waterproof membrane

[Cooler]

I'm planning on putting in a new shower in the master bathroom.  The old shower measures 30" x 30" and feels too small.  

I am planning on using a 30" x 60" porcelain over cast iron shower base (Kohler), which should remain waterproof for my lifetime.

It is the walls I want to get right. 

I am planning on using a Schluter/Kerdi waterproof membrane on the walls.  If I do that, do I use cement board for the backer or can I use green board sheet rock?

My main objection to cement board is the difficulty cutting it.

[DRAHandyman]

Per the Schluter/Kerdi Shower Book they recommend drywall.

Although drywall is the recommended backing for the Kerdi membrane, other backers can
be used. These include cement backer boards, approved foam boards, other varieties of gypsum
boards and concrete substrates

This is what I have used.  No problems at all.  Don't forget to install any blocking in areas  that you might need to attach grab rails etc, before you install the drywall.

[Lynden]

Per the Schluter/Kerdi Shower Book they recommend drywall.

Although drywall is the recommended backing for the Kerdi membrane, other backers can
be used. These include cement backer boards, approved foam boards, other varieties of gypsum
boards and concrete substrates

This is what I have used.  No problems at all. 

Which drywall is the best type to use -- regular drywall, green board, blue board or purple board?

https://www.thebalance.com/types-of-drywall-845079

[Cooler]

Which drywall is the best type to use -- regular drywall, green board, blue board or purple board?

https://www.thebalance.com/types-of-drywall-845079

For me the answer is easy.  I only need three or four sheets.  The only thing that is available like that is either regular drywall (in a variety of thicknesses) or green board.

I will use the green board.

[DRAHandyman]

I forgot to add, this is  a very cheap book to download and gives a lot of excellent tips.

http://www.tileyourworld.com/catalog/pro...aec1cb2ea2

[Cooler]

I forgot to add, this is  a very cheap book to download and gives a lot of excellent tips.

http://www.tileyourworld.com/catalog/pro...aec1cb2ea2

Thanks for the information.

Do you have any idea why cast iron shower bases are not  popular in the USA?  They seem very popular in Australia and New Zealand.  In any cases when I shopped for them I got more hits from those countries than from the USA.  

I understand that it is not as decorative as a tile base, but it is way nicer than the acrylic bases that most are offering.  It does weigh 220 pounds but that does not seem like enough to require any special support.  (In any case my house is built on 3" x 8" joists, and the code calls for 2" x 8" so I am not worried about the extra weight).

[Robert Adams]

Thanks for the information.

Do you have any idea why cast iron shower bases are not  popular in the USA?  They seem very popular in Australia and New Zealand.  In any cases when I shopped for them I got more hits from those countries than from the USA.  

I understand that it is not as decorative as a tile base, but it is way nicer than the acrylic bases that most are offering.  It does weigh 220 pounds but that does not seem like enough to require any special support.  (In any case my house is built on 3" x 8" joists, and the code calls for 2" x 8" so I am not worried about the extra weight).

           Because of cost. I aaways prefer any one piece shower base over a old style mud and tiled base. They just don't leak. But the cast iron is nicer as its more durable than the plastic. The color layer on the plastic ones does wear over time, even the good ones. 
           There are also cultured marble bases which are basically epoxy and stone dust. It's my favorite material for a long lasting enclosure but all the pieces are custom. 

        You can also get shower bases that are like a fiberglass that can be tiled over. They are difficult to find but they work well. 

           As for the original question, yeah just drywall it. I like their products but it isn't the end all and be all of solutions they just spend massive amounts on marketing hence the high product prices. The same can be accomplished with regard(or other brands) for a fraction of the cost and in less time and just as effective in the end. Ue epoxy grout and you can just put the tile on the drywall. Anything extra is insurance. But I hate using epoxy grout and it's around $70 a gallon.

[Cooler]

My  1953 era show pan is made from a single  piece of terrazzo.  It looks nice and it does not leak.  But it is very, very small at 30" x 30".

Grainger shows terrazzo shower pans but at 450 pounds they are quite heavy (more than 50% heavier than cast iron.   And about the same price, though Grainger has never been known for their low prices.

https://www.grainger.com/product/19RU52?...adType^PLA

I've also seen some stainless steel pans, but they are used with a teak slat raised floor.  I imagine the stainless steel would be very slippery and might pop and buckle under weight.

[Roly]

If this is to be inspected check to see if drywall, including green board is permitted in shower. I know kerdi will seal very good if installed correctly but it depends on inspector. If you don't like cement board you might look at something like DensShield. A small leak in the kerdi system will be a problem with drywall. Roly

[Cooler]

If this is to be inspected check to see if drywall, including green board is permitted in shower.    I know kerdi will seal very good if installed correctly but it depends on inspector.   If you don't like cement board you might look at something like DensShield.      A small leak in the kerdi system will be a problem with drywall.    Roly

There is not going to be any inspector.  I am going to do the work myself.  I just want to do it right.

The house, built in 1953 features (annoyingly) all plaster walls.  There is metal lathe and it kills WIFI reception in the house, it is a pain to mount anything on it, and remodeling is made tiresome.

There is probably plaster beneath the existing tile, but having observed concrete in some of the walls, it could be concrete too.

I may use cement board anyway.  I have not decided.