Out at the landsite where my cabin is, someone always has something to say about construction methods. I've already gotten an earful about drywall from some folks who have very strong opinions about it, and I'm not even at that stage yet.

These folks are particularly insistent that cabins which are left unoccupied for weeks at a time MUST use greenboard or other mold-resistant drywall and only that. Milam county isn't really a place where it gets so humid that mold should be a problem on walls, so I don't exactly see the rationale for their insistence. In all of my projects in my life, I've never used greenboard in an application that was not a bathroom or kitchen backsplash.

That being said, I have had to treat some existing mold with Concrobium as I've opened up the walls. Other than that, I don't see a compelling reason for the added expense.

Is there some justification I'm missing here? In the end, we're only talking about 14 or 15 sheets, anyway.

jt2hunt said:

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Whether or not it's needed. The amount of drywall that you need for that space is so small and insignificant to the cost of the project. Why not just put the green board up that way you don't have to deal with answering the questions or dealing with the complaints from those around you in that community?

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That's generally my inclination, but I'm always interested in learning from folks on here when there's something I might not know.

Will you be getting a lot of vapor in your walls or subfloors?

jt2hunt said:

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Will you be getting a lot of vapor in your walls or subfloors?

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Not planning on it. I've also added Tyvek housewrap during the renovation.

Seems like scraping burnt toast versus moving the knob. I'd be more concerned with getting it dried in well.

I'd also suggest it isn't humidity which is the issue but rather that humidity condensing on something to create mold, a la leaky building having hot humid air hit conditioned air and getting a glass of iced tea sweating in a wall cavity. Seems like all the mold issues we saw in schools once upon a time were wall details failing. Like a Yankee architect doing three schools in South Texas, what do you mean it's sweating?

Anecdotally, double wide at a friend's family ranch is empty through the summer in Kimble county. 20+ years old and drafty, and it ain't covered in mold.

I might suggest responding by explaining you opted for a seamless vapor barrier and based on responses you'll hear pretty quick whether they understand building science or just have a loud brother in law.

Or think of it this way. If you left a Yeti/RTIC/Kodi out there, are you gonna find mold in it? Not when it's insulated and sealed. And dry.

You should top them and use densglass or similar.

In commercial construction, I almost exclusively use greenboard for interiors now. It's just easier to know that you have some built in mold protection when you're rocking in an uncontrolled environment and the cost delta is negligible.

UnderoosAg said:

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Seems like scraping burnt toast versus moving the knob. I'd be more concerned with getting it dried in well.

I'd also suggest it isn't humidity which is the issue but rather that humidity condensing on something to create mold, a la leaky building having hot humid air hit conditioned air and getting a glass of iced tea sweating in a wall cavity. Seems like all the mold issues we saw in schools once upon a time were wall details failing. Like a Yankee architect doing three schools in South Texas, what do you mean it's sweating?

Anecdotally, double wide at a friend's family ranch is empty through the summer in Kimble county. 20+ years old and drafty, and it ain't covered in mold.

I might suggest responding by explaining you opted for a seamless vapor barrier and based on responses you'll hear pretty quick whether they understand building science or just have a loud brother in law.

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The only issue I see is that your argument contradicts itself. A seamless vapor barrier only works on your suggestion if it doesn't fail. And in the environment we're talking it's probably going to do so at some point. Between limited use (which generally means less maintenance or chance to catch issues quickly) and all the nature (rodents, etc.) it's going to get compromised at some point.

What your nosy neighbors are trying to convey horribly is it isn't about what should happen or building practices. It's about the knowledge of vacation properties not getting the same level of use or dehumidification from AC (and therefore maintenance) and installing a fairly cheap material now avoids ripping everything out later like they've probably seen over and over.

At Home Depot pricing we're probably talking about less than a $200 difference max.

If it is not going to be climate controlled year around then I would use green rock. I have seen situations unfold where mold started growing when the ac was turned off for a very long time and the house remained closed up. One was on a rental during Covid where the students turned the air to off and left for March to June and came back to a disaster. The other was only a house that people moved out of and turned the ac off and after about 6 months it was on everything inside. Neither house had any water leaks to cause this issue.

JP76 said:

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If it is not going to be climate controlled year around then I would use green rock. I have seen situations unfold where mold started growing when the ac was turned off for a very long time and the house remained closed up. One was on a rental during Covid where the students turned the air to off and left for March to June and came back to a disaster. The other was only a house that people moved out of and turned the ac off and after about 6 months it was on everything inside. Neither house had any water leaks to cause this issue.

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At a minimum I will be in there once a month, but once the minisplit is installed I will keep it conditioned to 85 when vacant in the summer and 62 (the lowest possible) in winter. However, it was vacant and unconditioned for almost 2 years and the only mold issues were inside the walls from water damage.