Two types of caulking are available for home repairs: water-based non-acrylic caulk and silicone caulk. Since water-based caulk can be messy to work and prone to staining, aging and mildew, many people prefer working with silicone-based caulk as it is easy to remove and provides a better water-tight seal.
By far the biggest drawback of using silicone caulk is the odor. Known to cause dizziness or lightheadedness because of its overpowering smell, many contractors chose to use a more expensive, odor-free caulk. Typical silicone caulk has an aroma akin to extremely strong vinegar. This odor will dissipate, but it will take at least two days.
Porous Surfaces and Gaps
Silicone caulk does not adhere as well as acrylic-based caulk for areas that are porous because of its rubber-like flexibility and oil-based formula. Keep in mind that silicone caulk is best when used in an area that requires a good deal of give. When it comes to filling gaps, consider investing in foam backing rod that fits inside of the caulking area. This is a flexible foam tube that works much like insulation by filling the space between the tub and the tile. It is waterproof and keeps you from having to pump a gap full of caulk, thus limiting your exposure to the fumes and saving you money.
Silicone caulk is made by taking silica sand and transforming it into an oil-based polymer. This is what gives the caulk a great deal of give. This is especially needed in tubs that move a good deal as the average bath with water weighs more than 300 lbs. when full. The oil eventually evaporates over the years, but after application, silicone caulk will not take paint. If you plan on painting over your caulk, then go with a water-based acrylic caulking.
Silicone caulk requires a certain degree of moisture in the air to set completely, which means it can take much longer to dry in drier climates than the acrylic-based caulk. Prepare to spend an extra day waiting for your caulk to dry if you live in an arid climate.
Silicone Solvent Remover
For old silicone caulk that is proving difficult to remove, a solvent will be required. Some silicone solvent removers will work on silicone caulk that is weeks old. This solvent, however, takes from one to six hours of placement before it will dissolve the silicone sealant. Use caution when placing the solvent on silicone as it will dissolve some types of sealant and tubing that are not silicon based. Be sure to test a small area with your solvent before applying it and read the manufacturer's directions carefully.