We have a boiler system for our house. Currently in our bathroom which is only 5’ wide x 10’ deep and 9’ high we have two baseboards running along each wall. The bathroom is all ready small now put a tub, sink and toilet in there. Anyways I am going to be gutting the whole bathroom out and rebuilding it. The house is old and has about 1” oak as part of the sub floor. I am going to put down another subfloor (to make it level with the hall floor) and then stone on top of that. I would like to take the baseboard heaters out and run them underneath the floor as it is just a basement below which the ceiling is open. What I was thinking about doing is running the pipes below the floor and on one side have vents up to the bathroom so some of the heat will come up through the floor while the rest will be under the rest of the floor. My question is has anyone done this and does it work well enough? The rest of the pipes that run under the rest of the bathroom, will that even heat the floor if I am trying to go through all the layers? The lest question is there something I could use in the basement to cover up joist so the sound doesn’t travel to the basement (maybe just plywood or something else.

Thanks in advance.

 

I think your plan is poor. If you want a warm floor then instead of layering more wood on the existing subfloor use a thick bed of mortar into which you embed PEX tubing for a radiant floor.

This will take a bit of engineering to get enough heat through the stone finished floor without over heating it. It will be slow to respond so you will need more sophisticated control. The circulating water will need to be at a lower temperature than that used in the baseboards and / or radiators in the rest of the house and that also requires more controls.

You could possibly install a toe space heater if you have a vanity cabinet or even go so far as to use a toe space heater in the basement and duct a supply and return air passage to either the floor or into the walls. The toe-space heater would have quick response and use the same temperature of water as the rest of the system so it would be much easier to control.

As for limiting the sound transmission to the basement you can do several things. You can install unfaced fiberglass insulation, you can install soundstop fibreboard and you can install drywall. Any of these or a combination will help to reduce the sound transmission. Do NOT use plywood alone as it will likely act as a drumhead and amplify the sound.