Patrick’s Wisconsin Basement Hot Tub & Cold Plunge – Waterproofing, Tiling & a Surprise Water Feature!

We’re back with another update from Patrick in Wisconsin, and this one is a big one. If you’ve been following Patrick’s basement hot tub and cold plunge build, you’ll know he’s been at this for a while now – and things are really starting to look the part. In this latest update we’re looking at waterproofing, tiling, faux rock walls, and a rather exciting water feature that Patrick and his wife have been working on. Let’s get into it!

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A Quick Recap

Patrick has been building a hot tub and cold plunge combo in his basement. It’s a poured concrete build and he’s been kind enough to send through regular video updates along the way – which, I have to say, are absolutely fantastic. If you haven’t seen the earlier updates, I’d recommend going back and watching those first to get the full picture of just how far this build has come.

Waterproofing – Red Guard Goes In

This is one of those stages in the build that doesn’t look the most exciting on camera, but trust me, it is absolutely critical. Get this wrong and you’ll be in all sorts of trouble down the line.

Patrick has been applying Red Guard waterproofing membrane to the tanks, and he’s doing it properly – which is exactly what I’d expect from him. Here’s the process he’s following:

Primer coat first. You have to start with a diluted primer coat to get the Red Guard to absorb into the block and achieve a proper seal. It’s a step that a lot of people skip, and they really shouldn’t.

Multiple full coats to follow. Once the primer is dry, Patrick will be putting on a couple more full coats of Red Guard. You really do need to build up those layers to get a watertight finish.

He’s done this across both the hot tub tank and is working his way through the cold plunge too. Patience is key here – you need to let each coat cure properly before moving on.

The Cold Tank Gets a Water Feature Wall

Now here’s where it gets really interesting. In the cold tank, Patrick has been building what will become a fountain wall – or waterfall wall as he calls it. The idea is that water will trickle down the centre of the faux rock wall and into the hot tub. It’s a lovely touch and will give the whole setup a real spa-like feel.

The forms have now come off the top of the wall, and you can start to see exactly how it’s going to look. The faux rock has gone on the front wall, and the same rock finish will be used from the ledge height up on the back wall too, where the waterfall feature will sit. Patrick has also noted there’ll be a small bulkhead up top to contain the heat vents and other mechanical bits – all very neatly thought through.

A dedicated pump will handle the water feature separately, which is absolutely the right call. You never run a waterfall or water feature off the same pump as your jets – they need their own circuit. If you’re planning something similar, bear that in mind from the design stage.

Tiling Progress – Patrick’s Wife is a Star!

Right, let’s talk tiles. And let’s also give a massive shout out to Patrick’s wife, because she has pretty much mortared in all of the tile you see in this update – and she also picked the pattern. Excellent taste and excellent work. Patrick himself was very quick to acknowledge this, and rightly so!

Here’s where they’re at with the tiling:

Cold tank – tile is in and over halfway complete. Not finished yet, but well on the way.

Hot tub – just under halfway done. There have been a few challenges getting around all of the jet holes, which Patrick freely admits caused some frustration and a few broken tiles along the way. But they got there in the end – all tiles are in around the jets.

Footwells – still to be completed in both tanks. This is always the tricky bit. It’s a confined space and you have to be really careful not to knock tiles that have already been set while you’re trying to get into the footwell. Patrick’s approach of letting the walls cure out first before tackling the footwells is exactly the right way to go about it.

Tile caps – all cut and ready to go. They just need to be laid and mortared down once a special cutting project is completed. Patrick is adding little turtle shapes cut into the centre tiles, which is a really nice personal touch. Each centre tile will have its own little turtle inset – a great way to add some character to the build.

What’s Next?

Once the tiling is complete, the grout goes in – and then the whole thing needs to cure for a couple of weeks before Patrick can even think about filling it with water. In the meantime, he’ll be cracking on with the pump room and other finishing touches around the space.

Patrick and his wife are gunning for a New Year completion, which he admits is probably a bit optimistic – but they’re pushing hard and the end is genuinely in sight now.

Key Takeaways for Your Own Build

If you’re at a similar stage in your own build, here are a few things worth taking from Patrick’s update:

Don’t skip the primer coat on your Red Guard. It needs to absorb into the block to form a proper seal. A full coat applied straight to bare block without priming is not the same thing.

Build up your Red Guard in layers. One thick coat is not better than two or three properly cured coats. Do it right.

Plan your water feature from the start. If you want a waterfall or fountain effect, this needs to be designed in from the beginning – dedicated pump, dedicated plumbing, the works.

Tile the footwells last. Always. Let everything else cure and set, then tackle the confined spaces.

Broken tiles happen. Don’t panic when they do. Patrick had to recut several tiles getting around the jet holes. It’s part of the process.

Can I Help You?

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Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Fast forward to 2025, I've helped over 1400+ DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi