls a couple feet. Floors were sloped with cement then covered with plaster to keep down resin absorption by the cement.

The reason for this is that with a Japanese bath, you wash on the outside (floor drain there) and soak in the hot water afterwards. This is different than a hot tub, but water is water and a tub is a tub.

One problem with molding fiberglass in place is the surface does not cure completely, as it needs no exposure to air to cure completely, so it will watermark. It will also not be perfectly smooth. I believe watermarking can be dealt with by coating with a good epoxy paint. Might even be possible to coat with wax after initial hardening. Do not know. But the end result would still be less than perfectly smooth.

I got my fiberglass matt and resin from a small place that did fiberglass work. That place was referred to me by a resin supplier that was not interested in supplying small amounts of resin. Probably 20 gallons of resin. Worked for me.

Just suggesting this as a possible option. Might work for you, but it is not for everyone.

[Dave Sabo]

I'm with Bruce on this, why re-invent the wheel ?

Just build a cedar surround for something that already has the engineering and production solved.

[Bill Dufour]

Cast concrete. make you own.
Bill D

[Dave Sabo]

Cast concrete. make you own.
Bill D


That is going to be very difficult , basically impossible given the size and shape.

[Bill Dufour]

That is going to be very difficult , basically impossible given the size and shape.


No size and shape was given. I assume it sits flat on the ground not on a raised deck.
Bil lD.

https://www.jensenprecast.com/Agricultural/Water-Trough-p15460/

(https://www.jensenprecast.com/Agricultural/Water-Trough-p15460/)https://www.ntotank.com/1000gallon-duracast-blue-aquaponic-open-top-tank-x4486245?gclid=EAIaIQobChMIsY2K2rPf7AIVjIbACh2EvAq AEAQYASABEgL_ofD_BwE


https://www.tankandbarrel.com/open-top-water-tanks-crmi-800ott-custom-roto-molding-800-gallon-open-top-tank-p-1930.html?gclid=EAIaIQobChMI5qmjn7Pf7AIVE_3jBx2P1Q u4EAQYASABEgLCdfD_BwE

https://theconstructor.org/structural-engg/rcc-water-tank-design-requirements/6717/

(https://theconstructor.org/structural-engg/rcc-water-tank-design-requirements/6717/)https://wieserconcrete.com/product/septic-holding-tanks/


this one has free delivery if the op is in Australia.
https://dallcon.com.au/product/round-cattle-water-trough/

[Bill Dufour]

Four feet tall is very tall for what can be bought. Buy a piece of 6' pipe and make a bottom. Or buy two of the poly tanks and cut out the bottom of one and glue it onto the other. Easier in poly then in concrete. What is your location so we can give more local suggestions. Are you in Australia?
Bil lD

[Bill Dufour]

https://www.ebay.com/itm/Stainless-Steel-Tank-800-Gallon-Capacity-Used-in-Food-Service/183919946582?hash=item2ad27bab56%3Ag%3ARWMAAOSwd2J dVDN4&LH_ItemCondition=4

[Doug Garson]

One additional comment, you don't need much, if any, insulation, between the liner and the wood, 1 1/2" to 2" of cedar is pretty good insulation.
For a cover you could make something like this. https://www.pinterest.ca/pin/459507968215525489/

[Tom Bender]

If you are hoping to save money over the cost of buying new you will do better to buy a used tub from someone who got tired of using and maintaining it. The effort to clean it up and set it up will be far less than kludging something together. It will come with all the accessories you would need to buy anyway at full price, like a pump, wiring, plumbing, heater, lights etc.

[stevo wis]

hi folks,
I am getting there slowly and some good suggestions were given.

Let me answer some of the questions that were given.

1. We are limited in our size so whatever i build has to be less than 6 foot in diameter.
2. I already have the cedar and can make stainless steel bands easily.
3. We have looked for used and most of them are too big or junk so far.
4. I am a woodworker and want to build one. I have owned spas before and can wire an plumb it. It will take a while though.
5. The plan i have calls for 48" high, 60" diameter.
6. What i have read says that cedar leaches a lot into the water and makes a "tea" that I would like to avoid.
7. I can join the staves and make it tight enough but a liner would make things easier and less leak prone.
8. I live in Wisconsin.

Bill Defour's responses show several links that might provide a plastic liner that might work.
Anyway keep it coming.


thanks,
Stevo

[Dave Sabo]

No size and shape was given. I assume it sits flat on the ground not on a raised deck.
Bil lD.

https://www.jensenprecast.com/Agricultural/Water-Trough-p15460/

(https://www.jensenprecast.com/Agricultural/Water-Trough-p15460/)https://www.ntotank.com/1000gallon-duracast-blue-aquaponic-open-top-tank-x4486245?gclid=EAIaIQobChMIsY2K2rPf7AIVjIbACh2EvAq AEAQYASABEgL_ofD_BwE


https://www.tankandbarrel.com/open-top-water-tanks-crmi-800ott-custom-roto-molding-800-gallon-open-top-tank-p-1930.html?gclid=EAIaIQobChMI5qmjn7Pf7AIVE_3jBx2P1Q u4EAQYASABEgLCdfD_BwE

https://theconstructor.org/structural-engg/rcc-water-tank-design-requirements/6717/

(https://theconstructor.org/structural-engg/rcc-water-tank-design-requirements/6717/)https://wieserconcrete.com/product/septic-holding-tanks/


this one has free delivery if the op is in Australia.
https://dallcon.com.au/product/round-cattle-water-trough/


um, Bill , now you’re off the deep end. You said: “Cast concrete. make you own.“

Even changing your mind, half those links aren’t concrete and delivery isn’t gonna be “free” for any available in Merica .


But I’m glad stevo got a lead out of them.

[Doug Garson]

Just in case you haven't seen this one, Samurai Carpenter Youtube videos, he also has free plans, how to video but no liner.
https://www.youtube.com/watch?v=93vSe3vYqTA

https://www.youtube.com/watch?v=pZ6nzOUv48A

[John C Bush]

A friend built a cedar hot tub many years ago and it worked really well. Clear cedar was reasonable back then and I don't recall any issues with a "cedar tea" effect. An episode of "Dirty Jobs" featured building a roof top water storage tank for an apartment bldg in NYC and don't remember if they used cedar or redwood. Not sure if it was for domestic use or fire control system-but was an interesting build.