I feel that topical membranes are the best way to control moisture. Of your three choices, that puts you in the "Wedi" camp.

Since you liked the "membrane" guy best, and he's also a tiler, why don't you see if you can cut a deal? See if he's willing to try a Laticrete flanged drain with Hydroban as the topical waterproofing membrane?

All he'd have to do differently is to use a flanged drain instead of a clamping drain. Easy.

And he'd only have to do a single sloped mudbed for Hydroban versus doing two layers of mud with a CPE membrane. Double easy.

Hang the cement board on the walls. Set the drain. Do the sloped deck mud floor. Then Hydroban everything.

To me, Hydroban is easier than Wedi, less expensive than Wedi, and more customizable than Wedi.

Thanks Mongoct -

The membrane guy (who I liked a lot) speaks english as his second language... and he does a fairly good job of it and together with my terrible spanish, I think we're ok. However, because of this, I would hate to try to describe something different I want him to use, and explain it only halfway. I think if we go with him, we may want to just let him do his thing on the technique level, while I communicate my design issues.

If you were ranking them, you would put Wedi first, then the membrane guy then the hot mop?

I liked the Wedi guy too - just felt he was a better generalist rather than tile guy, he seemed to know his stull and he listened to what we wanted and offered suggestions, That said, also as a result of the water damage we need some sheet rock and molding work done, and his estimate still hasn't come in for that, just the bathroom.

The Wedi is absolutely the latest and best technology. We us another brand, but it's essentially the same process. Hot moping? I didn't think anyone did that any more.

Wedi is a fine product (except for steam showers), but it does have to be detailed correctly. It'll be the most expensive of the three.

CPE or CPVC membranes are more common, and much less expensive than Wedi. You mentioned cost being an issue, but you can feel safe with a CPE membrane as long as everything is installed properly.

Just make sure he does a mud preslope, then puts the membrane on the sloped mud, then covers the membrane with another layer of mud. Too many people put the membrane flat on the floor then put sloped mud on top of that. The membrane itself needs to be sloped.

Here's a pretty good primer on the steps for a CPE membrane shower.

Note that in that installation, there are no fasteners at the bottom of the cement board on the walls. Also no fasteners were used on the inside face or on the top of the curb. You don't want holes in the membrane in those spots.

Hot mopping is pretty much a west coast thing, it's not accepted here in New England. I don't even know if they slope the hot mop or not.

So, if you want a topical membrane and as a result the better method if moisture control, go with Wedi.

If Wedi will blow your budget, feel comfortable going with a CPE membrane. Just make sure the membrane itself gets sloped.

Hot mopping? I can't advise on it. It works. But I'm just not that familiar.

Thanks so much! I really appreciate your expert perspective.