i do not think greenboard is recommended for shower walls anymore and how does your contractor intend to waterproof the niches? I think there are many red flags here. I am about to have my new shower that was done with the right materials, durock, Kerdi, preslope etc redone for somewhere an error occurred and my grout never dries. If it were done the way yours is being done my rooms below and beside the shower would also need to be redone. Thank goodness mine was installed with the waterproof membrane. Good luck.

pretty tile by the way!

You need waterproofing!

I'm not a fan of greenboard. It is no longer "code" in a wet area. Assuming you have poly or tarpaper put up on the studs BEFORE the greenboard, I guess it's OK.

Were it me, I'd eliminate the GB and use regular drywall covered with Kerdi.

Greenboard is not allowed in wet areas. At all. Must be cement board. With either felt or poly behind it, or waterproofing over it. I don't care how many years he has been building them wrong. He's still wrong.

Thanks all. I'll be calling him in the morning.

I just completed a bundle of Internet surfing.

From what I can see -- I am going to have to have him replace the greenboard in the tub shower with the proper materials. Apparently in Massachusetts (in the overall state, not a metropolitan area or such), it does not yet appear to be embedded in code, but STRONGLY suggested. (This is the Internet -- i may have missed the appropriate citation....)

However, code or not where I am building, I want the best house i can build. Yes this will cost more and set back an already depressive timeline, but it needs to be done.

The GC's son-in-law (who is the tiler) doesn't work on site except on Saturdays or Sundays, so I doubt there is much more up than already depicted. I'll be e-mailing the online documents I've been able to scare up, to my GC today.

One thing I didn't get full info on -- would a membrane be desirable/necessary with the correct board? (I am planning on asking for durock, since that seems most frequently mentioned.)

I'll also make sure those inserts are fully waterproofed.

No tile is up in the master shower at all. One small thankfulness.... (although the green board is already there). There are to be no inserts for shampoo etc in the master as that is being built to to ADA wheelchair access drive in. But I do want those in the guest -- done right, of course.)

Thank you all, for your ongoing help.

MongoCT -- the insert locations were decided on later in the building process. I'm not going to fault him for that. Although I'll watch to make sure they are protected appropriately.

"Apparently in Massachusetts...it does not yet appear to be embedded in code, but
STRONGLY suggested. (This is the Internet -- i may have missed the
appropriate citation....)"

Check R702.4.2, it tells you what may be used as a tile backer in wet areas like showers. Moisture resistant gypsum board (green board) is not one of the boards listed.

In general, what is approved are cement boards like Durock or Wonderboard, fiber-cement boards like Hardie, and glass-mat boards like DensShield.

"One thing I didn't get full info on -- would a membrane be
desirable/necessary with the correct board? (I am planning on asking for
durock, since that seems most frequently mentioned.)"

I think you get the best waterproofing with a surface applied membrane. Durock is a great choice for the backer board. If you want a SAM, you can use a liquid membrane; Hydroban liquid and RedGard are two of the more commonly available ones. Or sheet membrane; Kerdi is probably the best known, but Laticrete also markets Hydroban Sheet, and Nobel has a sheet membrane too.

There are others besides those I've mentioned.

Liquid membranes are easy to apply, especially where you have a lot of inside and outside corners, like niches, etc. It'll typically take two coats, and if the person is new to applying liquid, a mil thickness gauge can be had for a couple of dollars, that'll help make sure the coats are being applied at the correct thickness.

Thanks very much. I talked to the GC and went up yesterday to deal with the issue in person. He's going to take out the existing tile and board, and put in the proper board, as well as liquid membrane around the niches.

Love the fact people around here are knowledgable!

Artemis,

Just note that liquid membrane has to be applied to the whole wall including the niches.

Good luck!

I hope that he isn't charging you for his mistake.

Jafe,

Just start a new thread with your question. I'll do my best to answer your questions on this forum. You'd want others to see it as well, it's always best to get more than one opinion.

As far as compensation, I neither solicit nor accept.

Best, Mongo

Thanks, Mongo. I started a new thread. I, also, changed my display name to ColoExposures. Thank you for your help, in advance.

I recently had a shower and bath tub installed in MA. Durock was used for the backer with Hydroban membrane and Nobelseal TS on the floors. Make sure you pay close attention to how the Durock is prepared for the Hydroban and that all seams are taped and filed with thinset. You should end up with a smooth continuous surface with no gaps, voids or pinholes after 2 coats of your membrane has been applied.

What shower pan/drain system is being used? If it is a copper pan then waterproofing around the drain can be tricky as drains on copper pans are not designed to be sealed. Go to min 14:00 of this video to see how to seal a drain in a copper pan with a mud floor.

https://www.youtube.com/watch?v=8uGeljwFu3c