EPDM Adhesives, What's The Difference?

When it comes to understanding the difference between the EPDM adhesives available, it is important to first understand the different factors involved in an EPDM installation, and how they play into the integrity of the EPDM roofing system.

With EPDM being a glue-on solution, as opposed to less versatile torched-on alternatives like felt, high-quality adhesives that meet the project requirements are a must. EPDM is incredibly resilient and has strong durability against adverse weather conditions, so using the correct adhesive is imperative - this ensures that the EPDM remains bonded to the substrate for its 20+ year lifespan and doesn’t run the risk of lifting, or flapping.

Water-Based EPDM Adhesives

Water-based adhesives are the most common choice for bonding rubber membranes to roofing substrates. As implied in the name, these adhesives use water as the solvent, which means that they are eco-friendly and easier to work with in most temperatures. This type of adhesive is applied to both the roofing substrate and - as an extra layer of defence against lifting -  to the underside of the EPDM membrane during installation.

Benefits of Water-Based EPDM Adhesives

• Ease of application: water-based adhesives are straightforward to work with, especially during times when a lot of coverage is needed. Applied with a roller, this reduces the amount of time needed to cover large areas of substrate and membrane. 

• Versatility: water-based EPDM adhesives are suitable for a variety of surfaces, including wood, metal and insulation boards. 

• Cost-effective: water-based EPDM adhesives are generally more affordable, and their cost per m² is much lower than using a contact adhesive over large areas.

EPDM Contact Adhesives

EPDM contact adhesives provide a much stronger and faster bond than water-based adhesives. They are solvent-based, and require the adhesive to be applied to both the substrate and the rubber membrane, then left to dry (cure) for a short time before the surfaces are pressed together. Once bonded, the adhesion is immediate and permanent. This makes EPDM contact adhesives perfect for bonding against upstands, or other elements of the roof which may shift over time.

Benefits of EPDM Contact Adhesives

• Strength of bond: EPDM contact adhesives form a strong bond, leaving little margin for error once applied, however these bonds are generally much stronger than water-based adhesives, and ensure that if the structure of the roof shifts, these bonds will remain intact.
  

• Durability: EPDM contact adhesives perform well in extreme temperatures, and hold up much better in areas with high foot traffic, or exposure to harsh weather conditions and strong winds.

• Water-Resistance: as EPDM contact adhesives are solvent-based, these adhesives are less affected by humidity and temperature, which makes them much more reliable in a variety of harsh weather conditions.

Best uses for EPDM contact adhesives

EPDM Contact adhesives have several best-use cases, where bonding may require additional strength, these best use cases include:

• Applying detail kits instead of using primer.

• Joining/Splicing EPDM membranes.

• Installing EPDM in strong winds, or harsh weather conditions.

• Installing EPDM to upstands or other roof details.

Conclusion

Choosing between EPDM water-based adhesives or EPDM contact adhesives depends heavily on the use case: to improve efficiency and cost-effectiveness, a water-based adhesive should be used for large areas requiring a lot of coverage, as the roll-on method allows for a greater area to be bonded in a shorter amount of time. However, for affixing EPDM to surfaces which may shift, or which have greater exposure to the elements, such as upstands, a contact adhesive should instead be used. 

Our range of water-based EPDM adhesives and EPDM contact adhesives are high quality and have been used in thousands of projects, both residential and commercial. As a core aspect of your installation, we pride ourselves on the efficiency and ease-of-use that our EPDM adhesives provide. 

If you are still unsure, we offer a large range of installation materials, including how-to guides and videos to help you better understand the process, giving you everything needed to undertake your project. We also offer our helpful EPDM roofing calculator, which will automatically calculate how much of each adhesive you need for your project. Plus, we offer on-site EPDM training at our High Wycombe premises, where our dedicated trainers will ensure you have all the information needed for you to make informed decisions throughout your project. 

For any additional information, feel free to call us, or drop us an email.