A DIY guide to waterproofing your bathroom

We are currently in the middle of renovating our master bathroom due to a water leak that caused mold growth and wood rot to the walls and floor. That’s not a pleasant thing to happen by any means, but we have learned a lot from the experience, and I want to share some of those tips here. Basically, I want to walk you through the process, from the moment you realize there is a problem, to the moment you are standing in your brand new bathroom.

I considered making this a tutorial for building a shower, but let’s be honest, there plenty of those online. I’ll link some of the ones we found most helpful. I will also link the supplies we used, tell you why we chose what we did, give some recommendations, and help you sort through the countless details that go into renovating a bathroom. This will be long, but I’ve divided everything up so you can easily find what you need.

Here’s what we will cover:

1. How to know there’s a problem and what is causing it
2. Fixing the problem
3. Planning your new space
4. Building a shower kit
5. Waterproofing considerations for the rest of the bathroom

While this post is unsponsored, it does contain affiliate links. You can check out all the details on those here: 

This post is part of the One Room Challenge, in which we are remodeling this bathroom in the space of 6 weeks time. You’ve found your way to week 2. Be sure to follow along for more!

1. How to know there’s a problem and what is causing it

Every bathroom, and every problem that can develop in a bathroom, is a little different. But there are common red flags.

Smell:

Maybe it’s your Uncle Joe that came for Thanksgiving dinner and overdid it on the cranberries. But if it lingers longer than that, if you are noticing that no matter what you do, something smells off…you are probably right. It’s kind of a gross indicator, but whether it’s mold grow, water soaking into wood, or a failing toilet seal, it will smell.

Bulging:

Sheet rock or baseboard will swell and bulge if infiltrated with water. It will also likely discolor and be soft when pushed on. All are signs of trouble.

Excessive mold build up in the tub and shower:

If you find that no matter how much you clean mold keeps coming back in the seams that form your tub and shower, the likely culprit is mold growing behind the walls.

Visual:

If you have access to the space under the suspected plumbing area, you can check for indicators such as those listed above, dark spots where water is soaking in, and most obviously, leaking. Turn on the water and watch the spot for active leaks.

So what happened with yours?

Well, it’s kind of embarrassing, but we had three problems. There was a problem behind the wall with the shower head plumbing. The tub that was installed 10 years ago apparently wasn’t appropriate for the space as it lacked a lip around the back edge, and the flange to our toilet sat just below the tile so that it wasn’t sealed correctly. Over time all three failed.

[For the record: None of it was our work.]

2. Fixing the problem

Look, I run a DIY blog. And I love demo day as much as or more than the next person. But the thing to do here is to put down the hammer and check your insurance coverage. Be aware that not all plans cover mold and water damage. My biggest takeaway from this whole experience was that it is always worth paying for a plan that covers those things.

Because you will ask, we are covered through USAA. I do not know how plans compare. But I can tell you that our remediation bill was $7,376.06. That amount also accounted for the asbestos removal we ended up needing to have done as well. It is also just about what we estimate our costs will be to rebuild this bathroom with us doing all of the work. So that’s a $14K bathroom renovation…and that’s a lot of money.

Check your insurance.

Working with Insurance to Remediate the Damages

*This information may be useful to you if you need to work with an insurance company.*

Unless you have done this before, you may feel as lost as we did. I don’t know how processes compare, but what we did was to reach out to an approved restoration company. We called a couple, and the one we went with came out, assessed the damage, and sent us and our insurance company a full bid. Part of the reason we went with them was because they were familiar with our insurance provider and knew the process themselves. That’s my next tip for you, because it helped a lot.

The restoration company was also able to report the value of the materials removed to our insurance.

Then, over the course of the next few weeks, they came out to our house repeatedly to set up barriers, demo the bathroom, remove materials from our home, clean the air, and make sure everything was dry. After completion of the work the insurance company cut us a check, which we then used to pay the restoration company.

We next had a couple companies give us estimates to complete the work on the bathroom, as well as the affected bedroom. Those bids served as a baseline for insurance to know what it would cost to rebuild the bathroom as it was. From there we took over and did the work ourselves. They set how much they would give us, gave us half in advance, and will pay the other half upon completion. In this case, a report of all expenses with receipts is enough for their evaluation.

