Best Practices in Mold-Resistant Bathrooms
I have looked at a variety of best practices in mold-resistant bathroom strategies and materials for a moderate size full bathroom. I have landed on the following:
For materials, a project must use a non-paper faced wall covering such as a gypsum board faced with a fiberglass laminate/coating for the entire bathroom (Densarmor is one product example). A mold-resistant, paper-faced product like Greenboard would not suffice. Concrete board should be used to back behind the tub and floor if tile is being used. A full piece fiberblass tub/shower does not need to be backed with concrete board although it will need an air barrier with insulation behind it if it is on an exterior wall (I think an air barrier should be required for interior walls as well).
For a ventilation, the project should meet the requirements of ASHRAE 62.2-2010 and require 50 cfm of intermittent bathroom exhaust to the outdoors (or 20 cfm of continuous exhaust). The fan should be tied to the main light switch and the light switch or fan should be equipped with a delay off timer set to at least 15 minutes. This will allow for the fan to continue running once the light has been switched off and the resident has left the bathroom.
Now I know there are a thousand ways to skin this cat, but I would really love some feedback on best practices that are not only effective, but low-cost and applicable in the field. Please specify the climate zone(s) you are thinking about when suggesting a best practice. San Diego is not New Orleans or New York City and vice versa. Also, if you have recommendations, please suggest ones that don’t rely on the resident’s good behavior.