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What forms of caulking compounds area available?
Caulking compounds come in several forms including:
• disposable cartridges that fit in caulking guns
• pressurized caulking cartridges that need no caulk guns
• aerosol cans
• squeeze tubes
• peel and stick
• filler materials (rope caulk, backer rod)
Caulking is intended to fill cracks less than 1/4” or 3/8” wide and must adhere to its material to work properly. Different compounds vary in how well they adhere to different materials and in their resilience, durability, flexibility, cost, ease of use and clean up, color, or ability to be painted. When caulking two different materials, choose a compound that will remain flexible.
Different materials expand and contract at different rates, creating joint stress. Large/deep cracks need backer rod, rope caulk or closed cell foam or fillers (sponge rubber, oakum or caulking cotton). Use metal, rigid foam, wood or drywall for larger gaps.
Some compounds may have special properties, such as mildew resistance. High-temperature caulks are used around areas that get hot, such as chimney flashing. Some caulks will bond to two different materials while allowing flexibility.
Some foams expand more and may create pressure where pressure is not wanted such as around window and doorframes. Metal and porous materials like masonry or cement require special caulking compounds and some compounds require a primer when used on certain materials.
What are the different types of caulking compounds? What are their characteristics?
Caulking compounds are either water-based or solvent-based. Clean up water-based caulking compounds with water before they cure. Clean up solvent-based compounds with solvents and ventilate well.
Typical caulking compounds include
• latex, acrylic latex
• oil or resin-based
• urethane or polyurethane
• silicone – household or construction
• polyurethane expandable spray foam
• water-based low expansion spray foam
• butyl rubber
• closed-cell foam or rope caulk
Newer caulk products include synthetic-rubber, modified-silicone polymers, and polysulfides. Newer caulks may also be hybrid caulks combining the properties of several caulk types to create a more versatile product. Because company products vary, read the labels and uses for each product. For example, acid-cured silicones work best on nonporous surfaces such as glass and glazed tile. Neutral-cure silicones work better on wood and metal.
For more information on the general characteristics of each caulking product, go to Weatherizing Your Home: Caulking at http://www.ianrpubs.unl.edu/sendIt/g1642.pdf or to U.S. Department of Energy (DOE) Energy Efficiency and Renewable Energy - Caulking http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11270 . Read the labels on the products for specific characteristics.
Read and follow manufacturer’s instructions. Choose the appropriate type of product for each job, and a brand of quality caulking with a minimum life span of five years. Very durable quality caulking may be more economical over time and is important for areas exposed to severe weathering or that are difficult to reach.