Dow Corning sealants are featured in the weatherproofing of the glass curtainwalls of the Time Warner Center in New York City. RSG Caulking & Waterproofing, one of the largest caulking installation companies in New York, has successfully used Dow Corning sealants on almost every project for the past 22 years.
Because the physical
condition of a building can change greatly over time due to external forces
such as sun, wind and rain, choosing materials that will maximize the life and
appearance of the structure, while minimizing the amount of damage, is crucial.
This is especially true in selecting a sealant. Following are some of the most
common aesthetic issues to consider.
- Dirt Pick-Up –
Accumulation of dirt on a sealant’s surface is particularly prevalent on
construction sites with large amounts of dust. The actual amount of dirt
pick-up will vary with exposure conditions, but excessive pollutant
contamination will result in lower durability and weaker bond strength. To
avoid this, choose a sealant that can tolerate higher levels of
- Chalking – As the
substrate begins to degrade and erode over time, the surface becomes more rough
and porous, which leads to a loss of surface gloss and color. Chalking is most
observed in organic sealants that are initially black or brown, but later
transform into a light gray or beige. This does not occur with silicone or
- Change of Color –
Color change can result from factors both inherent and external to the sealant.
Incompatibility of the sealant with other building materials is a contributing
factor. Materials with high incompatibility levels include low-molecular-weight
polymers, antioxidants or tar. A sealant that is compatible with a variety of
other substrates is preferable.
- Surface Crazing – A
variety of factors, including sunlight, environmental stress and aging, can
cause cracks in the sealant’s surface. This is especially common with organic
sealants. Generally, sealants with higher polymer content are more durable and less
subject to crazing.
- Fluid Migration –
Fluids can migrate from a sealant to the substrate, creating a dark “wet” band
look around the joint of the sealant. The extent and rate of fluid migration
varies with the type of sealant. Cheaper, less formulated sealants are the most
prone to staining and fluid migration.
- Other Environmental Factors
– Oxygen, ultraviolet radiation, climate/temperature, microbial growth and
other environmentally-induced mechanisms can contribute to the fatigue and
stress that degrades and lowers the overall bond strength of the
While aesthetic issues cannot be completely avoided, they can be mitigated
through prior knowledge; selection of high-quality, high-
performance building materials; and working with a reputable manufacturer.
About Dow Corning Construction
more than 60 years, Dow Corning has provided silicon-based,
performance-enhancing materials and additives for glazing, sealing, and
weatherproofing new and existing construction projects. For more information,