Spa Pads

[Mr. Ed]

I asked this question as part of the discussion of foundations, but didn't get a reply, so here it is again. I've seen several ads for "spa pads." Six of them, interlocked, make a 96" x 96" foundation. They cost about $300. They look quick, cheap and easy to move if you decide to move your tub. They also look like they might add a little insulation, too.

Which suggests another question: does insulation under a tub do any good. Before someone tells me that heat rises, just think about going camping without your ground pad or air mattress. Here in Minnesota our frost usually goes into the ground four or five feet-enough to freeze in under the center of a large tub. I'm thinking now that a couple of sheets of 2" closed cell foam under a tub might be a good idea. Has anybody tried it?

[Brulan1]

I asked this question as part of the discussion of foundations, but didn't get a reply, so here it is again. I've seen several ads for "spa pads." Six of them, interlocked, make a 96" x 96" foundation. They cost about $300. They look quick, cheap and easy to move if you decide to move your tub. They also look like they might add a little insulation, too.

Which suggests another question: does insulation under a tub do any good. Before someone tells me that heat rises, just think about going camping without your ground pad or air mattress. Here in Minnesota our frost usually goes into the ground four or five feet-enough to freeze in under the center of a large tub. I'm thinking now that a couple of sheets of 2" closed cell foam under a tub might be a good idea. Has anybody tried it?

Depends what kind of bottom the tub is made of. Is it wood? Forever floor/ABS pan? If that closed cell foam gets wet after a while do you think it will freeze? I dont think its a great idea but I also dont think it will hurt.

[spatech (the unreal one)]

I asked this question as part of the discussion of foundations, but didn't get a reply, so here it is again. I've seen several ads for "spa pads." Six of them, interlocked, make a 96" x 96" foundation. They cost about $300. They look quick, cheap and easy to move if you decide to move your tub. They also look like they might add a little insulation, too.

Which suggests another question: does insulation under a tub do any good. Before someone tells me that heat rises, just think about going camping without your ground pad or air mattress. Here in Minnesota our frost usually goes into the ground four or five feet-enough to freeze in under the center of a large tub. I'm thinking now that a couple of sheets of 2" closed cell foam under a tub might be a good idea. Has anybody tried it?

I've seen those interlocking pads and they're ok. I prefer the 1 pc or 2 pc pads that have that "Rhino lining" type exterior if you're looking for a portable pad.

You do want to be sure there is no air transfer on the bottom of the spa so if it is insulated there you'll be in good shape and ignore the people that tell you that's not important because heat rises. Personally, I wouldn't put any 2" close cell foam under the spa. If you buy a well made spa that uses PT wood or has a base pan it should be just fine right on top of your pad.

[jeff grotte]

I asked this question as part of the discussion of foundations, but didn't get a reply, so here it is again. I've seen several ads for "spa pads." Six of them, interlocked, make a 96" x 96" foundation. They cost about $300. They look quick, cheap and easy to move if you decide to move your tub. They also look like they might add a little insulation, too.

Which suggests another question: does insulation under a tub do any good. Before someone tells me that heat rises, just think about going camping without your ground pad or air mattress. Here in Minnesota our frost usually goes into the ground four or five feet-enough to freeze in under the center of a large tub. I'm thinking now that a couple of sheets of 2" closed cell foam under a tub might be a good idea. Has anybody tried it?

it is not going to hurt. it might help.

I have lived in minnesota 43 of my 47 years.

Jeff Grotte

PS my last tub sat on gravel.

the one before that plywood.

before that concrete.

we have installed them on raised wood decks.

my cheapest garage to heat 1000SQ ft 10,000 cu ft had 2" foam under and up the sides, it took 2 1500watt heaters in the middle of winter to heat.

like i said it will not hurt. and it might help

[Mr. Ed]

Depends what kind of bottom the tub is made of. Is it wood? Forever floor/ABS pan? If that closed cell foam gets wet after a while do you think it will freeze? I dont think its a great idea but I also dont think it will hurt.

