Full foam insulation- Fact of Myth?

[Skippyb]

Hello everyone.

 

I had a Beachcomber tech tell me that full foam tubs  like there's and several others, are not only the best for hot tub insulation, but because full foam from wall-to-wall, it stiffens up the tub making it more sturdier and making the plumbing less likely to move around and leak. So benefits of full foam:

 

- best insulation

- sturdier (less likely for the tub to crack)

- less prone to leaks.

 

Myth of Fact? 

[cranbiz]

Full foam does a lot of what he said. It fills most of the voids, it does secure the plumbing and therefore less prone to leaks.

Depending on the type of foam used, any leaks that might develop can be difficult to find. There are several types of foam used. Some gets hard when cured and stays hard, some cure and remains somewhat flexible. 

It's a generally accepted fact that a full foam tub holds heat better, which is why the better manufacturers use it and the lesser brands don't. It does cost more.

[ratchett]

As a product engineer, here's my take:  Yes spray foam insulation has several advantages over traditional stuffed insulation (mainly from an energy efficiency standpoint), which is why you'll see most of the big name brands use it on their main flagship tier spas.  However without the proper tools, spray foam can be a PITA to remove easily from a tub - if you're a weekend warrior who would rather DIY a fix instead of hiring a professional, spray foam tubs are not going to be your friend. 

Personally after waiting twenty years, I opted to spare no expense.  My tub has multiple densities of spray foam (depending on the location on the tub - high density close to the shell/plumbing, or low-density for filling the voids between the shell and cabinet walls) and it is extremely energy efficient (about $10 in the summer time and $13-$15 in electrical costs per month in the winter). But I also have zero intentions of performing any major maintenance/repairs myself on the tub - if there's ever a leak I'm calling my dealer's techs who spend 40 hours a week for the past decade+ servicing nothing but Hotspring spas around this half of my state.

2 hours ago, cranbiz said:

It's a generally accepted fact that a full foam tub holds heat better, which is why the better manufacturers use it and the lesser brands don't. It does cost more.

It's also heavier and costs more to ship 😉

[RDspaguy]

I have seen foam shrink and pull plumbing apart (mid 90s Sundance spas), and even sucked a jet right through the wall on a plastic shell spa (D1). And leaks are much more expensive to fix and nearly impossible to give an estimate beforehand. I tell customers it will cost $500 or more to find out how much it will cost to fix. 

More efficient... sure. Better... maybe. Worth it... not in Missouri.

[Cusser]

2 hours ago, RDspaguy said:

And leaks are much more expensive to fix and nearly impossible to give an estimate beforehand. I tell customers it will cost $500 or more to find out how much it will cost to fix.

 

My 32-year-old CalSpa has expanded foam insulation.  And now we all know why I use liquid leak sealer like once a year to stop a leak which appears to be leaking on the side just 1 foot from the house's south side (block).

I wouldn't have a clue how to move the away from the home and/or tip it up to try to find a leak without breaking the spa completely in that process !!!

[Skippyb]

Cusser 

What's the name of the product so that I have it on standby. I haven't noticed any leaks yet, but my tub is only an 2008. I would love to get anywhere close to 32 years out of a tub!

RDspaguy, what would cause foam to shrink? Are there steps I can take to reduce the risk?

 

Cheers everyone

[RDspaguy]

2 minutes ago, Skippyb said:

what would cause foam to shrink?

Time. Maybe chemical formula of the foam. I don't know, I am not a chemist, just a spa repair guy. But take the sides off of a mid-90's Sundance and you will see every surface between the wood supports is concave up to a few inches, and most of the 3/4" glue fittings will be leaking. 

[cjcarl]

I know this is an old conversation but I just finished tearing apart a jacuzzi tub that was left to winter with water in the pipes. All of the PVC exploded. I'm in New England. But I got it free, so I gave it a shot. 

This tub is insulated with closed cell on all fittings and plumbing and against the tub itself. And the rest is open cell to fill the gaps. It took probably 4 hours to tear it all out and clean the fittings, peel away the closed cell from the hose and pipes and prep it for repairs. I've never done any of this, mind you, and it was all about watching youtube vids and learning as we go. 

I then replaced ALL of the main plumbing lines. This took a few hours. with more hours just researching how and what to do. 

My friend and I then flipped it over and filled it, suspended above the ground on blocks. Not even a tiny drop of water came out after a day (we put clean rosin paper below. 

Spray foam is not just "maybe" better. It is unequivocally better. I built a passive house (high efficiency home with pretty much zero air flow and impossibly low energy costs. Foam was the key, done very similarly to how it's done in a tub. There is no better R-value in potentially wet areas than foaming. 

And if you just suck it up and give yourself a weekend or two, you can fix the leaks yourself. It's not that hard to do if you have a friend who shares your adventurous spirit. 

Not only that but in the process you learn just how basic ALL of the parts of a hot tub are. They're like dishwashers, they look all different but when you get into it, there's only a few expensive parts, most of them are the same from model to model, and they're pretty easy to figure out.