Been scanning different builder Instagram pages and I'm regularly seeing people posting pictures PROUD that they are setting tile to cement board without any waterproofing. Now you as a homeowner obviously care most about what the shower looks like finished. That is important, but to us that isn't as important as having a waterproof shower. We geek out on water proofing because we know how important it is. The most important part of the process happens before tile is even set. Cement board, tile, most grouts...aren't waterproof alone. So when you have black mold around the base of your shower, that's a leak...due to improper installation. We get the question..."can you fix that?" the only way to fix a leaky shower is to tear EVERYTHING out....and start again. Many guys will tell you they can fix a leaky shower...I'm telling you that you mine as well set your money on fire then pay for a shower "repair" We use waterproof foam boards and membranes and I'm not saying it's the only way to do it....but comeon,, It's 2016 and if you're in the tile game you need to keep with the industry trends. We hear all the time, 'That Schluter stuff doesn't work' O that's why the company offers a 10 year warranty? We've had nothing but success with Schluter systems and we are experts with it. I suppose my point is that if you're having a shower built or even a tub surround, be aware of how your tile guy is water proofing things. If he's using hardi backer or cement board telling you that it's waterproof, he's uninformed and you should ask him to leave.