Again, the process probably looks different for each company, but that’s how it worked for us.

A final note about demo

If you are going to demo your own space be aware of any dangerous materials, such as lead paint or asbestos.

Here is what we keep in our demo tool kit:

Reciprocating saw with extra blades: Our number one demo tool. Also, be aware that you may need to remove your old tub/shower combo by cutting it apart with this.
Circular saw: For when you need long, straight cuts. Such as removing portions of flooring, etc.
Hammers: We personally find it helpful to have both claw and framing hammers on hand, the main difference being the curved versus straight claw. Both are useful.
Drill with multiple bit head types
Pry bars in multiple sizes
Utility knife
Tape measure: For “will this fit through the door?” moments
Contractor garbage bags
Respirator masks: Protect those lungs!
Gloves
Electrical tester: So you can make sure all exposed wires are dead
5 gallon bucket: Just…we always need one
Bandages: Somehow, you always end up needing one

I know, there’s no sledgehammer on the list. Despite what HGTV would have you believe, we rarely need one. (Though it doesn’t hurt to have one…and maybe has therapeutic benefits.) And, for the love all of all that is holy, don’t hit old cabinets with a sledgehammer – just unscrew them from the wall!

3. Planning your new space

If you are planning to change the layout of your bathroom there are some things to know.

Building Codes

First, check online for code requirements before moving forward on anything. For example, code for toilet areas is that there needs to be 30” side to side for a toilet space. That was important to us, because there was only so much room in this small bathroom, and we wanted to maximize the shower. The walk in shower would only work if we bumped the wall out a little to insure there was 30” left for the toilet.

The answers to most questions about code can be found online, or by talking to an expert in your area. Another resource is to check your local home improvement store, where they may have a department that will sit down with you and walk through planning the space. Cabinet departments, for example, need to know what the space looks like, and will walk through a design with you if you are considering purchasing something there.

Plumbing

It is always cheaper to leave the plumbing where it is at. Of course, we moved every last piece of ours because that’s how life goes sometime. Advice on plumbing is beyond the scope of what I’m going to do here, so I will recommend that you consult with a professional if you plan to change the layout that extensively.

Layout

The final piece of advice I will give is to layout your new space with painters tape on the floor once you have everything cleared out. Even with 3d rendering programs we consider this an essential part of the process. Mark out the outline of your vanity, your shower and/or tub, toilet, and anything else in the space. Walk through the space. Go through your morning or evening routines there. Go through it with your spouse. It’s better to find out now that the space is too tight for two people, than to be annoyed with each other in your newly renovated bathroom.

Insulation

While insulating interior walls is not a requirement, we wanted to dampen the sound of the shower, which is located on the same wall as our main hallway. I found a dearth of information about this online, and ultimately we decided it was probably worth it to do so. We used Rockwool insulation because it is water resistant, doesn’t contain fiberglass, and it is sound absorbing.

My six year old installing the Rockwool insulation

To be honest, I didn’t expect much from that last part, but oh-my-gosh, it works. We are still in the construction phase, so I haven’t tested it with the shower on (because it’s not finished yet). Even without a door on that bathroom yet sound is reduced big time. If one of us is working in there the other person cannot just call to them from another room. It also helps that we can work on the bathroom after the kids go to bed. The insulation has so far outperformed what I thought it would do that I wish it were in every wall. And no, this isn’t sponsored. Though when I build my shop we should talk, Rockwool people.

4. Building a shower kit

We chose to go with a shower kit for this bathroom, so that’s the option that I am going to speak to here. What is nice about a kit is that it can be customized precisely to your space. They can also look higher end than  prefabricated showers.

Working with a Schluter Shower Kit

Because of the leaks and issues that led to our remodel, we knew this is where we wanted to put our focus, and our money. When we determined the budget it was shower first, then everything else. Contractor after contractor told us they recommended Schluter. We did our research and agreed that a Schluter kit was the way to go for us. There are others, but frankly, I know nothing about them. I will also make it very clear here that this is not sponsored, meaning I can give you the good, the bad, the pros, the cons, and my absolutely truthful opinion about working with the Schluter kits.

