If you are planning on reinforcing or replacing a toilet, then you’ll need to apply an appropriate sealant. Either silicone and acrylic caulk will seal toilet edges and keep water from seeping under the flooring.
Each has a particular advantage that the do-it-yourself-er should consider.
Acrylic Caulk Features
Acrylic is the most popular consumer choice because it has multiple uses around the house, like filling in cracks around windows and doors. Acrylic caulk is useful for bathroom projects like toilets due to how easy it is to use and clean up.
Silicone Caulk Features
Silicone caulk is clear and forms an invisible seal once applied. It is often recommended for bathroom work because it is water-proof and inconspicuous on tile.
However, Silicone can be very messy, and that includes its smell.
Silicone has a rubbery finish so it retards moisture better and lasts longer than acrylic caulking. This would make it the best type of caulking for the base of a toilet due to its ability to lock any kind of moisture away from the flooring.
If you are planning to paint over the caulking, acrylic is your best choice. Silicone's greatest strength, its water resistance, also makes it resistant to paint.
Another disadvantage of silicone is that it is difficult to remove. If you are planning on replacing your toilet anytime acrylic would be the better choice.
Use a brand of caulk with mildew resistant additives designed specifically for bathroom use. Both surfaces need to be dry before either caulk to help ensure a permanent seal.
If the old caulk around the base of the toilet is silicone, it will have to be scraped off with a razor blade or similar implement before either new sealant is applied.