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r/DIY on Reddit: Tiling shower... is a waterproof membrane necessary?
August 9, 2016 -
We gutted our bathroom and installed a steel tub. Our plan is to use 12x12 porcelain tiles from the tub to the ceiling. We already installed hardy board and are ready to proceed but we have gotten mixed advice.
In the old shower, we had some grout problems and water found its way through and damaged the floor and the first floor ceiling (underneath the tub). This time around, we don't want to cut any corners with waterproofing. We planned on using thinset and/or tape on all the hardy board joints, screws, etc, and then coating everything with a membrane such as Red Guard, Ardex 8+9, etc). However a contractor we know and a local tile store told us these waterproof membranes are totally unnecessary if we do things correctly. They said thinset itself is sufficient to waterproof anything.
I feel like I should trust this advice but I just can't help but think we will inevitably have a problem, even if it is years down the line, and I will regret not going with a membrane as an extra layer of protection.
Thoughts? Any disadvantages to overdoing the waterproofing?
Top answer 1 of 5
33
Finally something I can answer! I have worked in pool and medium-large bathtub construction and installation for the last 5 years, so I might be able to give a bit of insight. So, the answer to this one is that he is half right. Using a waterproof membrane is like wearing a condom, if you know how to pull out properly you don't need it, but if you try to get by without one and fuck up, you have 18 years of child support payments waiting for you. Similarly, there are definitely ways of water proofing without resorting to a membrane, but if this is your first time, its probably safer to use one. However, if you do decide to go without, make sure to both thinset AND tape vulnerable points, but make sure to also cross tape a few times to keep moisture from loosening the adhesive. That being said, beware of over-proofing the base if you go with the membrane option. If you are using a membrane with a DG or DG- rating, you should under no circumstances double proof, like you would with say a P-k rating or higher. This is because the porosity of the clay based polymers is variable among membranes (hence the DAR rating) and is also variable to an extent within production batches, which is why it's always recommended you do a copper-phosphorous drain test before applying. As long as you use the old "DG thin on me, R/P(i,k) lay it on thick" saying, you pretty much can't go wrong. Tl;dr either way could work, but a condom is better for virgins. EDIT: misspelled porosity, thanks u/198jazzy349
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It depends on what you are using for your tile board. If you use Durarock or another cementitious board, then you should use a waterproofing membrane. However, some boards, like Diamondback have a built in moisture barrier and don't need an additional membrane. Your best bet is to read the manufacturer's product data and do what they recommend. Source: I'm a commercial construction general contractor
Schluter
schluter.com › membranes › waterproofing (kerdi) › schluter®-kerdi
Schluter®-KERDI | Waterproofing (KERDI) | Schluter
Schluter®-KERDI is a pliable sheet-applied waterproofing membrane and vapor-retarder designed for the direct application of tile.
Videos
11:40
Foolproof Waterproofing for a Tile Shower | Liquid Membrane - YouTube
Waterproofing a Bath | This Old House
25:47
Which Tile Membrane Installs Faster and Easier? - YouTube
01:05:28
Waterproof Your Shower (Or Else) - YouTube
19:38
Which Liquid Membrane is BEST??? —Testing HydroBan vs. RedGard vs.
Amazon
amazon.com › Waterproof-Membrane-Flooring-Underlayment-Ceramics › dp › B08NDKTSHM
108 SQ FT Waterproofing Membrane for Bathroom Shower, 27.6mil, 3' 3" x 32.8FT Tile Flooring Underlayment Roll Under Ceramics, Natural Stone Tiles and LVT for Shower Wall, Bathroom Floors - Amazon.com
UCANVIN Waterproofing Membrane Band Roll, 30Mils Thick, 5Inch X 98.5Ft Tile Floor Underlayment Waterproofing Polyethylene Fabric Waterproof Membrane for Tiles, Shower Walls, Bathroom Floors
Mapei
mapei.com › home page › training › "tech talk" blog › detail
A Beginner’s Guide to Waterproofing Membrane and Shower Floor & Tile Installation with LVT | Mapei
A waterproofing sheet membrane such as the Mapeguard WP 200 is designed to be installed on the surface of the tile backer board and shower base, using either a thin-set mortar or self-adhesive “peel-and-stick” technology.
LATICRETE
laticrete.com › our-products › tile-and-stone-installation › waterproofing
Waterproofing Membrane Products | LATICRETE
Yes, if the waterproofing membrane is manufactured specifically to accept tile, stone or other adhered veneer. LATICRETE® waterproofing membranes are manufactured for such applications on a wide variety of applications over a multitude of substrates.
Remedial Membranes
remedialmembranes.com › home › shower waterproofing
Shower Waterproofing - Remedial Membranes
Most tiled shower leaks are due to movement. Our paint-on waterproofing membrane is flexible.
The Tile Shop
tileshop.com › shop › shower-waterproofing-products
Shower Waterproofing Products
The Pro-Shield tile waterproof membrane is the tile waterproofing product used to prep tile for exposure to liquids or provide...
AMES Research Laboratories
amesresearch.com › home › all products › shop all › blue max® tile & floor
Blue Max Tile & Floor | Waterproof Tile & Floors | AMES
Very happy with this product.
