Bathroom proposal, what to ask about waterproofing?

User

7 years ago

last modified: 7 years ago

Hello, in the proposal from a GC, this is what he says about the shower area:

Install concrete backer board to shower walls and ceiling. Seal backer
board.

Install new shower pan.

Install tile to shower floor, walls, and ceiling.

Install glass shower enclosure with door.

It's not a steam shower, but it is going to be closed up with a transom window above the door. I don't know what questions to ask him or what additional information I need regarding waterproofing. There will be 2 niches. I have read/heard that waterproofing is harder for niches, so I'd want to ask him about that, as well as the waterproofing procedure for the whole shower. If I just ask "how will you waterproof?" he can say anything and I won't know the difference between a good answer and a bad one. I'll be able to see the progress each day bc I work from home, so I'd be able to verify that the steps were done, if I know what the steps are supposed to be.

Also, we want to slope the ceiling because of the steam build-up when the transom is closed. He didn't seem to think this was needed and the tile person didn't seem to have anything to say about that. Wouldn't that need to be done at the time of framing the shower? If someone could explain that to me I'd really appreciate it.

Thanks so much.

Featured Answer

MongoCT

7 years ago

Waterproofing is typically one of two ways when using cement board:

1) Plastic sheeting: 6-mil poly sheeting stapled to the studs with the bottom edge of the poly lapped over the face of the pan membrane.

2) A topical or surface applied membrane: The cement board is fastened to the studs and the niches inserted in their holes, then waterproofing is applied to the cement board and onto the niches as needed. The waterproofing can be a liquid-type of membrane, common ones are RedGard and Hydroban Liquid, or it can be a sheet membrane, common ones are Kerdi and Hydroban sheet.

There are other versions of each of these types of membrane from several different manufacturers, both sheet and liquid.

If using a liquid membrane, the manufacturer sometimes requires that the seams and corners of the cement board be treated in some way, sometimes with a strip of fabric reinforcement. The fabric allows the liquid membrane to easily bridge any gap at those seams. Sheet membranes usually don't require seam treatment as the sheet itself acts as the bridge.

For your shower pan, if you are getting a vinyl liner (CPE or CPVC, a common one is made by Oatey) on the shower floor, confirm that the liner/membrane itself will be sloped. IT IS A CODE REQUIREMENT THAT THE LINER BE SLOPED. Sorry for cyber-yelling.

Quite a few of the problems on this forum are from installers placing the liner flat on the floor, placing a sloped layer of deck mud on top of the flat liner, then tiling on that mud.

Briefly, the proper way is to install a sloped layer of mud (called a preslope) on the subfloor, then the liner goes on top of the sloped mud. Then another layer of mud is placed on top of the liner and the tile goes on that second layer of mud.

If you ask for the specific brand and type of waterproofing that will be used, you can usually find the manufacturer's installation instructions online. Then come back and ask away if you have further questions.

Good on your for asking. Good luck!

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Comments (17)

User
Original Author
7 years ago
Originally we thought we wanted a steam shower, but after trying some steam shower in hotels and at DS's house, we realized that we like it when it gets steamy in there from the hot water, but we don't actually like the steam being generated and pumped into the shower. I want there to be a build-up of steam because I don't like the cold air coming in from the top in the winter. So if we close it up, there will be a gradual build-up of steam without the pumping in of steam. It wasn't really a cost issue, but it just didn't seem like a good thing to spend money on if we didn't love it.

My DS loves hers and couldn't believe anyone would forgo the steam unit, but somehow it made me feel like I was choking.

So thus I want the glass to go to the ceiling and we will have a transom window above the door and a vent nearby in the ceiling.

Mostly I'm worried about the caliber of the waterproofing which would apply no matter if we were taking the glass to the ceiling or not. If there are any additional steps that must be taken because of the steam I need to know that too.
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User
Original Author
7 years ago
MongoCT,

You can cyber-yell all you want. I'm here to learn. Learning more might keep me from real-life-yelling later.
jellytoast
7 years ago
Ask him to provide details on the bid. Personally, I'd never agree to anything so vague.
User thanked jellytoast
MongoCT
7 years ago
You can also include in the contract that everything be done to TCNA standards.
User thanked MongoCT
User
Original Author
7 years ago
I went to the TCNA website and there are so many pages and links. What should I be looking for?
User
Original Author
7 years ago
jellytoast,

What details should I ask for? The type and brand of materials to be used? The waterproofing methodology? If I just ask "give me details" I don't know if that is asking the right question.
Katrina Tate
7 years ago
Our plans call for laticrete waterproofing 9235. They started yesterday. It's a blue liquid and turns black. They also used fabric in between layers.
User thanked Katrina Tate
User
Original Author
7 years ago
Can I ask this:

If there is someone on this forum who has an old contract that spelled things out clearly and then the job was done well. Could you share that language with me? I'd like to see what level of detail I should be shooting for.
caligirl5
7 years ago
I have a very similar question and hope this isn't hijacking the thread. I asked my contractor about waterproofing for my shower tub combo, and he told me hardiebacker then seal the seams. I understand the hardiebacker alone isn't waterproof and am not sure what makes sense to get it done right.

1) Ask him to do use one of the methods MongoCT suggests above.

2) Would any other waterproofing method (not involving the hardiebacker) be better to suggest? i.e. easier to use effectively

3) Job hasn't started, nothing signed, no $ paid. Should I find a different contractor?

Thanks in advance!
User thanked caligirl5
PRO
Avanti Tile & Stone / Stonetech
7 years ago
Just cover the walls with plain old white drywall and apply Kerdi over it, seaming it down and over a mud bed floor with a Schluter drain. Easy, quick, reasonably priced and waterproof. 'Nuff said.
User thanked Avanti Tile & Stone / Stonetech
PRO
Joseph Corlett, LLC
7 years ago
I've done one Kerdi and I'm a fan. It's pretty much idiot proof. And water proof.
User thanked Joseph Corlett, LLC
PRO
Mint tile Minneapolis
7 years ago
last modified: 7 years ago
some valid advice and some great info from others... Its Just that the number 1 question you should ask has not been touched upon and it is called a "flood test" preferably an permitted/inspected flood test one in which you verify every drop of water quickly runs down to the drain and no pooling is evident.

many tile pros skip this step still today... and want easy and quick so they can move on to the next earning..

This along with the proper wording in youre contract will help you eliminate hiring the wrong tile professional.
User thanked Mint tile Minneapolis
User
Original Author
7 years ago
Never thought of the flood test, thanks!
PRO
Creative Tile Eastern CT
7 years ago
You should be able to take a shower without any tile installed and have it be completely waterproof. If an installer can't agree with that get another installer.
PRO
Joseph Corlett, LLC
7 years ago
last modified: 7 years ago
"You should be able to take a shower without any tile installed and have it be completely waterproof. If an installer can't agree with that get another installer."

The one and only Kerdi job I've done was completed just before my 10-day Yellowstone vacation which the customer knew about in advance. She showered in a Kerdi with no tile for nearly two weeks. Quite happy about it as a matter of fact.

Bathroom proposal, what to ask about waterproofing?

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