DH's coworker is a professional tile installer and insists that no membrane is needed if grouted, sealed and caulked properly. He guided dh on doing our downstairs shower and we have had no issues. 6 years in. So in my limited opinion, it seems *okay*

However, this time around we are going with upgraded tile that I would be devastated to have to tear out. We are taking no chances. Using redgard over Duroc, over plaster.

The felt paper IS the water barrier. The pan liners IS the waterproofing. The two methods are fine, if each are installed correctly according to their particular methods. Ask for clarification about how he builds his shower pans. The mud pack preslope gets done before the shower liner goes down, not after on the flat to the subfloor shower liner.

I prefer the first if natural stone is to be used. It keeps it drier. The second lets it stay wet too long as it's porous right through the stone, mortar and durock, right to the felt paper.

Thanks for the replies. We are using standard porcelain tile. He did state the liner went in between. Also stated there is a double drain. I was just concerned since the liner only went up 6" and I knew felt paper was only a barrier and not waterproof.

Check over on john bridge tile forum for building showers. I believe I just read felt paper is not an acceptable practice anymore, but not sure as I wasn't researching that! They do know all the current best practices and standards in great detail and see a lot of failures and dumb things there.

No affiliation, it's just an exceptional site, informative and resourceful.

Thanks, snookums. I'll check it out.

I just looked briefly and it seems felt is still accepted practice. Could have just been one persons opinion the other day, in favor of newer products and methods. The membranes like redguard are the more expensive route. It all depends on your application specifics too. But if you have the floor built, be really careful who you hire! Do read around over there first and they can advise pros and cons on prospective plans.

Thanks snookums.

The second guy that builds the floor is a local. Live in a small community, and have known him for a long time. I actually had him to tile my floors in last home, but this is a first for us with a tile shower. I guess he is old school on the felt. He said he just doesn't trust the membrane because it is fairly new. I just needed some other opinions about it since I wasn't familiar with tile showers.

Check out Wedi Board.

Here is a link that might be useful: Wedi

Essentially, you have two options.

You can use the roofing felt on the studs...OR plastic vapor barrier. THEN you need to put in a preslope, cover THAT with a rubber liner (make sure to block the weepholes with pea gravel) Then, you install a final mud slope at a minimum of 1/4" slope per foot from the drain. THEN you can actually install your tile. (sigh)

I far prefer the SAM (Surface Applied Membrane.)

With this, you simply drywall the walls. Put in ONE "mudbed" and cover EVERYTHING with Schluter's "Kerdi" or Laticrete's "Hydroban" and tile everything. NO "Double Mudbeds," no paper or plastic on the studs...

Once the Kerdi is in...you can take a shower! The only thing the tile does is make it look pretty.

I do 'Em this way and give a lifetime warranty. What does that mean? I tell my clients, "Until you or I die...." LOL

Seriously, try Youtube for "Kerdi Showers," or their manufacturer, Schluter for videos on Kerdi Showers.

Best of Luck!

Thanks for all the replies. We have decided to go with the second tile guy. Price is important and after research it seems his method is standard among the membrane system.