Basement Spa - Stuck on Humidity Issue

[quirt9099]

Newbie.  I've done research on the topic but now I need an opinion from knowledgeable people, and that's why I'm here.

I badly need a spa for physical therapy.  Pretty much settled on the Sundance Capri.  Thing is, I want to put it in my poured concrete, open, unfinished walk-out basement.  Space isn't an issue (ceiling's almost 10 feet, with vapor barrier fiberglass in the ceiling bays), but I am concerned about humidity.  (Five years ago I discovered mold on the plywood sheathing of the exposed sides of the house, the result of our builder putting unfaced fiberglass into those bays. Needed mold remediation, guys with the moon suits, etc.  The basement walls are now properly insulated.  But I remain spooked.)

Here's where I'm stuck.  I'm trying to figure out what I need to do to make this happen without humidity concerns.  There just isn't that much out there I can find on indoor spa considerations, other than building a dedicated room.  Dealers I've spoken with just say "huh?" when I ask them questions on this matter, I guess because most spas go outside.  I've seen article references to "indoor hot tub contractors" but several dealers I've spoken with weren't even aware there was such an animal.  I'm not competent to evaluate and allow for considerations such as air and water temp, surface area of the water, basement humidity level, cover insulation efficiency, and so on.

I have a remodeler coming over in a few days to talk about building a, well, not exactly a room, but an enclosure for the spa.  And I'm looking into dehumidification systems and exhaust options.  Thought I had some kind of handle on this, until I talked to a tech at a custom spa cover place in Texas.  Told her the situation and mentioned that I would be the only person using the spa, and it would be used only about two hours a day, max.  She said, in effect, if you have a good cover on the spa, insulated in the seam, skirt extending down a few inches, a few other things, there shouldn't be a problem.  You don't need to build an enclosure or install an exhaust system, she said.

So, I wonder if I've been overanalyzing this.  Do you folks have an opinion on how I might proceed based on what I've said.

[Zep]

Click link below:

http://www.nationaljewish.org/news/y2000/news49.aspx

[Pathfinder]

Whether you decide to build a small enclosure or keep it wide open, Installing a large CFM rated exhaust fan will help greatly. Panasonic IMO makes the best rated units. In a side by side comparison    we did at the plumbing store I worked at the Panasonic killed the Broan unit that had the same CFM rating.  

Besides installing the exhaust fan  you may also want to look at installing a Humidistat sensor that connects to a whole house dehumidification system. This way you can set up zones for your whole house and have a certain setting just for your basement. This way you wouldnt have to build a room.

I recently joined my pool & spa company with my buddies HVAC company and we had a someone call with moisture issues and after inspection we noticed a damp basement as well so we installed a system that connected right into his existing duct work.  So I am learning more and more about ventilation.   Lastly  did you go through your insurance company for your mould abatement?? The reason I ask is if you did they may not allow you to have a tub in your house even if you take all precautions bc of the previous mould issue.

[Cyn]

You really think you will be using the tub for 2 hours a day?  And would this be 2 hours straight?  You can put in a good sized regular tub with great therapy jets for a lot less money and without the worry of mold or the cost of a special room.  

[Chas]

Lots of options. First, don't worry too much about lung diseases if you keep the water well sanitized. Also, good ventilation will make using the tub more enjoyable - and safer.

There is already a room in your house which is built specifically for this type of use - your bathroom(s). Take a look at them, and consider building something similar in your basement. Adding some walls, using blue/green drywall, painting with gloss or semi-gloss enamel with a mold killing additive is nothing new. You have lived with a room like this all your life, we just don't think of it.

As to dehumidifying - for recreational use I would say that simply changing the air is all you need. However, you are talking about more than recreational use. You may very well need to dehumidify. There are many ways to accomplish this. You can simply wire in a GFI-protected outlet and roll in a portable unit. They work, but tend to put off a bit of heat, which you will have plenty of already.

You could install a simple window Air conditioner. These don't have to be installed in windows only, they can be put right through the wall for a cleaner look and more flexibility in layout. If you go this route, be sure to buy one with electronic controls wo you can set it and forget it - opening the lid of your tub will raise the temp of the room and it will kick on all by itself. When you are done, it will run until the room is cool again, which should equal 'dry' as well.

Don't forget the aesthetics of using the tub in a small enclosure: putting in a couple of glass panels will allow you to see out to the basement and hopefully out of doors if the arrangement of the floor plan allows. Also, the glass makes it very obvious if you are moving enough air to keep things dry (and safe) by simply fogging up or not. You don't have to buy expensive windows, a simple pane of glass set in a frame works well, and can be matched to the rest of the trim in the room. Or, depending on who is doing the work, it might actually be less expensive to buy some basic, single-pane windows at the DIY center. Of course, if the window is in an outside wall, it should be vinyl, double-pane.

