If the cement board was installed according to the manufacturer's specifications i.e. the right screws, tape and cement was used, there is nothing wrong with it.

Here is the LINK for proper installation

" Should I be concerned? "

I would be. From what I know, cement board is not effected by water. It will let water pass thru, wick water and is not "waterproof". I would want a topical waterproofing if cement board were used.

The manufacturer's specification in this case (Durock) includes specification of using a sealing membrane or applied waterproofing coating for waterproof installations. So, unfortunately, there is everything wrong with your contractor's installation technique. It may not leak badly, but it will leak.

Here's a quote from the manufacturer: "Waterproofing If waterproofing is desired, use USG Durock™ Brand Waterproofing Membrane or USG Durock™ Brand Liquid Waterproofing Membrane. See USG Durock™ Brand Waterproofing Membrane submittal sheet (CB595) or USG Durock™ Brand Liquid Waterproofing Membrane submittal sheet (CB817) for product information.

@rwiegand is there a chance that white paint on the cement board is any type of waterproofing ?

No, that is thinset. The waterproofing is typically a Red if Redguard, Or Green if Aquadefense. I have not heard of any white waterproofing coatings.

Are you sure they didn't put poly sheets or felt on the wall under the cement board? That's the old school way.

@rwiegand is correct. The instructions call for a waterproofing membrane "If waterproofing is desired". That makes it sound optional, but it's not optional in a wet area such as a shower. It needs to be waterproofed in a shower. The board remains dimensionally and structurally stable when it gets wet, which is what is meant by "water durable" but it's not waterproof the way some boards are. The issue is that the board will absorb/wick water and then will dry to the back side - so inside the stud space. The board itself won't mold, but the wall cavity won't be so lucky

Poly under the board - as @Seabornman suggested - was an old school way, but it trapped the water between the backerboard and the tile - not at all ideal and it isn't the correct way to do things anymore.

Here's the problem: You are now in a position where you are going to be arguing about this with your installer - to would have to rip it all out to do it right and eat the cost. It's not going to happen unless you still haven't paid him.

I think all shower / tile installs should be photographed before any tile goes up and nothing moves forward until questions about waterproofing / construction details are answered.

In a regular shower, when edge guard board is used, the requirement is to waterproof the joints and screw penetrations by filling joints with latex-fortified mortar or type 1 organic adhesive and alkali-resistant fiberglass mesh joint tape should be used. That is the typical requirement for a regular shower... If this was a steam room, it would be a different requirement.

Not sure what they used to protect the joints in this case, hopefully, they followed the installation specs.

I was inspecting a job, and they didn't use anything; they hung the boards and tiled it right over it.

@GN Builders

The installation instructions that you linked to do not really support what you say.

This product doesn't have any inherent waterproofing - the same as most other concrete backer boards. If water gets behind the tile, and it will, the backer will absorb it and dry to the interior stud space. And while this backer board won't mold, the stud space will.

I think you will find that TCNA guidelines call for the use of a waterproof membrane in interior wet areas unless the tile backer is inherently waterproof.

With Durock, I think it's a case of "we've always done it this way". It's not fun to install, but it's a very durable product and a high-quality tile backer. The product has been around for a long time, and installers have been putting it up without a waterproofing membrane for a long time - but that doesn't make it right. Homes have gotten tighter, and mold is something we are more aware of.

Is it going to leak? Probably not (unless there's something other than just no waterproofing). Is it done right? No, the wet areas should have been coated with waterproofing.

Again, though, this should have been addressed up-front - not once the tile went up.

You hired poorly. There is no "fixing" that, or backing your way into a good install. You have to hire better on the front end.

@Minardi

" You hired poorly"

I think that's harsh and unnecessary.

To begin with, although it's not "right" - it has been a common practice. Unless there's more to it that what was presented, it's not egregiously bad like some things I've seen on here.

Second, they are a homeowner, not a GC. They should not be expected to have detailed knowledge of materials and practices. There are lots of tile backing products out there, it's the contractor's job to know the details. And unless the homeowner just picked these guys up off the Big Box parking lot labor pool, they had every reason to expect that it would be done properly.

I suspect that these are knowledgeable installers who would be very surprised to know it's not right.

Shower surround problems litter the internet. Just as many opinions on how to construct them correctly. In general, you want to build something once, to be durable, and keeps risk of problems low. Building construction constantly advances and learns from mistakes, and new products have evolved. In that sense, waterproofing should be on those walls. It can be a polyethylene plastic behind the CBU, or fluid or mechanically -applied on the front of CBU.

But, there are 3 big picture things at play here: code, best practices, and contracts.

- U.S. code does not specifically call out for wall waterproofing. What it says is the wall finish must be nonabsorbent, and joints must be water-tight. However, it does call out for a shower floor liner though. Code is a finicky subject. You can choose not to build to code, but what it can be is leverage against a contractor to do something per code. Sometimes sections can also be interpreted in a couple ways (to each parties advantage). So the floor of the shower must have waterproofing, the walls can be interpreted as the grout is not sufficient.

