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What Is Elastomeric Caulk?

Keith Allen

Elastomeric caulks are used to seal cracks and crevices. Homeowners use caulk to seal openings where two building materials join. Among the area where caulk is used is the joint between a window frame and siding on the exterior of the home or along the edge of a bathtub where it joins the wall.

Caulk is used to seal the cracks that form where two building materials are joined.

Elastomeric caulk possesses elastic qualities, which make it a versatile caulk product.

Caulk Materials

Manufacturers produce elastomeric caulk from a number of products including polyurethane, silicone and polysulfide. Any of these materials produce caulk products with the elastic qualities necessary for the product to fall into this category.

Elastomeric Properties

Elastomeric caulks are design to expand and continue to fill the cracks or joints even if the building material shifts. There are limits to its ability to expand. Most better quality elastomeric caulks can expand to about double the original caulk bead and still maintain adhesion to the building materials. The caulk maintains a pliable consistency and doesn’t dry out. This prevents cracks in the caulk which can occur with less elastic caulks are used.


As of 2011, premium quality elastomeric caulks run about $4 per tube. The material is available in most hardware and home improvement stores as well as at lumberyards. Not all products are identified as elastomeric but are more commonly identified by the principle ingredient.


Follow the manufacturer’s instructions when using elastomeric caulk. The application procedures do differ from product to product. Some require porous surfaces such as bare wood to be primed before the caulk is applied. Others have a specific drying time before painting over the caulk. In the case of solvent-based elastomeric caulk a chemical solvent is used to shape the caulk bead and to clean any tools.