And finally - plan for changes. I have put in several rooms like this for clients over the years, and we always allowed for changes. What I mean is that we started with a pair of large, quiet bathroom fans ducted outside. But we built in such a way that  there was room for a larger air handling unit and larger ducting. That was installed in such a way that AC could be added to completely control the room - both temp and humidity.

I did one on a tight budget and we simply put in lots of windows arranged to catch the prevailing breezes. It worked, but might not be possible for your case.

HTH

 8-)

[Repeat_Offender]

The key is MAKE-UP AIR. In addition to the large quantities of exhaust needed to prevent mold/mildew damage that would surely occur at that high humidity level, you need to replace the exhausted air with an equal amount of conditioned air. Not an inexpensive proposition. That is why you only see indoor pools and spas in hotels and very expensive homes where specialized make-up air equipment is specified and budget is not an issue.

[Zep]

"That is why you only see indoor pools and spas in hotels and very expensive homes
where specialized make-up air equipment is specified and budget is not an issue"

RepeatOffender thats some good information. Plus I always notice a distinct odor
in the indoor pool rooms even in hotels and fitness centers and that is not an odor
I would want anywhere in my house. I am no expert, but I would think placing a
steaming hot tub in a basement would really exacerbate the problem of odor/moisture/mold/ect?

ps: being from Dallas, Texas (no basements) how does one get a hot tub delivered into a home basement?

[Chad]

He has whats called a "walk out" basement. This means that the floor of the basement at the rear of the house is at the same ground level as the earth outside. And therefore a door can be installed to exit/enter the basement. I'm assuming he has a "double door" unit that is not seperated by a frame in the middle.

[Chas]

In this case it would make sense to draw the makeup air from the basement to keep it dry as well.

Draw the air from the basement, through the spa room and then out.

 8-)

[quirt9099]

Knew I came to the right place.  Great info here.  Thanks, everyone.  I have a much better idea of how to proceed if I go through with this.  To answer some questions:

Didn't go through the insurance company with previous mold problem.  The builder came around and footed the cost after a heart-to-heart.

Two hours a day in three sessions.  Problem with a bathtub arrangement is using all that water.  And heating it.

Chad's description of my walk-out basement is accurate.  But I have a regular door, not double doors.  That's why I'm looking at the Capri, (5'9'' x 6'10' x 30.5").

A reputable builder is coming over tomorrow to give me his take.  I'm going to tell him what you all have said.

[quirt9099]

Forgot to add one interesting thing:

The other day, I talked to a tech--not a salesman but a tech-- who works for a spa cover manufacturer.  I told this person exactly what I said in my first post, and the response went something like this: the key is to get a quality cover, long skirt, insulated in the seam.  If you do that, and you use the spa two or three times a day for a couple of hours, then you don't need to build an enclosure or invest in a fancy dehumidification system.  Monitor the humidity level, use room dehumidifiers as needed.  What escapes from the spa when a proper cover is on is negligible.

That's an interesting take, isn't it, and this person spoke authoritatively.

[Pathfinder]

This issue is never about humidity with the cover on at all. Its when the cover is off and you are planning to use it multiple times, there's no way a little portable unit will keep up. Its amazing how much they collect without a tub. With your tub use schedule your adding at least 10x the humidity and you dont have any air movement in the upper part near the ceiling.  So I will have to disagree with what the cover guy said.

[Zep]

wish this guy would try the spa outdoors first

2 years from now 50/50 he regrets putting a hot tub in a basement

but hey 2EachHisOwn!

[Chas]

you don't need to build an enclosure or invest in a fancy dehumidification system.  Monitor the humidity level, use room dehumidifiers as needed.  What escapes from the spa when a proper cover is on is negligible.[/i]
That's an interesting take, isn't it, and this person spoke authoritatively.

Having actually INSTALLED a few of these over the years, I would say that is not an accurate take...


 8-)

[quirt9099]

Having actually INSTALLED a few of these over the years, I would say that is not an accurate take...

8-)

Builder just left.  He noted the ten foot ceilings, the bone-dryness of the basement, and the insulation.  He doesn't think a dedicated room has to be built, suggesting similar things to what I read here: exhaust fans over the unit(but not whole-house powerful) vented through the siding; diverting some heat to the basement; monitoring humidity and room dehumidifiers as needed.  He seems to think that given the limited time the unit would be uncovered, there wouldn't be an issue.  If it became one, the enclosure could be built.

Mulling it over, I keep coming back to Chas's comment.  I don't have a good feeling about what that tech said about covers and humidity, either.