First of all. There should be no drywall anywhere near a tub. Second, the pics have no scale to judge what is being seen. Pull back and show a shot of the whole area.

why didn't you have them do the cement board too?

Like others said, there should be HardieBacker board there not the sheetrock and follow manufacturer's installation guidelines if you going to DIY. You shouldn't have that big of a space there and caulking is definitely not going to fill that gap.

Have your tile contractor do that he will know how it needs to be done, and if you leave this the way it is, it will cost you allot more down the line, so you better off do this right at this point.

Have the installer show you where the product he intends to use is allowed to be installed over drywall in a wet location. He won't be able to. Also, according to the USG website, this drywall is not to be used behind tile in a wet location. Ceement board is NOT waterproof either. From here you have some options 1- A surface applied sheet membrane such as kerdi or Nobleseal which overlaps from the wall to the tub flange, sealed to the tub flange AND down the side of the tub. 2- Add a layer of CBU (cement board) then a waterproofing layer over that. The CBU should not rest directly on the tub deck. The waterproofing layer should also be adhered to the tub deck. 3- Remove the drywall in the area around the tub at least to the height of the shower head (we normally go to the ceiling) and replace it with cement board with a surface membrane or kerdi board, both of which get bonded to the tub deck and the side of the tub.

Drywall+tub=water damage.

Look at Schluter System products... if you sheet rock it look at using Kerdi Board instead of drywall. Believer in product and you will benefit from it. As above you will want the Kerdi membrane as well.

I think you have to talk to your tile guy and find out exactly what he is doing. I will assume you were talking about caulking the side of the tub and not the 2" gap?

USG sells dry wall for damp locations and if it was properly sealed it wasn't an issue. Is it ideal? No, but with the right seal and installation it is doable. It actually was widely used for years.

Tubs have a built in lip where the board of choice is to go against. The idea is not to rest it on the tub deck surface as it will wick water up into the boards. This actually was an issue with drywall being used. The wall should not sit flush with the lip it should sit in from of the mip as the lip is what backs it. It would be very cheap to simply correct the issue.

I think he left that huge gap as insurance but it is not the correct away to go. If he insists on using the drywall I would have him install a waterproof membrane such as the Shulter system noted above.

Choose your backboard, seal material in a coating or membrane and then a good tile job.

Years ago tiles were placed in a bed of cement on the walls with zero waterproofing except for maybe some roofing felt. 90% of them never had an issue. Now mold is the new bad word and we do everything to prevent it.

Caulking fails at the tub to wall and that is where the water gets into the base wall. Using drywall you run a risk and the better boards remove that risk.

Above comment is correct; tear it out and do it properly because IT WILL LEAK!

Hardee backer is a great product. Drywall in a shower? Crazy.

I am having a similar issue but maybe different at the same time. I had my bathroom drywall redone but was hoping to keep my 1-piece tub surround. However since the walls are not square, it ended up looking like this.

Delighted to see you were able to fix the gap problem! Beautiful tile.

Hello. I see that you completed your tiling some time ago. We have run into the same issue. Do you recall how your tiler sealed the area? The finished product looks great.

Thanks

What is the name of the tile and the deminsions?

Yes, those are Shluter trim strips. I bought them for my bath as well.