Green board’s kinda like that friend who’s reliable at parties, but you wouldn’t trust them to watch your dog for a week. I’ve used it plenty behind vanities and in spots where things might get a little steamy, but not soaked. Once tried it behind a tub surround (with a waterproof membrane over it), and yeah, it survived, but I still felt nervous every time someone took a long shower.
Cement board is a beast—no doubt about that—but lugging those heavy sheets up a narrow staircase just to cover the wall behind the toilet? Felt like overkill. I guess it comes down to how much risk you’re willing to take. If water ever does sneak through, green board’s not gonna save you from mold city. But for dry-ish zones, I haven’t had any callbacks... yet. Maybe it’s all about knowing your bathroom’s quirks and picking your battles.
I totally get the cement board struggle—hauling those sheets up stairs is a workout nobody asks for. I’ve been in the same boat, weighing risk vs. effort. One thing I always wonder: has anyone actually had a green board wall fail in a “dry” bathroom zone, like behind a toilet or vanity, assuming no leaks? I’ve only ever seen issues where there was an actual water event. Curious if it’s just luck or if green board really does hold up as long as it stays mostly dry.
I’ve wondered about this too, honestly. I’ve pulled out green board from a 90s bathroom reno—behind the vanity, not a hint of mold or mushiness, just some dust bunnies and a few old toothpaste splatters. That wall had seen its share of steamy showers, but no leaks. On the other hand, I did see one spot behind a toilet where the wax ring failed and water got under the baseboard… green board turned to oatmeal in that patch.
I guess it comes down to how “dry” your dry zone really is. If you’ve got kids who treat the sink like a splash pad, maybe it’s worth overbuilding. But for most adult bathrooms, I haven’t seen green board fail unless there’s an actual plumbing issue. Curious if anyone’s ever regretted skipping cement board in those spots, or if we’re all just playing it safe because we’ve heard horror stories?
Never had green board fail on me in a “dry” bathroom zone either, unless there was a leak. Like you said,
—that’s exactly what I’ve seen when water sneaks in. I’ve always figured cement board is overkill behind vanities or toilets unless you’re expecting a flood. For showers or tub surrounds, though, I don’t mess around. But for the rest? Green board’s held up just fine in my experience.“green board turned to oatmeal in that patch”
I’ve always figured cement board is overkill behind vanities or toilets unless you’re expecting a flood. For showers or tub surrounds, though, I don’t mess around.
I get where you’re coming from, but I’ve actually seen green board bubble up behind a vanity once, even though there wasn’t an obvious leak. Maybe it was just a super humid bathroom or someone spilled water and didn’t notice. I know it’s not supposed to happen, but after that, I started using cement board in spots where I thought moisture might linger. Probably overkill, but it gave me peace of mind. Guess it depends on how cautious you want to be.
