During deconstructing and cleaning things up we ran into a lot of halfhearted patching and cover-ups. While I am amazed how someone could conclude that hiding a problem behind another layer will solve it, I get to learn where the real problem areas are in an old house like ours.
One good and recent example is the bathrooms. We were in the process of removing the plaster and lath in the first floor bathroom and found a drop ceiling that covered up a big hole in the original ceiling.
It did not take us long to figure that that hole was caused by water damage. Not only that, but looking at the rot in parts of the lumber and framing, it was obvious that there must have been persistent water leakage into the ceiling from the 2nd floor bathroom.
“Water accumulation inside the building presents risks to occupant health as it can lead to growth of mold, support pest populations, and cause other IAQ [Indoor Air Quality] problems. Accumulation of water inside the building can also be detrimental to building durability by causing rot and deterioration of building materials and by enabling damaging pest populations.”
Source: buildingscience.com, Interior Water Management
Having seen firsthand what damage water can cause, we begin to think about preventative measures for the remodeled bathrooms, which, because of their water loading, are considered ‘wet rooms’. One key strategy is, I believe, to make sure that any future leak is immediately noticeable, rather than having water infiltrate into the structure and only notice it days, weeks or months later.
Another strategy is to anticipate spills, splashes and misdirected water. Tiles, preferably recycled or reclaimed tiles, are an obvious choice for the bathroom floor as they are considered water resistant. We further should consider a water resistant baseboard product that is sealed to the tiled floor and a floor drain. My hope is that this will help with the management of the accidental water. This is still under negotiation, since my lovely wife is not too keen on having a floor drain in the middle of the bathroom floor.
The typical paper-faced drywall products have, as I have learned, no place in this wet room environment. Cement board or fiber cement board are the recommended choices. If you would like to learn more, I recommend the Interior Water Management information sheet published by buildingscience.com.
From our experience, it seems that many problems of this type are caused by slow leaks from partial failure of a seal at the base of a toilet. This can easily rot the subfloor and cause mold and damage below.
Tile and cement board work well for spills and splashes, but do not help with toilet seal issues. Our suggestion is to make sure that the toilet is absolutely level and solidly seated. Inspect it periodically to make sure that it hasn’t come loose at all. When you inspect, if you haven any doubts about whether it’s still level and solid, you should probably pull it and replace the seal. It’s cheap insurance against long-term damage.