This is the final post about drywall screws used in places they should not be. To reiterate, this is new construction, and all three posts came about because of a single pre-drywall inspection on a $1.5 million house.
The reasoning behind building a new house, and an expensive one, is to get what you pay for. You are hoping not to inherit pre-existing problems or those left over by previous homeowners. That is good logic.
Which brings us to drywall screws.
This is a view of the master shower, large, two shower heads, and a seat at one end.
Notice the black iron pipe sticking out from the seat?
That is for a steam unit to be installed just behind. In addition to being a shower, this will be a steam room too.
The shower pan is properly lined with the typical 40 mil PVC membrane. It is a good product. The seat is strong and the shower is properly framed.
Notice, if you can, how well the membrane is attached. There are many holders. And this is important. That membrane is essential to the proper functioning of the area, and the tile on the floor, lower walls and seat. It is the only waterproof seal!
So far, so good.
Until you look closely! A good product is only as good at it's installation. And this is a DISASTER!
1. The membrane is rumpled on the floor.
2. There are cuts everywhere. The membrane should not be cut and fastened to itself.
3. The seat should be a single piece and where it overlaps the membrane running up the wall it should be glued, NOT PENETRATED. The fewer the penetrations the better.
4. It should only be fastened at the top, and then with galvanized or aluminum nails with large heads.
5. There are a whole bunch of drywall screws holding that product into place! And they are screwed down really, really tightly. They are everywhere!
6. This is going to be a really hot, really moist area! Drywall screws will rust, pop through the membrane and cause the studs behind rot!
So, how is the shower liner best held into place? WITH A PROPERLY-INSTALLED CEMENT BOARD! And one NOT put up with drywall screws or interior drywall nails!
If you research how to install shower pan membranes, dozens of sites pop up. Many are provided by ceramic tile manufacturers! Why? Because when an improperly-installed pan fails (meaning the membrane), they don't want their tile to be blamed! Here is what this tile manufacturer had to say about shower liners:
"The sheet membrane is sealed to the top of the drain base. That means water is routed from the liner sheet to the lower drain holes in the special shower drain. That's how water that seeps through the shower floor gets in the drain and not in the subfloor. The liner is folded in the corners so there are no cuts. But to get the liner over the curb, there must be some cuts. One way to seal at the cuts is to use special dam pieces which are glued in place at every corner to perfectly seal at joints. Also no fasteners should be put in the liner except near the very top of the liner and on the outside of the curb, and then only with galvanized or non-rusting, large-head fasteners. The shower liner is always installed over a sloped base to insure that water never pools in the shower floor. Water that makes it to the liner runs right toward the drain. Don't even think about installing a shower pan liner over a flat floor. That's a guaranteed problem ceramic tile shower."
Their step-by-step guide is excellent! Notice the last two lines. Having just read that you probably know more about how to install shower liners than the "professional" who installed this one.
My recommendation: Always have a home inspection. Always have a pre-drywall inspection. It is the only way to see this example of work that will definitely be a problem down the road for somebody.
Including YOUR client...
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560