Long story short, I love them and will use them when we build a third bathroom in this house sometime in the hopefully near-ish future.

Determine the dimensions of your shower

This can be overwhelming. Decide the size of your shower based on your space and by laying things out on the floor with painters tape. Our bathroom is on the smaller side, being just over 8×8’ square, but we really didn’t want to skimp on the shower. This is where you will decide on the size of your shower down to the inch.

*Determine the size of your shower based on the available kits, but understand that the tray can be cut down, so if it’s close, but just under the kit size, you will be able to make it work. Just don’t go the other way, as in close, but a little bigger, because your tray will not work for that.

We cut our tray down to allow space for a bench. The curb is also adjustable. If we had planned better we would have cut it to the width and height of our tile, but unfortunately we realized that afterward. Know that these components can be adjusted!

Figure out which components you need

The Schluter kits include a preformed shower tray, waterproofing membrane, valve seals, corners, drain, and preformed curb. These are the basics of what you will need for your shower, but there are other parts, and that can be confusing. In an attempt to help I’ve diagrammed what our shower needed and linked all of the parts. Every shower is different, of course, but it should be a good reference point to understand the materials available. I think this is probably the most valuable part of what I can offer you here, and hopefully it will help you wrap your head around the various components.

Components:

Shower kit – includes preformed tray, curb, valves, corners, membrane, banding, and bench. The kits come in difference sizes.

Kerdi membrane – because we extended the shower with the bench, and because we wrapped the membrane around to the front of the two walls we chose to order a second roll of membrane

Kerdi Banding – The banding is slightly thinner than the membrane, so rather than cut pieces off the membrane we ordered another roll.

Preformed inside and outside corners – I picked up more of these to make sure we got every corner around that bench and the rest of the shower.

Kerdi Shower Niche – ours measures 12 x 28″. 

Kerdi Shower bench

Schluter Edge Profiles – To be clear, I did not order these from Amazon. You are better off if you can find them locally, as we did. The link is to the profiles we used, except they were the 5/15″ profiles to match our tile thickness.

Ditra XL Underlayment – The XL is 5/16″ thick, allowing it to replace cement board. 

Schluter All Set Mortar – This is what I wish we could have used, and I have since found locally. All Set saves you the process of having to use modified mortar in some areas and unmodified in others. But if you have to order it, give yourself plenty of lead time. 

If there is anything I wish was different about working with a Schluter kit, it is that it can be a bit overwhelming to determine which components to use. My ideal would be a program where you could input the layout of your shower and it would tell you what you need. Because the components work together so well you will most likely find that you want to use a number of Schluter parts.

If you have any questions, call the Schluter help number. (888-472-4588)  They are extremely helpful, friendly, and informed about all of their products. 

Shower installation helps:

Because I am trying to cram so much information into this post I am not going to walk through the installation process. We found the following videos to be a lot of help:

Great overview:

 More detailed instruction:

A more messy real world look at the kit installation.

Shopping for components:

My final word on this is that you should check around for the best pricing. A few components came from Home Depot, most from Amazon, and a little tile store in our area had the rest. So call any local stores that carry Schluter components and ask what they carry.

5. Waterproofing considerations for the rest of the bathroom

In the process of researching we learned that it was possible to integrate the Schluter Ditra floor membrane with the shower waterproofing in a way that would help make the entire bathroom resistant to water. We used Ditra XL on the floor in place of cement board (which lacks flexibility and is the cause of troubles in some areas). Next, we ran Schluter Kerdi membrane strips along the seams in the Ditra membrane. We also ran the banding and along all of the walls where they meet the floor.

Note:

Understand that tile and grout are not a waterproofing barrier. You need to insure that what is behind them will protect your walls and your floor.

Conclusion 

All of the things we discussed here happen before the bathroom is put together cosmetically. You won’t see them, and if done properly hopefully you will never see them again. Taking the time to insure that your bathroom is properly sealed and waterproofed will give you the peace of mind that you won’t have to rip into the walls again. And that is just one more reason to smile as you soak in the tub and enjoy that new space.

Good luck with your bathroom, and happy building!