I have a buddy building a new house and the guys that did the drywall didnt use green board in the bathrooms. We live in iowa. Is it code to put greenboard in the bathrooms in iowa i cant seem to find it if there is
It's not required, and in my opinion it's pointless. If enough water gets through your paint that you're depending on the drywall for containment you have bigger issues. Good quality primer and paint accomplish the same thing, and if you're installing tile you probably want cementboard anyway.
The Code says bathroom finishes must be hard, smooth, non-absorbent, and not adversely affected by moisture, except in private dwelling units. (See ICC 1210.2.2)
Showers shall be smooth and non-absorbent up to 70” above the drain, if a shower head is installed. (ICC 1210.2.3)
In most places I have worked, the green board is only required on walls around tubs and showers, not the entire bathroom, and not if using a pre-fab tub or shower enclosure.