The Growth of EPDM Roofing
First introduced in 1962, EPDM single-ply roofing membranes ended up being significantly popular in the 1970s as the Middle East oil embargo increased the cost of asphalt-based roofings and decreased the quality of available asphalt. EPDM was cost-efficient and basic to set up, and quickly became known for its remarkable hail resistance, UV stability, and weathering resistance due to the cross-linked nature of its chemistry and the UV-absorbing power of its raw materials..
Given that its introduction, numerous improvements have been made to the system parts, making today’s EPDM systems much more robust and a higher value than ever before. There are 4 primary areas in which significant improvements have actually been made to EPDM system technology, improving performance and increasing value for the building owner.
Improvements to Seams.
The first location of improvement was in EPDM seaming technology. In the 1970s, EPDM seams were created utilizing white gas and a Neoprene-based splicing adhesive. Nevertheless, the Neoprene polymer in the splice cement could break down and lose strength with extended direct exposure to ponded water. While most systems are created to promote favorable drain, it’s rather typical to have little locations of ponded water on the roofing system for extended amount of times..
In the mid-1980s, a butyl-based splice adhesive was developed to be used in lieu of white gas to clean up the joint area. Butyl-based adhesives were used in pond liner applications and are really tolerant of ponded water. Nevertheless, the seaming procedure still included many actions, leaving joints prone to variations brought on by craftsmanship strategies and installation conditions.
It wasn’t for another 20 years that customized guides and double-sided seam tape emerged. These products dramatically streamlined the seaming procedure and reduced craftsmanship inconsistencies. The more variability taken out of a process, the more constant the results.
Around 2005, seaming elevated to the next level with EPDM sheets and Factory-Applied tape, in which splice guide and splice tape are pre-applied to one side of the sheet in a factory-controlled environment. This breakthrough in innovation even more reduced craftsmanship problems and improved the quality of completed splices, due to the fact that professionals simply needed to roller-apply guide to one side of the sheet and after that mate the two sheets together with a seam roller..
Factory-Applied tape not just enhanced seaming efficiency by 65 percent, it likewise improved seam quality so significantly that Carlisle Syntec saw an 80 percent drop in seam-related guarantee claims. Today, professionals are reporting less call-backs for craftsmanship concerns on EPDM joints than heat-welded seams.
Improvements to Angle Change Securement.
The approaches for angle modification securement of EPDM membranes have actually also enhanced considerably. In the early days, wood nailing strips were utilized to hold the membrane in place at a 90-degree angle at the base of parapet walls. In ballasted roofs, which were the most popular style back in the 1970s, the EPDM membrane is loose-laid, leaving it free to move. All roof membranes diminish somewhat as they age, and in a ballasted system, the shrinkage force is transmitted to the perimeter securement. Wood nailing strips carried out well when brand-new, however over time, they would dry-rot and pull out over the fastener heads, triggering the membrane to “bridge” away from the wall.
Wood nailers were replaced with extruded rubber/plastic nailing strips that enhanced the weatherability of the nailer itself, but they still didn’t have sufficient fastener pull-through strength for some big ballasted tasks, and bridging stayed a concern.
In 1989, Carlisle presented the RUSS (Reinforcing Universal Securement Strip) information, where a 6″ large reinforced EPDM membrane is held in location by fasteners and 2″ metal seam fastening plates. EPDM field membrane is then entwined onto the RUSS with the same shear-resistant items used for seaming. It took three years of strong marketing and education to convince contractors to alter to this innovative new information, however it’s carried out extraordinarily well over the past 27 years and is still used today.
Improvements to Puncture Resistance.
EPDM’s leak resistance has considerably increased because its introduction. For many years, 45-mil non-reinforced EPDM membrane reigned supreme with dominant market share, especially in ballasted systems. More recently, the market has actually moved significantly towards 60-mil membranes. A 45-mil non-reinforced EPDM was economical and offered outstanding weathering efficiency. However, it didn’t use as much puncture resistance as the thicker 60-mil non-reinforced EPDM..
Producers presented a strengthened EPDM sheet which contained an internal scrim for included toughness and toughness in the mid-1980s. On a 60-mil membrane, including strengthening scrim to the sheet increases leak resistance by around 50 percent. One compromise with internally reinforced membranes of any type is that they include less weathering material over the scrim. For instance, on a 60-mil enhanced sheet, the density over scrim varieties from 20 to 25 mils..
An externally reinforced sheet, fleece-backed EPDM, was presented in 1996 and featured the greatest puncture resistance of all the EPDM membranes. For a 60-mil membrane, adding external fleece reinforcement increases leak resistance by around 300 percent. Since the sheet is externally strengthened, fleece-backed membranes include a complete 60 mils of weathering material above the support.
Now professionals have the option of a 90-mil EPDM, which has two times the puncture resistance of the initial 45-mil rubber and includes the most weathering product of any single-ply membrane on the marketplace.
Improvements to Flashing Details.
Flashing details for EPDM roofing systems have enhanced a lot over the past 50 years, and these enhancements have considerably boosted the overall quality and performance of EPDM roofings. From 1962 to the 1980s, wall and penetration flashings were manufactured from uncured Neoprene. This material formed and spliced effectively, but its UV resistance was less than that of the EPDM membrane. In time, Neoprene flashing would crack and trend, and became one of the prime modes of failure..
Flashing made from uncured EPDM was introduced in the mid-1980s. Uncured EPDM flashing provided drastically improved weathering homes and none of the surface splitting problems. A line of premade pressure-sensitive inside/outside corners, pipe boots, and pourable sealant pockets for EPDM systems was then established. These items quickly got popularity because they streamlined the application process and improved the quality of the completed roof. Today’s pressure-sensitive flashings feature a complete 60-mil EPDM weathering layer laminated to 30-mil treated adhesive for a 90-mil total thickness. This included density contributes to the sturdiness and toughness of EPDM flashings.
In 1992, wall and curb flashing details were updated to need treated (instead of uncured) EPDM membrane for included toughness, resilience, UV resistance, and weatherability. This was a natural development with the intro of the RUSS detail that enabled the high-performance EPDM field membrane to run constantly into the angle change and up the wall.
EPDM: Time-Tested and Built to Last.
In summary, today’s EPDM systems are reliable and developed to last, which is quite in sync with the growing emphasis on sustainable building. EPDM has actually made a terrific reputation for weatherability, hail resistance and long-term value from over 50 years of real life performance. Technological advancements such as seam tapes, guides, RUSS angle change securement, puncture resistant membrane alternatives, and more robust flashing details have actually made EPDM the system of choice for numerous architects, professionals and building owners.
NRCCA is another great resource for information on EPDM roofing materials.