Blindsided By Mold: A True Story About A Bathroom Renovation Gone Bad – So Very, Very Bad – Part 2

Photo by

In our previous blog, “Madeline” had discovered she had a mold problem – a BIG BAD mold problem.  The source of the moisture leading to this situation seemed to be the master bathroom shower, where a firm hand press against the tile proved that the wall behind it had indeed gone soft.

After getting some idea of the magnitude of the mold growth problem in her home, Madeline’s first scream for help was to the insurance company.

“Does our insurance cover mold damage?” she asked.

“Mold?” replied the adjuster.  “Oh no.  You have no mold coverage.”


Here’s an important factoid for homeowners.  Most homeowners’ policies do not cover mold damage – at least not from a prolonged or overlooked moisture problem.  They typically cover mold damage that results from a single, catastrophic event such as a pipe bursting and the resulting flood, but not a gradual condition.

What Lies Beneath….
Madeline’s next call was to the contractor – a trusted friend of the family – who had renovated her master bathroom 10 years earlier.  We’ll call him “Fred.”

“He didn’t want to believe that the water was coming from the shower.  He really believed there had to be another explanation.  But I made him knock out part of the shower wall so we could see what was happening when the shower was turned on.  That’s when we saw water pouring into the wall.”

It didn’t take Fred long to see what the problem was – two problems to be exact.  And the look on his face told Madeline that he was, himself, sickened by what he saw.

First, upon dismantling the shower, it was discovered that the shower liner (an essential part of a tiled shower installation) was cut short on one side – the side adjacent to the bedroom with mold on the wall.

A properly installed shower liner in a new construction home.

Shower liners are flexible, waterproof sheet membranes, typically PVC (poly-vinyl chloride) that are installed above the subfloor of a shower.  A layer of cement mortar goes over the liner, followed by the tile – the only part the homeowner will typically ever see.

Liners should be cut to size so that they come up the sidewalls of the shower to a point that is above the shower curb – usually 5 inches.  If this isn’t done, trouble will most certainly follow because (drum roll, please) tiled showers are not are not waterproof, they are water-repellent. Let me say that again.  TILED SHOWERS ARE NOT WATERPROOF!  Thus, the mortar beneath the tile floor where your little tootsies are, is typically wet, even saturated most of the time, assuming the shower is used regularly, which Madeline’s was.

The role of the shower liner is to catch the water transferring through the tile floor and direct it down the shower drainpipe.  If, however, that liner is cut too short, water can and will spill over into the adjacent wall space – which is exactly what Madeline and Fred saw when they turned on the water in the partially dismantled shower.  I believe the word Madeline used, was “waterfall.”

But a short-cropped liner wasn’t the only installation sin here.  The tile had been installed directly onto drywall instead of cement board, which is what should be used behind a tiled shower wall.  Keep in mind that drywall is basically paper.  And what happens to paper when it gets wet?  It soaks the moisture up and breaks down.

In short, there was nothing of any substance in the shower to stop this daily flow of water between the shower and the wall space.  It was, however soaked up by every bit of porous material it encountered, including wall studs, floor joists, wood flooring, etc.  Madeline didn’t realize it, but this area of her home was not only moldy, it had become unstable.

A Sad and Scary Truth
This is a lousy thing to lay on homeowners, most of whom never give much thought to their beautifully tiled showers except …well…to admire how beautiful they are.  But what happened to Madeline happens all the time.  The only thing that is unusual about Madeline’s situation is that it took her nearly 10 years to discover.

However, if you spend as much time as I do eavesdropping on conversations between people in the construction industry, you’d realize how common this problem is.  Plumbers know it, builders know it, mold remediators know it, tile installers know it, and unfortunately many homeowners know about it too, only they usually find out too late.

So, there was Madeline, face-to-face with a contractor, a trusted friend, wondering what would happen next.

Read more about green homes a


Author: Trish Holder of Greenspiration Home LLC

Share This Post On

Submit a Comment