Latex Caulk Limitations

Indoor/Outdoor Use

• While you can use latex caulk outdoors, latex is particularly vulnerable to sunlight and quickly loses its durability. Temperature extremes also cause latex caulk to break down more rapidly. Thus, latex caulk is best suited for indoor applications where the temperature remains relatively constant and the caulk is not exposed to direct sunlight. In the event you must use latex caulk outdoors, the University of Nebraska-Lincoln recommends painting the caulk. Latex caulk holds paint well, and the paint provides it a measure of protection from sunlight and the elements.

Adherence

• Different types of caulk adhere best to different materials. Latex caulk is ideal for sealing gaps and cracks that remain stationary at all times. Because latex caulk is not particularly flexible, it isn't suited for sealing areas that regularly expand and contract, such as hardwood floors and other wooden structures. You also cannot use latex caulk to seal gaps and crack in metal structures. Latex caulk does not adhere to metal.

Durability

• The length of time your latex caulk will last depends on a variety of factors, such as where the caulk was applied and the conditions in the area. Latex caulk applied indoors, for example, will almost always last longer than caulking applied outdoors. In general, latex caulk lasts anywhere from two years to 10 years – making it less durable than certain other types of caulk, such as polyurethane and silicone, which can last 20 years or longer.

Shrinkage

• Unlike silicone caulk, polyurethane caulk and water-based foam sealant, latex caulk shrinks as it dries. While latex caulk shrinks only 5 to 10 percent, this can still leave gaps and cracks around your home improperly sealed – resulting in higher energy bills. If you use latex caulk in your bathroom, shrinkage can leave your subfloor subject to water damage. It can also provide a space for mildew to grow beneath your caulk line. If you notice black spots on the latex caulk in your bathroom, mildew is already growing behind your caulk, and you must remove and replace the caulk line as soon as possible.