[dpach]

Starting some research on doing a bathroom remodel and we originally thought about a 3-piece fully enclosed tub and surround from Mirolin (enclosed top which would need to have an enclosed area between the tub surround top and the ceiling).

Then the wife came home one day and said 3 of her coworkers said they had one-piece enclosed with the drop down ceiling that goes from the front of the tub top up to the ceiling and they all had musty smells. When they remodelled, they all found the open cavity above the tub enclosure full of mold. The contractors said the enclosed tubs/surrounds tend to get moisture/humidity behind them and since the top foot or so from the enclosure to the ceiling is enclosed behind drywall, there's no air movement up there and the trapped humidity causes the mold. So all three families redid the tub surround in full tile (including ceiling).

The 3-piece from Mirolin we are considering is one where there is the tub, the middle section on top of the tub and the top enclosure that sits on top of the mid section (as compared to the 3-piece surrounds that are three pieces around the tub walls). I can see that perhaps humidity could get through where the pieces "snap" together, but has anyone had this experience before?

Would it pay to put two vents (one at each end of the front facing wall between the top of the tub surround and the ceiling) for air to flow in and out of the open space for ventilation when the ceiling fan is running?

Hope this makes sense and I would appreciate any feedback. The alternative is to fully tile the surround and ceiling with KERDI barrier and ceramic tiles (but hate the tile maintenance with preventing mildew on grout, etc).

 

[Just Bill]

One properly sized fan located close to or in the shower(approved for damp areas) is usually good enough to keep mold problems in check. One piece tub/shower units must be intalled and then the house is built around them. This is not a remodel option. The 3 pc unit sounds doable, Sterling has a similar unit, easy to install, no caulking required. An alternative to tile is solid surface in sheet sizes. The only joints are at the corners, which does require careful caulking, but considerably reduces cleaning issues.

 

[Blondesense]

Then the wife came home one day and said 3 of her coworkers.... When they remodelled, they all found the open cavity above the tub enclosure full of mold. The contractors said the enclosed tubs/surrounds tend to get moisture/humidity behind them and since the top foot or so from the enclosure to the ceiling is enclosed behind drywall, there's no air movement up there and the trapped humidity causes the mold. So all three families redid the tub surround in full tile (including ceiling).

For mold to thrive, it needs moisture and food. To minimize the moisture you want to install a properly sized fan. It is also a good idea to put it on a timer so it will run an additional 10 to 20 minutes after a shower.

Mold's most common food in a bathroom is the drywall paper. There are mold or moisture resistant drywalls, (often called greenboard or blueboard) but they are not mold proof. Cementboard isn't quite as easy to work with as drywall, but it has no paper, and so nothing for the mold to eat. You might consider using it behind the shower.