Out With the Cedar, In With an ICF Inground Hot Tub

Right, I’ve got a brand new project to introduce to the channel today – and this one’s got a really interesting backstory that I think a lot of you are going to relate to.

Meet Jeff from New York, USA. Jeff’s been running an old cedar hot tub for somewhere around 10 to 15 years now, and as much as it’s served him well, the wood has finally had enough. It’s leaking, it’s tired, and it’s time to go.

But here’s the thing – the reason Jeff went with a cedar kit tub in the first place is exactly the same reason I ended up going down the DIY route myself. No access. He simply couldn’t get a plastic shell hot tub into the space. So back in the day, a handyman assembled it on site from a kit, and that’s what’s been sitting there ever since. Sound familiar to anyone?

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So What Are We Replacing It With?

This is where it gets interesting. We’re going in with an ICF inground hot tub – and if you’ve not come across ICF before, it stands for Insulated Concrete Formwork. I always describe ICF blocks as Lego for adults. They stack together easily, you can carry them in by hand, and once they’re in place you fill them with concrete mixed on site. No crane, no ready mix lorry trying to squeeze down a narrow access – perfect for exactly the kind of awkward space Jeff is dealing with.

The access issue rules out poured concrete forms entirely, because you’d never get enough concrete in at once to do a full wall pour. ICF solves that problem neatly.

What’s the Setup Going to Look Like?

Jeff’s already sent over an early sketch and layout, and there’s quite a lot going on. We’ve got existing walls that need to be extended, new ICF walls for the tub itself, and an underground control room – which is actually where all the kit for the old cedar tub already lives. We’re going to repurpose that same space for the new equipment. Nice and tidy.

A few other key decisions have already been made on the spec:

Electric heating. Gas is out because of ventilation requirements, and air source heat pumps aren’t ideal for New York winters. So we’re going electric – straightforward and reliable for this setup.

No jets. Jeff’s not after the full spa experience with all the bubbles and massage jets. He wants a proper soaking tub – hot, clean, simple. So the plumbing is going to be much more swimming pool style than traditional hot tub, but with the heat cranked up to hot tub temperatures. I actually really like this approach for a build like this.

Sunken into the deck. The renders I’ve put together show the tub sitting flush with the surrounding deck, with some new decking going in around it. When it’s done, it’s going to look like it was always meant to be there.

Why I’m Excited About This One

This project has a lot of the same challenges I faced with my own build, which is part of what makes it so interesting to follow. Tight access, site-mixed concrete, working within existing structures – it keeps things honest. There’s no cheating your way through this kind of build.

We’re following this one from start to finish, so make sure you’re subscribed to the channel so you don’t miss any of the updates as the project progresses.

And if Jeff’s project has sparked an idea for your own space, get in touch – I’m always happy to talk through a project. You can reach me through buildahottub.com, and if you need parts or spares for your hot tub or pool, head over to parts4tubs.com for the USA or parts4tubs.co.uk for the UK.

More updates from Jeff’s build coming soon – I can’t wait to show you how this one takes shape.

Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

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