" Everything I’ve read has said to remove the grout and reapply "

Correct, remove and replace the grout.

" How do we know if there is mold growing behind the tile? "

Grout is not nor ever was intended to be waterproof, water passes thru it to the pan and then to the drain in a properly constructed shower.

" They also used grout for all the corners - which of course started cracking soon after we moved in. "

Grout needs to be removed before silicone is place in all changes of plan.

How much curb appeal can you stand. Paint the brick white, new metal roof and thicker columns.

Thank you, Millworkman!! I don't have great pics of the shower install, but are you able to tell from the attached if it was properly constructed? I know that after the water test was completed, they covered the pvc pan liner with concrete - but I do not have a photo of that.

According to the manufacturers installation the GlasRoc panels are "water resistant", not waterproof. Were it me I would want waterproofing over the top of the boards as well as all the joints taped and spackled with thinset. So, no in my humble opinion the shower is not built correctly.

In fact just looking at the instructions again I saw this which makes my point above even stronger:

Special Notes: • A water-resistant barrier is required, before tile application, on the interior side of an exterior wall. This is especially important in tub and/or shower enclosures, due to the higher humidity levels and potential vapor drive from the interior space to the exterior. A water-resistant barrier is recommended, before tile application, when the wall is an interior wall. This includes when the tub and/or shower enclosure is an interior wall.

LINK to the instructions.

Michelle:

Unless the walls were taped and waterpoofed after your pictures were taken, your builder failed to follow Certainteed's installation instructions. If the tile is removed and it isn't installed properly, replacement is on him and vice versa. Replacing the tile would only be a little more work than replacing the grout.

Show him Certainteed's instructions. He's not arguing with you, he's arguing with them.

A rubber pan, flat on the floor, with the preslope on top, is a fail. Even if it held water, it is a fail. And it should have been failed at the leakdown inspection. Not to mention the rest.

Thank you!! I appreciate all your help. This build has been a nightmare, so I'm not surprised if things weren't done correctly. I did find a photo of another one of our showers right before tile installation and it appears they used RedGuard ? on the lower part of the shower. I don't have a single photo showing they taped any of the joints. Should I be concerned or will the RedGuard help prevent water issues?

Minardi, would you mind sharing why the rubber pan with the preslope on top is a fail? I just want to be as informed as possible when I speak with him.

No. Moisture sandwiches cause issues.

" Should I be concerned or will the RedGuard help prevent water issues? "

If the joints are not taped and spackjled with thinset the redguard is almost useless. If the RedGuard does not cover ever square inch if the GlasRock properly taped and spackeled with thinset it is useless.