Closed cell foam sheets are used for in-ground heating applications. Dig a trench and put in sheets of foam edgewise (i.e., 4 feet down) in a continuous perimeter around your floor. Put electric coils or pads or hot water pipes under the floor, and you have a very comfortable and cheap-to-run heating system. My point is that the foam can take all the water that mother nature can dump off the eves of your house or garage. Good foam just doesn't absorb much water, doesn't compress and doesn't lose its R value. I would think it would prevent heat conduction to the cold ground under a tub if it were applied right. Some one out there must have tried it or maybe those spa pads do the same thing. Mr. Ed

[SmilinBare]

Which suggests another question: does insulation under a tub do any good. Before someone tells me that heat rises, just think about going camping without your ground pad or air mattress. Here in Minnesota our frost usually goes into the ground four or five feet-enough to freeze in under the center of a large tub. I'm thinking now that a couple of sheets of 2" closed cell foam under a tub might be a good idea. Has anybody tried it?

Good question! I think your later post suggestion installing it vertically is the way to go. Can't hurt. If, on the other hand, you place your tub directly on those coupla sheets of closed cell (styrofoam?), it may (I'm guessing) affect the stability of the tub, maybe?

The tub I got has what I think is closed cell polyurethane sprayed on the bottom and inside perimeter walls of the wooden tub enclosure to a depth of a couple of inches. I'm guessing that's providing an R value of 10.

Unfortunately, although minimal in width, there are multiple 1/4 - 1/2" gaps in the foamed walls where the access panels are separated from the spa enclosure body. In my case, I'm more interested in tightening up those gaps to cut down on the heat leakage and cold air infiltration, there.

I have a friend who HAD (past tense. he moved away and left his tub) a tub recessed in a high deck where the bottom of the tub was still 8' above grade. Since the walls and bottom of his tub were out of sight, he made up a frame and some big panels of 2" pink insulation board with which to surround his tub and cover the bottom.

[Brulan1]

Good question! I think your later post suggestion installing it vertically is the way to go. Can't hurt. If, on the other hand, you place your tub directly on those coupla sheets of closed cell (styrofoam?), it may (I'm guessing) affect the stability of the tub, maybe?

The tub I got has what I think is closed cell polyurethane sprayed on the bottom and inside perimeter walls of the wooden tub enclosure to a depth of a couple of inches. I'm guessing that's providing an R value of 10.

Unfortunately, although minimal in width, there are multiple 1/4 - 1/2" gaps in the foamed walls where the access panels are separated from the spa enclosure body. In my case, I'm more interested in tightening up those gaps to cut down on the heat leakage and cold air infiltration, there.

I have a friend who HAD (past tense. he moved away and left his tub) a tub recessed in a high deck where the bottom of the tub was still 8' above grade. Since the walls and bottom of his tub were out of sight, he made up a frame and some big panels of 2" pink insulation board with which to surround his tub and cover the bottom.

Having an ABS or forever floor on a tub can prevent the hassel of trying all these things to save a dollar.

[Mr. Ed]

Having an ABS or forever floor on a tub can prevent the hassel of trying all these things to save a dollar.

When I started my research on tubs, I had no idea that there are as many options as there seem to be. Tell me about ABS and forever floors. ABS sounds waterproof, but thin. Does it have any insulation value? I'm concerned about conductive heat loss to the ground. Or, to put it another way, I don't want my hot tub to keep the ground from freezing! Mr. Ed

[Brulan1]

When I started my research on tubs, I had no idea that there are as many options as there seem to be. Tell me about ABS and forever floors. ABS sounds waterproof, but thin. Does it have any insulation value? I'm concerned about conductive heat loss to the ground. Or, to put it another way, I don't want my hot tub to keep the ground from freezing! Mr. Ed

Hay mr. ed, I know the Coleman spa puts a 1/2" foam and thermal lock or foil barrier to prevent that heat loss and they call it the ABS pan and some call it the forever floor(Artic mabye) and they do the same thing I think. It adds to the Rvalue in general.