Blue Max Tile & Floor® is a versatile ... in both commercial and residential tile and stone applications. It completely waterproofs bathroom floors, walls, showers, shower pans, and tub surrounds, curing to form a flexible monolithic membrane with up to 1200% elongation... I made the change to Blue Max for bathroom tile installations, and I am so glad I did!
Schluter
schluter.com › tiled shower waterproofing systems
Tiled Shower Waterproofing Systems | Schluter
It begins with the installation of a mortar bed over the subfloor that is sloped to the weep holes in the drain. A waterproofing membrane, typically referred to as a pan liner, is subsequently placed over this "pre-slope" and clamped into the drain.
This Old House
thisoldhouse.com › home › how to use a membrane system to waterproof your shower
How to Use a Membrane System to Waterproof Your Shower - This Old House
A waterproof membrane system creates a barrier between the shower’s structure and the surface of your tiles.
Published July 8, 2025
The Home Depot
homedepot.com › flooring › flooring supplies › surface prep › underlayment
Tile - Waterproofing membrane - Underlayment - The Home Depot
Flooring Type:Tile · Flooring Material Features:Waterproofing membraneClear All · (4.5 / 133) Model# KERDI200/5M · See Low Price in Cart · Add to Cart · (3.8 / 100) Model# RGM254 · $2.02 · /sq. ft. ($109.00) Add to Cart · (5 / 1) Model# RFM108 · $1.80 · /sq.
Schluter
schluter.com › shower system › waterproofing
Waterproofing | Schluter
Schluter®-KERDI is a pliable sheet-applied waterproofing membrane and vapor-retarder designed for the direct application of tile.
Koffler Sales
kofflersales.com › category › tile-membrane-primers
Premium Tile Membrane and Primer for Tiling Installation
On sale now, 10% off regular price. Starting at $29.53 ... Seal pipes, mixing valves and other protruding elements with pre-cut seals constructed from Schluter KERDI waterproof membrane.
The Tile Shop
tileshop.com › shop › waterproofing-membranes
Waterproofing Membranes
Superior Pro-Shield Membrane - 3 ft. 3 in. x 33 ft. ... The Superior Pro-Shield Shower System contains all the pieces and accessories you need to fully waterproof and prepare a...
Contractors Direct
contractorsdirect.com › home › waterproofing membranes & uncoupling membranes
Waterproofing Membrane | Contractors Direct
Waterproofing is critical in areas like bathrooms and kitchens. Preventing water from seeping through the tiles and causing damage to the underlying structure. Contractors Direct offers a wide range of top-rated waterproof sheet and liquid membranes from trusted brands like Schluter, Laticrete, and Mapei.
Tile ProSource
tileprosource.com › collections › underlayments and membranes
Underlayments and Membranes
Decoupled, or separate, surfaces are created between the substrate and the tile by installing these membranes, which are usually composed of flexible materials like polyethylene or polypropylene. This prevents movement from damaging the tile. In places where tile installations are likely to be damp or exposed to water, like bathrooms, showers, or outdoor patios, waterproofing membranes are necessary.
Call 877-712-6773
Address 225 Transport Dr, 38506, Cookeville
Tile Club
tileclub.com › blogs › news › tile-shower-waterproofing-methods-to-prevent-moisture-damage
Tile Shower Waterproofing Methods to Prevent Moisture Damage
Liquid waterproofing membrane is exemplified by Redgard Waterproofing Membrane by Custom Building Products, although there are also a number of other brands out there. This is the easiest and cheapest option among the new waterproofing systems, which can be applied to any surfaces that come into contact with water or moisture. It can be used for both bathroom walls and floors, including horizontal areas exposed to moisture such as shower benches, shelving, half-walls, niches, and especially the shower floor.
Fine Homebuilding
finehomebuilding.com › tile a barrier-free bathroom: waterproof membrane
Tile a Barrier-Free Bathroom: Waterproof Membrane - Fine Homebuilding
The water-proof membrane that I am using here is called Kerdi and it is made by the Schluter Systems Company. It is almost paper thin and very easy to work with. It is applied with non- latex mortar.
Published July 9, 2021
Amazon
amazon.com › Waterproof-Membrane-Uncoupling-Waterproofing-Thickness › dp › B0D93Z6HX3
Seamaka Waterproof Membrane Shower Membrane, 5Inch X 100Ft 20Mils Thickness Waterproof Membrane for Shower for Tile Flooring PE Fabric Sauna Bathroom Walls Tile Underlayment O-097 - Amazon.com
Seamaka Waterproof Membrane Shower Membrane, 5Inch X 100Ft 20Mils Thickness Waterproof Membrane for Shower for Tile Flooring PE Fabric Sauna Bathroom Walls Tile Underlayment O-097 - Amazon.com
Amazon
amazon.com › Waterproofing-Membrane-bathroom-flooring-thickness › dp › B083LKCY3Y
SIMPLYHARDWARE Waterproofing Membrane for Bathroom, Shower and Tile Flooring | 3 Ft 3 inch x 33 Ft (1 Meter x 10 Meter) | 108 Square feet | 8 mil Thickness | Roll Package - Amazon.com
108 SQ FT Waterproofing Membrane for Bathroom Shower, 27.6mil, 3' 3" x 32.8FT Tile Flooring Underlayment Roll Under Ceramics, Natural Stone Tiles and LVT for Shower Wall, Bathroom Floors