Drywall Installation Guide
Best Drywall for Bathrooms in Louisiana's Humid Climate
In a humid region, ordinary paper-faced board in a bathroom is a repair scheduled a few years out. Here is what belongs where.
Published August 2026 by Shreveport Drywall Pro
Why this matters more in Louisiana
Every bathroom is humid. What makes this region different is that the bathroom rarely gets a chance to dry out, because the air outside it is humid too.
In a drier climate, a bathroom spikes to high humidity during a shower and then returns to a low baseline. Here the baseline is already high for much of the year. The EPA recommends keeping indoor humidity between 30 and 50 percent to limit mold growth, and a Gulf South bathroom without good ventilation sits above that a great deal of the time.
Paper-faced drywall is an excellent substrate for mold in those conditions. The paper is organic, and the wall cavity behind is dark and still.
The four options, and where each belongs
Standard drywall
Paper-faced, cheapest, correct for a powder room with good ventilation and no shower. Not appropriate on any wall around a tub or shower in this climate.
Moisture-resistant board, the green stuff
Paper-faced but treated with a water-repellent core and facing. Better than standard in damp rooms, and a reasonable choice for bathroom walls and ceilings away from direct water contact.
The important limitation: it is moisture-resistant, not waterproof, and it is still paper-faced. Sustained wetting will still break it down, and the paper is still organic. Building practice has moved away from using it directly behind tile in wet areas for exactly this reason.
Mold-resistant board
This is the meaningful upgrade for a Louisiana bathroom. It replaces the paper facing with a fiberglass mat or a treated inorganic facing, which removes the food source mold needs rather than merely slowing water absorption. Products in this category are typically rated under ASTM D3273 for mold growth resistance.
It costs more per sheet than standard board. Against the cost of opening a bathroom wall in five years, that difference is small.
Cement backer board
Not drywall at all. A cement-based panel that is unaffected by water and is the correct substrate directly behind tile in a shower or tub surround. It has no organic content, so there is nothing for mold to feed on.
Cement board is not a finish surface. It is a tile substrate, and it needs a waterproofing membrane over it in a shower.
What goes where
| Location | Use | Why |
|---|---|---|
| Directly behind shower or tub tile | Cement board plus membrane | Continuous water exposure, no organic content |
| Bathroom walls away from the wet area | Mold-resistant board | High ambient humidity, splashing |
| Bathroom ceiling | Mold-resistant board | Steam collects here first |
| Wall shared with a shower on the other side | Mold-resistant board | Vapour migrates through the assembly |
| Laundry room | Mold-resistant board | Supply lines plus humidity |
| Powder room, no shower, well ventilated | Standard board is acceptable | Low sustained humidity |
The part no board fixes
Board choice buys you resilience. It does not solve a ventilation problem, and in this climate ventilation is usually the real variable.
An exhaust fan needs to actually exhaust outdoors rather than into the attic, which is a surprisingly common defect and one that pushes bathroom moisture straight into the attic where it condenses on the underside of the roof and on duct lines. That is the same mechanism behind a great deal of ceiling staining blamed on roof leaks.
It also needs to be sized for the room and to run long enough to clear the moisture, which generally means several minutes after the shower stops rather than switching off with the light. A timer switch is a cheap upgrade that does more for a bathroom than a board upgrade does.
If you are repairing rather than rebuilding
When we open a bathroom wall in an older home here, ordinary paper-faced board is what we usually find, and often with mold on the cavity side that was invisible from the room.
In that situation the replacement should be mold-resistant board even if the rest of the wall stays. There is no benefit to matching the original specification when the original specification is what failed. It is a small upgrade at the point where the wall is already open, which is the cheapest moment it will ever be.
See water damage drywall repair for how we handle the moisture verification, and drywall installation in Shreveport for full bathroom rebuilds.
The bottom line
In a region this humid, ordinary paper-faced board in a bathroom is a repair scheduled a few years out. Mold-resistant board on the walls and ceiling, cement board behind tile, and a working extractor that actually vents outdoors.
If we are already opening a wall, Shreveport Drywall Pro will recommend upgrading the replacement rather than matching a specification that has already failed once. It is the cheapest moment that upgrade will ever be.
Remodelling a bathroom?
Tell us what is going where, especially behind the shower. We specify board type wall by wall in writing so nothing ordinary ends up somewhere wet.
Or call (318) 666-5548.
FAQ
Common Questions
Is green board enough for a bathroom?
For walls and ceilings away from direct water contact, it is acceptable. Behind tile in a shower it is not, because it is still paper-faced and moisture-resistant rather than waterproof. Cement board plus a waterproofing membrane belongs there.
What is the difference between moisture-resistant and mold-resistant drywall?
Moisture-resistant board slows water absorption but keeps a paper facing, which is organic and can still support mold. Mold-resistant board replaces the paper with fiberglass mat or a treated facing, removing the food source entirely. In this climate the second is the meaningful upgrade.
Do I need cement board on every bathroom wall?
No, only where tile meets sustained water, meaning the shower and tub surround. Elsewhere it is unnecessary, harder to work with and more expensive than mold-resistant board.
Will better drywall stop mold in my bathroom?
It removes the food source in the board itself, which helps considerably. It does not fix a ventilation problem. If the exhaust fan is undersized, vents into the attic, or switches off with the light, moisture will still accumulate.
Is it worth upgrading when repairing one wall?
Yes. The wall is already open, which is the cheapest moment the upgrade will ever be, and matching an original specification that already failed once makes little sense.