- Best practices would be TCNA recommendations. They call out for wall waterproofing, and detail how the tile and tub flange interact. But a contractor is free to say their method is best practices, the ole' "been doing it for 30 years like this and never a callback." Most probably don't even know what TCNA is.

- Your contract, if experienced in buildings and/or with sophisticated contractors, should specify all products, details, and workmanship. But typically they are very general and vague. This is what any problem boils down to, what did it say, who pays, who's at fault. Did you know what you wanted before signing, are you getting it, and if not why.

Last year, we did a whole-house remodeling. We gutted 2 bathrooms, the home was built in the early 60s, original owners, 5 people in the family for the duration of the 1st-20 years, the tile backer was drywall with paper taped joints 1 coat and tile over it... have to say the tub surround area was well maintained, all corners etc were caulked every so many years per homeowner.

Not a single water intrusion sign was beyond the drywall, along the perimeter, or near windows, except was a slight sign of water staining on the outside of the tub on the plywood floor where the shower door was.

The secret is to regularly maintain wet areas, check corners, around the tub perimeter, etc, and never use grout in the corners or adjoining areas to other materials.

Installations of the 60's era still were thick mud beds, so that was remodeled sometime in the 80's when oil based mastic and drywall was used. Oil based mastic is not today's modern water emulsion that re-emulsifies. Bragging about no damage isn't the flex you think it is.

Nothing to brag about, just stating the facts, no thick mud beds, none of that... they original owners... homes that were built in the 1800-1900, yes, thick beds, steel wire-mesh on walls, etc, done plenty of them also

@Minardi I think my friend, you have your days mixed up a bit, thinset has been used since after World War 2 if I'm not mistaken, you find thinset in late 1940-1950s homes.

@GN Builders

I've worked on a lot of older homes also - some that predated indoor plumbing.

I usually come away thinking, "They don't build them like they used to -- and it's a darn good thing that they don't."

I've worked on 125+ year old homes that had sand footers, no headers in openings on load bearing walls, overspanned joists, etc. Of course the house was still standing - but I sure wouldn't use that fact to argue that headers and proper foundations aren't really necessary.

I've seen tile over drywall, tile over greenboard, tile over plaster - and certainly tile over Durock. I don't think you are trying to make the argument that tile over drywall in a wet area is ever acceptable - at least I hope not.

The way that contractors understand tile in wet areas has changed. We should never assume that the tile is a waterproof surface - because we all know that grout will crack, caulk will dry out, walls and floors will settle and maintenance is never 100%. We don't want to design and build a shower area that we know is likely to fail - and then fault the occupants for not showering with a caulking gun.

When we start with the assumption that water will get behind the tile, then the "drainage plane" is not the tile, It's the backer beneath the tile. And Ideally, for reasons already mentioned, that doesn't ever rely on caulk alone to achieve that water tight status. What's more, the backer must always remain structurally and dimensionally stable when it gets wet and must not support mold growth - which eliminates drywall, greenboard, and any type of wood.

In addition, assuming water will get behind the tile means that the backer must not transmit water vapor into the wall cavity. That requires the backer to be inherently waterproof or have a durable waterproof coating. Plastic behind the backer board has been used in the past, but it traps the moisture on the wrong side of the backer board.

Old methods for building showers remind me of pre-1970's cars. Those cars were designed and built with the assumption (magical thinking) that they would not be involved in a crash. A crash was entirely outside the scope of design and engineering - no seatbelts even. If they were involved in an accident, any resulting injury was the drivers' fault and responsibility. We now assume cars will crash and design them accordingly.

Jake, I couldn't agree with you more on many issues. We all know lots of new practices are used nowadays, and they keep coming up with more and more stuff its hard to keep up, and the fact remains that gypsum backer boards are still being used in new construction on many developments, and customers still have certain budgets, some drive Hondas and some drive Caddys, same in construction some have tight budgets and some have money that burn a hole in their pocket, and no matter what it is or what practice is being used it should be done the right way according to manufacturer specs.

Unfortunately, there are many hacks out there, some fly-by-night, some just cut corners when customers don't know any better, or homeowners hire jacks-of-all-trades in a Home Depot parking lot, which is very common in my area, and I'm talking about homeowners with a million-dollar homes.

As older houses go, I never ran into sand footings but I did ran into a few where they put mortar right on the shale, 8" block on top of it and fill core with mortar and that was your footing but I'll tell you there was not a single hairline crack in that foundation, not to mention the outside was never parged also.

As the headers go, I never ran into houses without headers in load-bearing walls, but seen many different and interesting practices on how the loads were transferred down below.

Here is one example from a house I did a complete remodeling on. The house was built in the 1800s, and the mid-section of the beam carrying portion of the second floor, brick brick-filled exterior wall ( I believe that method was called brick nogging), and a slate roof were supported by a metal rod; the rest of the load was transferred to the end points. So you find many interesting things.

As the cars go, I wish I had held on to the cars I owned in comparison to what they make today, fuggetaboutit I don't even wanna touch that subject lol.

Have a good one!

You aren't picturing thinset. You are picturing fat mud. TCNA W241-24. Different installation methodology than a thin bit of stickum over a thin bit of cement board or other stuff.