Construction sealants are designed to keep air, vapour/gas or liquids from passing through joints or cracks in the building envelope of any structure. Sealants or caulking are synonymous but not to be confused with sealers. Sealants maintain the integrity of the building envelope and prevent damage to the rest of the structure. They are relatively inexpensive relative to the importance of their function in maintaining that integrity so choice of the correct sealant and proper installation are important considerations. There are many generic categories of sealants and all have distinct purposes or areas of utilisation that must be understood prior to sealant selection.
Silicone based sealants can be used for many diverse construction applications and are considered to be high performance sealants. Those applications include not only sealing the building envelope but will also include bonding or adhesive applications as well as structural glazing. Depending on the type of silicone chosen, suitable substrates will include glass, metal, concrete, masonry, some rubbers and plastics, stone, ceramics and many more. Silicones can withstand the widest temperature range compared to any other conventional sealant and will maintain a great degree of movement capability throughout its lifespan regardless of the service temperatures involved.
Polyurethanes, commonly referred to as Urethanes are also considered to be high performing sealants. They can perform in many of the critical areas where silicones are used and have some advantages as well as some disadvantages over them so once again it becomes critical to understand the service demands of the joint prior to choosing this or any sealant type. Urethanes are possibly the most versatile of the sealants available currently when price, performance, colour selection, abrasion resistance and longevity are all taken into account.
This is a relatively new category of sealants, commonly referred to as “hybrids” but more accurately they are MS (modified-silane) Polymers or SMP’s (silyl-terminated polymers). They are solvent and isocyanate free with extremely low or at times no VOC’s. Many can be used as adhesives or sealants or as both at the same time as they have a very high “green strength” compared to most adhesives. They are not a blend of silicones and urethanes as they are often portrayed, rather they possess the best attributes of both and are quickly becoming more commonplace as their attributes become better known.
Used primarily for window perimeters, siding and eavestroughs. They are extremely fast skinning and more moisture tolerant than most sealants. Most thermoplastics are available in a vast selection of colours to match today’s expansive window and siding market offerings.
There are other types of sealants without the same high performance aspects that are generally used in areas that are less demanding or critical. These sealants include butyl and acrylics. Also available are specialty sealants such as polysulphides, acoustical sealants, high temperature or refractory sealants and others for certain niche applications.
Tools and Accessories
Application tools, such as caulking guns (cartridge, sausage, bulk, pneumatic, cordless electric), joint tooling spatulas, specialty nozzles, cleaning agents, joint backing materials/applicators, follow plates, caulking warmers etc. are all available through CDS.