In construction, the long-term performance of sealants is an essential element to the durability of your projects.
Buildings have to be able to withstand the elements, year after year. Specifying the right materials is essential – and that includes the sealants.
With so many solutions on the market, and so many different chemistries to choose from, knowing which one to use can be difficult. So how do you choose solutions that will last the test of time?
In 1983 we started a 30 year test to evaluate the long-term durability of a variety of sealant types, and to ascertain which performs best.
Here’s what happened!
The 30 Year Test
The test was set up to include a range of real world scenarios.
As part of this process, we applied a range of different sealants to glass and painted aluminium panels. We then monitored them for the next three decades for various performance criteria such as appearance, flexibility, hardness and adhesion.
The test site was located in Miami, Florida, at exposure fields operated by the Atlas Weathering Service group – South Florida Test Service (SFTS).
This was an excellent climate to run the test in, as it’s a rural area with a climate that provides all the challenges sealants are expected to withstand - such as high levels of ultraviolet radiation, humidity and temperature in a subtropical environment.
Setting Up The Sealants
The test assembly consisted of a series of 12 by 12 inch pieces of glass and painted aluminium set in aluminium channels fastened to create a supporting frame.
Each test assembly consisted of three glass or painted aluminium panels with two horizontal in-plane joints. Both joints of each test assembly were filled with the seam sealant and then mounted to the outdoor exposure racks at the test site. It is worth noting that no primers were used in the study.
The sealants used were commercially available products sold in 1983 and marketed for use in construction applications, and were a mixture of silicone and alternative chemistries.
To determine ODR (Overall Durability Ranking) only performance characteristics were evaluated, in which visual appearance and superficial surface conditions were not included.
The five properties deemed necessary and tested for a product to be capable of withstanding long-term outdoor weathering for use in building construction applications were:
- Adhesion (ability to maintain long-term adhesive bonding)
- Flexibility (capacity to being easily bent, without breaking or cracking)
- Resilience (defined at the % recovery to the original shape within 5 minutes of being bent 180 degrees then released)
- Hardness change
Results and Observations
After 30 years, there was a clear winner – silicone!
Silicone sealants ranked higher than alternative chemistries for most of the above criteria.
Silicone sealants ranked higher than polyurethane and acrylic terpolymer sealants in durability to weathering at this test site location and performed best of all for flexibility and toughness.
With one exception, the silicone showed the least % change in hardness – proving itself as a versatile material that is advantageous over other choices.
The test showed that they were frequently stronger, more flexible and more resistant to extreme weathers – making them the obvious choice for most construction projects that need to perform and last well into the future.
Read the full test document here
Global Industry Leaders in Silicone for Building
The GE Silicones brand is a global industry leader in silicone for building. We offer a range of solutions for the whole building envelope, comprising high quality sealants and coatings that are extending the life and enhancing the performance of all kinds of buildings, all over the world.
Since pioneering silicone technology in the 1930s, we’ve maintained our position at the forefront of the industry – and have been trusted across the world's construction industry for new construction and restoration projects alike for more than half a century.
For additional information about any of our silicone sealants and coatings, or to order, please get in touch today.