On paper, installing a backer board over a tub flange may seem easy. But when you get to work, you realize how complex this task is.
You even get more confused when you read through home improvement forums because every DIY enthusiast has their approach.
To make your work easier, I have decided to share a comprehensive guide on how to install a backer board over a tub flange.
This is the method that is recommended by expert contractors and you’ll never run into any problems in the future.
Should Backer Board Go Over the Tub Flange or Behind It?
Let’s start with addressing the confusion about where backer boards should be installed when it comes to tub flanges.
Some say the backer board should go behind the tub flange. But the best method is to install it over the tub flange.
The purpose of a tub lip is to prevent water from going behind the tub. Therefore, if you install the backer board behind it, you wouldn’t be helping the flange do its job.
However, when the backer board is installed over the flange, there is minimal chance of water splashing behind the tub.
In all professional tub installation jobs, the tub is often installed first and then the backer board goes second.
The reason behind this approach is to ensure that the backer board is installed over the flange just at the top of the tub lip. Do you now understand why the backer board has to go over the tub flange?
How to Install Backer Board Over Tub Flange?
Once you understand why the backer board should go over the tub flange, the following steps be easy.
Step 1: Install the Tub into the Desired Area
It can be tempting to start with the backer board first, but I’ve already explained the benefits of installing the tub before the backer board.
So, depending on the type of tub, install it perfectly in your shower while adhering to manufacturer instructions.
Step 2: Wrap a Moisture Barrier Behind the Tub (Around the Flange)
Backer boards like cement boards are very porous. To ensure maximum waterproofing of your setup, please wrap a moisture barrier behind the tub.
This is the area around the flange. You can use a moisture barrier of your choice as long as it’s effective.
Step 3: Cut and Fit the Backer Board
When cutting the backer board, make sure that it reaches above the lip of the tub. The gap should be as small as possible. Bigger gaps are a recipe for failure.
If you fit the backer board several inches above the flange, you’ll have trouble installing tiles around the tub.
Also, any transition material placed there won’t be structurally strong. Ensure that the backer board is firmly screwed into the frame.
Step 4: Apply Sealant in the Space Between the Backer Board and Tub Lip
Next, you should apply some silicone sealant between the backer board and the tub lip. This gap must be thoroughly sealed so that water doesn’t get past the backer board and flange.
And from there, you can tile over the backer board and never have to worry about water damage for the rest of your stay in that home.
Please be very generous with the sealant as that ensures minimal passage for water or moisture.
What Type of Backer Board Should You Use Over Tub Flange?
There is one important detail that you need to keep in mind and that’s the best type of backer board to use over a tub flange. The tub is often exposed to a lot of water and moisture.
Therefore, the best type of backer board for tub flanges is the cement board. Cement board, though porous, it is water resistant and very durable.
It can be soaked with water every day and it will not deteriorate. As long as you’ve got a moisture barrier behind it, your bathroom will be protected from water damage.
The other reason why you use cement backer board over the tub flange is because it’s a suitable tile substrate. Tiles thrive well on cement board.
Other types of backer boards like gypsum board aren’t ideal for use around tub flanges because they are not moisture resistant.
Also, they are not as sturdy as cement boards. A slight exposure to impact can cause a huge dent in these other types of backer boards.
Why Use Backer Board Over a Tub Flange?
First of all, a backer board is required by most building codes as the preferred wall material in high moisture areas like showers and bathrooms.
A backer board also offers a stable surface for the installation of tiles around your tub flange. Without a backer board, there would be nothing to adhere tiles to.
Also, when paired up with a moisture barrier, backer boards prevent moisture from penetrating the area behind the tub flange and damaging other materials like wall frames and studs.
And most importantly, a backer board enhances the overall aesthetics of your bathtub.
Common Mistakes to Avoid When Installing Backer Board Over Tub Flange
If you follow my guide, then I guarantee that everything will work perfectly.
However, I always encourage my readers to familiarize themselves with the common mistakes people make when installing a backer board over a tub flange. This helps you avoid such mistakes and increases the success rate of your project.
So, check out some of these mistakes you need to be mindful of;
• Leaving a big gap between the backer board and tub flange – Doing so leads to three main problems. First, you’ll have a hard time covering that gap. It’ll also be challenging to create a solid surface to lay tile. And finally, prepare to deal with moisture damage.
• Installing the backer board behind the tub flange – Unless you’re a skilled tiler/plumber, if you do this, it will be impossible to prevent water from going behind the tub. The best approach is to follow my instructions and install the backer board over the tub flange.
• Not wrapping a moisture-resistant barrier behind the backer board – What most people forget is that cement board is water-resistant but not waterproof. Some moisture will pass through and if there is no barrier, it will spread to the frame inside your walls.
• Forgetting to use sealant – All gaps, spaces, and seams must be sealed using a quality silicone sealant. That’s the only way you can be assured of waterproof seams.
• Tiling immediately after applying sealant – Rushing any part of the above process is catastrophic and can lead to expensive failures. Take your time to ensure everything dries on time before proceeding. Most sealants cure in less than an hour.
Should You Hire a Professional to Install Backer Board Over a Tub Flange?
If you hadn’t stumbled across this review, I would advise you to hire an expert contractor to install a backer board over a tub flange. However, I’ve provided you with everything you need to know in this review.
So, I believe that you can pull off this project by yourself. hiring a contractor means that you’ll have to part with more money that could have been channeled to other home renovation projects.
Just follow my steps and make sure you avoid the common mistakes discussed earlier.