As standard procedure for every home inspection that I perform, I check the toilets to make sure they're properly anchored to the floor. Almost every time I find a toilet that's loose, I also find missing caulk at the base of the toilet. The two go hand in hand.
The thought process behind not caulking the toilet to the floor is that if the toilet leaks at the floor, you'll quickly find out about the leak as long as the toilet isn't caulked. If it is caulked, the thinking is that if the toilet flange leaks, you'll end up trapping water between the toilet base and the floor in an area that you can't access.
In reality, toilets rarely leak on to the the floor. More often, they leak through the floor around the flange. I've found plenty of toilets that leak down in to the basement, but very few that leak on to the bathroom floor.
There are two great reasons to caulk your toilet to the floor:
- Caulk prevents a fouling area. If mop water, tub water, or something even worse (I have a son who is potty training right now...) gets underneath the toilet, there is no way to clean it up. Caulking around the base of the toilet prevents this from happening.
- Caulk helps to keep the toilet secured to the floor. As I mentioned before, toilets that are caulked at the floor are rarely loose. Caulk does such as good job of keeping toilets secured to the floor that you could probably rely on caulk alone to keep a toilet secured... not that I would try this.
Some people prefer to caulk all around the toilet and leave about a one inch gap in the caulk at the back of the toilet to allow water to escape out in the event of a leak. It's already tough enough to caulk behind a toilet, so if this is what you want to do, God bless.
Reuben Saltzman, Structure Tech Home Inspections