Insulate behind tub surround

[Justintime]

I recently bought a tub surround from a local store and need advice on how to properly insulate behind the walls. I have one exterior facing wall and the rest are interior. I plan on installing the surround direct to stud with green board (actually purple) in the space above the walls. There is a bedroom on the other side of the tubs back wall that I would like to insulate against noise. I also don't want the wall facing the exterior wall to be too cold to the touch. Any suggestions would be appreciated. Also on a separate topic has anyone install one of these surrounds direct to studs? Are decking screws or nails preferred to install the walls.

[Mamba]

I am no pro, but I did replace an existing bathtub with a 3-piece surround shower a few years back. I used the insulation materials that were available to me - a 1.5" layer of styrofoam (was found in interior wall) plus a layer of fiberglass insulation (R11 if memory serves). On the exterior wall (cold climate) I used R16 - again if memory serves.

I have no problems with sound - the side wall of the shower backs on to the headboard wall of our bedroom, and very little noise is apparent.

FWIW, I would never use nails as a fastener for these units. Ours was fiberglass, and a missed hammerstroke could crack it badly. I drilled and put in stainless screws with padded washers. I only used a few, and the unit is very stable and solid. I beleive ours was mounted over the wetrock except where the tub had been.

Cheers Gary

[Oren]

I removed a seven year old fiberglass shower pan. Sheet rock screws were initially used and failed, rusty and heads off.

Pre drill and used a stainless screw.

-- Oren

[hallerb]

fiberglass doesnt insdulate well when moist.

closed cell expanding foam is the best material R6 or better per inch. plus it seals all the air leaks so it minimizes noise too

[Oren]

fiberglass shower pan, not the wall insulation ...knock, knock!

-- Oren

[Joseph Meehan]

In general you want to block air exchange. Air caries sound very well. (Try opening your car's window as a train is going by.)

Next you want weight. Heavy things (drywall lead sheets etc.) block sound well.

You also want to prevent any direct solid connections. Stagger wall studs or use special isolation devices to keep the sound from traveling through the wall (remember the two cans on a string (well wire actuarially worked) you want to break the wire).

Filling in wall cavities with sound absorbing materials (acoustical fiberglass bats) will do a little.

Supply and drain lines are also sources of noise. Be sure to address them.

[marson]

We insulate the exterior wall next to the tub with fiberglass. We install a 6 mil poly vapor barrier, and cover this with plywood to prevent it from flapping when, for example, people open and close doors. Haven't heard that sound between the shower and the bathroom is a big concern. All I can ever hear is the sound of water running. Since the tub only contacts the studs in one spot basically, that probably helps. I bet if you put resilient channel behind the rock above the tub, and insulated the wall with fiberglass, that would be sufficient. You aren't building a recording studio after all.

If you keep the caulking in order, regular galvanized deck screws will outlast the fiberglass tub.

[bigang54]

use roofing nails..the heads are flat and wont stck out too far..

[hrhofmann]

It's been 8 years since the OP, I hope he/she has had a bath by now.