Where can I buy the automatic in-line shut-off valve used in this video?

This comment was posted to reddit on Jun 24, 2017 at 1:13 am and was deleted within 12 hour(s) and 36 minutes.

Where can I buy the automatic in-line shut-off valve used in this video?

What is a waterproofing membrane?

A waterproofing membrane is installed when one is concerned about moisture getting into and affecting building materials in a given area.
It is commonly used for a shower. The membrane is applied not just below the shower pan, but behind the shower walls as well.
It is true that a properly installed shower should not need a membrane. While a waterproofing membrane may not be required by code, it is an inexpensive form of insurance to inhibit the possibility of water damage (especially if you are installing a shower yourself, and you are not a pro).
The membrane is typically applied directly over the cement board. The membrane is sometimes instead applied over greenboard (i.e., water‐resistant drywall).

Waterproofing membrane product options:

It seems that these are the two prevailing waterproofing membrane products used in the United States:

Kerdi (made by the company Schluter)
RedGard (made by the company Custom Building Products)

(There are also other products, such as Laticrete Hydro Ban and Ardex "8+9", that are very similar to RedGard. They are not as readily available, so I'm focusing on RedGard.)

Differences in application method:

A conspicuous difference between these two products is the fact that they are in different forms, and, therefore, are applied differently.

Kerdi membrane comes in a roll. It can be cut easily, like a sheet of felt. To attach the Kerdi membrane to the substrate, unmodified thinset mortar is used.

This is what a Kerdi installation might look like.

RedGard, on the other hand, is a pink liquid and comes in a bucket. It can be "painted" onto the substrate with a standard paint roller or sprayer. If you prefer, you can also use a trowel to apply RedGard. The end result is a red, film coating that basically "rubberizes" the area. The drying time is typically 1 to 1.5 hours, but, depending on the ambient conditions, RedGard can take as long as 12 hours to fully dry.

This is what a RedGard installation might look like.

So, as you can see, these are two different types of products, but they are competing products that accomplish the same thing.

Differences in cost:

Another consideration is the price difference between the two products.

One gallon of RedGard Waterproofing and Crack Prevention Membrane currently costs $49.97 at Home Depot. Each gallon offers 80 square feet of coverage. If one desires a waterproof membrane, RedGard recommends an application of two coats, so one gallon will offer a total of 40 square feet of coverage (per IAPMO standards). (Source: the third page of this PDF document.)

Note: Home Depot sells RedGard both online and in stores. Lowe's does not carry RedGard whatsoever.

A 54 square foot roll of Kerdi Waterproofing Tile Membrane currently costs $99.98 at Lowe's.

Note: While Kerdi products are sold on HomeDepot.com, no Home Depot stores near me carry any Kerdi products in store. However, Lowe's stores do stock Kerdi products.

(I'm guessing that manufacturer exclusivity deals might explain which products are sold at which big-box stores.)

Cost of each product per sq ft:

RedGard = $1.25 / sq ft
Kerdi = $1.85 / sq ft

In conclusion, Kerdi is significantly more expensive than RedGard.

Of course, cost will not be the only or most important factor in your decision necessarily, but it is worth mentioning.

Note: The above calculation is supposed to be a crude cost comparison. It does not take into account the cost of required tools (which should be relatively equal) and required accessory products (like seams). Also, this is the material cost and does not account for the time spent/saved with either method (i.e., the method's effect on the cost of labor).

A note on accessories:

There are no RedGard products, other than the membrane itself and the seam tape.

Schluter, on the other hand, has a whole line of Kerdi products. These products include a prefabbed niche, a prefabbed bench, a prefabbed curb, a sloped shower tray, and "KerdiBoard" (which is an enhanced type of cement board; the differences are explained here).

Initially, I had included this as a difference between the two products—that the Kerdi membrane is part of a broader and coordinated shower kit—but then I realized that this fact is not very relevant to the waterproofing membrane comparison.

Despite the fact that Kerdi membrane may be bundled with these prefabbed products in a "shower kit," and the fact that these products may share the "Kerdi" name, they do not have to be used in conjunction with a Kerdi membrane. For example, if you wanted to, you could use RedGard for your shower membrane, and also install a Kerdi shower niche (or any other shower niche made by a different company).

I understand that one may purchase these Kerdi accessories for convenience, but Schluter gives the impression that you have to buy into the Kerdi "system" and go "Kerdi all the way" in order to use them. I don't think that this is true.

In short, the desire to use a prefabbed Kerdi product does not inherently mean that you are then locked into using Kerdi membrane for the shower's waterproofing membrane. Schluter is simply a company that happens to also make prefabricated shower substrate components.

This post is only concerning the Kerdi waterproofing membrane, not the whole line of Kerdi-branded products.

Closing thoughts:

So, I've provided a brief primer on Kerdi vs. RedGard. I've never applied or tested either product before, so all of the above research is general information that I've found online.

I am hoping that someone with experience using both products can share the practical differences and nuances.

If there is another common waterproofing membrane product that I've omitted, feel free to throw that into the mix as well.