Probably the biggest fear anyone has with their bathroom is mold.
And rightfully so.
My wife has bad allergies & asthma, and any exposure to mold can trigger terrible respiratory reactions.
This in turn can land her in the emergency room.
Even if you don’t have asthma or allergies, mold is likely something you’d prefer to avoid.
In this tutorial we’ll share several bathroom renovation tips that can keep your bathroom’s air quality in tip top shape.
So keep reading to gain more insight.
What’s the Best Backer Board
One of the best options for bathroom walls & ceilings is cement board.
Cement doesn’t contain any organic matter for mold to use as a food source.
Cement boards are usually sandwiched between two layers of fiberglass mesh, so there is no paper in the product.
I personally prefer using DuRock NextGen made by USG. But not all stores carry it.
Here in the United States, you can get DuRock at Lowes.
Keep in mind that cement board does require some type of waterproofing. RedGard is a great way to waterproof cement board.
You can also use Schluter KERDI-BOARD or Wedi instead of cement board.
Again there’s no paper for mold to consume. And these boards are easier to cut than cement board.
Most of the time I opt to buy Purple Board for the walls outside the shower.
Purple Board is a great option because its face is constructed from a mold & moisture resistant fiberglass mat.
National Gypsum is the manufacturer of Purple Board. It installs just like normal drywall and uses the same type of screws.
So whether you’re installing bathroom walls or hiring a contractor, these are the best wall panel options to consider.
They’ll eliminate the odds of having mold inside stud walls.
But the avoidance of an unsafe bathroom environment doesn’t stop with just the backer boards.
What’s the Best Type of Drywall Joint Tape
Installing cement board or purple board is very straight forward and is the first step in bathroom remodels.
The next move is to make these already strong surfaces one cohesive unit by using drywall joint tape and joint compound.
Joint tape needs to be used anywhere there’s a space between two consecutive bathroom wall or ceiling panels.
The picture below shows a great example of how purple board will look after it’s installed on the bathroom studs.
Even though this section is about drywall joint tape I want to point out that the purple board in the above photo is attached with coarse-thread drywall screws spaced every 8-10 inches apart.
If you have wood studs you’ll need to use coarse-thread drywall screws and if you have metal studs you need to use fine-thread drywall screws.
Since I mostly work with older homes I have a good supply of coarse-thread screws.
Okay, remember how we want to avoid paper in the bathroom since it’s like cheerios – a food source – for mold?
Joint tape comes in two different commonly used forms: paper or fiberglass.
If paper is bad for your bathroom wall panels then it’s not a good idea to use paper joint tape near the shower.
So this is why we used fiberglass drywall joint tape in Rob’s bathroom renovation (Rob is my brother-in-law, he’s a good guy who likes to make his own beer, which is awesome in so many ways!)
There is no chance mold will ever grow on fiberglass.
And the other nice part is it has a sticky self adhesive back.
So you can attach it directly to the drywall (unlike paper tape).
I centered the fiberglass tape over all drywall panel seams.
If you encounter a situation where there’s a wide gap (anything more than 1/4 of an inch) between two pieces of drywall you can fill the gap first with drywall compound.
Then, you can place the fiberglass drywall joint tape over the seam.
The picture below shows a section of drywall we installed to cover up the old mirror.
There’s a good 1/2 inch gap between the new drywall and old section of wall.
I pre-filled this gap with joint compound then applied the fiberglass joint tape.
The drywall panels are in place. You have your fiberglass joint tape covering all the seams.
The fun part is next: using drywall joint compound!!
Pre-Mixed or Setting Type Joint Compound
There’s nothing wrong with using pre-mixed drywall joint compound.
It has the correct consistency and comes in a bucket that you can lug around anywhere.
But I remember watching a great bathroom remodeling segment on HGTV with Mike Holmes.
He had this tip:
The long setup time for pre-mixed joint compound makes it susceptible for organic material to embed itself into the compound.
He also went on to comment how he’s seen mold form on top of the compound in the bucket after it’s sat around for a few days.
Now this probably isn’t typical but job sites aren’t exactly the cleanest places.
Let’s say someone is eating lunch next to an open bucket of joint compound and Dorito crumbs fall in.
BAM!! There’s your organic food source.
Also, pre-mixed joint compound doesn’t harden rock solid like setting-type compound.
Setting-type joint compound comes in a powder that you have to mix with water.
The bags will have numbers on them to indicate the time (in minutes) it takes for the compound to harden. I usually buy the bag labeled “45”.
Setting Type compound also comes in bags labeled “20” and “90”.
This means the compound will harden in 20 minutes or 90 minutes.
If you’re new to using joint compound I recommend using the “45” or “90”.
But if you only have a small patch job the “20” comes in very handy. It will literally be firm enough after 30 minutes to apply a second coat.
Which leads me to another good reason to use setting type compound versus pre-mixed.
If you use “45” you’ll typically be able to finish a drywall project in a small bathroom in one day!!!
The first coat will dry within 45-60 minutes which will allow you to sand it smooth and apply a second coat within 2 hours.
If you use pre-mixed products they take considerably longer to dry.
I’ve waited a full 24 hours and sometimes the pre-mixed compound is still too wet to sand.
Now, all of this depends on the ambient temperature and humidity.
But I’ve switched to setting-type joint compounds and have been super happy with the performance & time savings.
Even if you’re hiring a contractor it’s still a good idea to become familiar with all the different types of building materials.
This will allow you to make the best decisions for yourself & your family when it comes to preserving the air quality of moisture prone spaces in your house.
We like cement board but if you’re waterproofing a shower don’t forget to research KERDI-BOARD and Wedi. Both are fantastic backer boards.
If you’re doing a bathroom remodel and need help, join one of our online courses – they’ll make your bathroom renovation much easier!
Let me know if you have any questions and I’ll do my best to help.