Hello Everyone,

My wife and I just purchased a 1760 colonial in New England. The weather here is beginning to get quite chilly at nights, and by morning, is in the low 40's. We have no vent fan in the second floor full bath and my wife and I both take hot showers. I do plan on installing a vent fan in the near future, but that isn't the reason for this thread.

I couple of weeks ago, we found a dead mouse in the bathroom that was stinking it up quite horridly. After I removed the carcass, my wife stuck a box of baking soda to help remove the smell. The box was placed inside the vanity, doors closed.

A couple hot showers later...

I am in the kitchen, below that bathroom, and in the plaster ceiling, I see a rather large brown stain appearing. I run upstairs, open the vanity and it is drenched. There are water droplets on everything. The baking soda box is completely saturated, the boards in the bottom of the vanity are wet, as is the false floor below it... likewise, the plaster below that is wet.

I clean everything out expecting that the faucet is leaking. It isn't. I let it run for a few minutes on hot and cold, checking the valves and drain. No dripping, and nothing remotely close to the level of water expected. Also, at the time of the brown stain being spotted, there was no humidity in the bathroom.

So, my question (finally) is:

Can baking soda, when sealed within the vanity, during very humid conditions, absorb so much water that it begins to expel it like a super saturated sponge?