Esteemed whirlpool tub gurus:
I’m getting ready to install a whirlpool bath in a second floor bathroom above a dining room. As part of my preparations, I’m expecting to have to sister new joists to the c. 1913 ones (I’ve seen them from underneath during a ceiling repair!); while I’m at it, and before I install the subfloor (3/4″ plywood in anticipation of 3/4″ hardwood) I wanted to make every effort to isolate the sound of the motor and pump.
I’m open to any and all ideas, both in terms of filling the voids between joists, and in terms of isolating the tub from the subfloor.
Looking forward to your sage advice, as usual,
–Olsh
Replies
I put one in my inlaws house, but did not have to worry about sound proofing because it was over a basement. I did set the pump and motor on cork/rubber pads that I get from an HVAC supply house. The motor and pump are the primary source of noise, but filling the tub has proven to be noisey too. Maybe some foam under the tub ? You probably have cast iron DWV, and are going to make the tub connection with PVC, right? I would keep that connection as short as possible, insulate it and stay with the cast iron the rest of the way, it is a lot quiter than PVC.
Dave
I'd stuff the joist bays full of fiberglass, set the motor on rubber isolation pads, and also look at putting some isolation pads under any "feet" that the tub may have.
To keep the noise down even further, and to keep the heat of the hot water in the tub at the same time, shoot some spray foam under the tub (don't put too much, or you'll push the tub up- especially with fiberglass). Then pack the entire cavity between the tub and any platform framing with fiberglass. There's nothing worse than putting 80 gallons of hot water in a tub, and ten minutes later having it get cold. I think a lot of people think it'll be like a hottub, where the water stays hot constantly.
Two other "recommendations":
- Spring for an inline heater for the tub- it'll help keep the water hot longer, and probably pay for itself in water savings from not having to keep adding hot water.
- If the tub doesn't get used for a long period of time, fill it with cold water to just above the jets, and let the motor run for ten minutes or so, prior to filling with hot water. Nothing ruins a romantic mood like filling the tub, lighting the candles, and dimming the lights, only to have a bunch of black crud blow out of the jets when you turn them on. You'd be surprised how much gunk grows in the lines when you don't use the tub for a while (especially if it's plumbed with flex lines that sag in the middle- perfect place for growth).
Bob