EPDM is a safe an easy material to install on roofs because the system relies on glues and tape with primer for most applications. This includes the fitting of most accessories.
When fitting an EPDM rubber roof, you will need various adhesives for different applications.
As a rule, when adhering EPDM to the deck you will need Water Based Adhesive and Contact Adhesive for the perimeter. Contact Adhesive is also used to stick the EPDM to vertical surfaces and to accessories (not including tape). Tape Primer is used with all EPDM tapes to ensure they attach to both the membrane and any other surface.
EPDM Water Based Adhesive
Water Based Adhesive (WBA) is a solvent free glue. It can only be used with porous surfaces such as timber or concrete because the glue needs to be able to soak into the surface to create a strong bond.
WBA is used for the deck because:
1. It only needs to be applied to one surface (the deck) so it speeds up application.
2. It has a slower drying time so allows for some manipulation of the membrane once bonded.
3. It is more environmentally friendly due to its lack of solvents
WBA is easy to apply with a roller, directly to the roof deck. The EPDM membrane should be laid directly into the adhesive when it is wet, then broomed over to remove any air bubbles.
WBA is not good for walls and upstands because the slow drying time could mean the rubber shifts position before the glue has gone off. This is also why Contact Adhesive is used around the edge of the deck.
EPDM Contact Adhesive
Contact Adhesive is a super strong, instant grab glue. It can be used with any surface but must be applied to both faces to be bonded.
Contact Adhesive is used for the perimeter, upstands and accessories because:
1. Once tacked of, the two faces will bond instantly when mated (EPDM to wall etc).
2. There is no need to secure the EPDM to the surface while the glue is going off.
Contact Adhesive is applied with either a mini roller or a brush to both the EPDM and the surface it is to be mated to. The adhesive needs to be applied evenly, then allowed to tack off (this means that it is touch dry without any ‘strings’ of glue coming away) before bonding. The area should be rollered over to ensure good, even adhesion.
EPDM Tape Primer
EPDM Tape Primer is not an adhesive, but it is used with tapes to create a good bond between them and the EPDM or surface. Tape primer is applied using a brush, only to the surface to which the tape is to be bonded – it should not be applied directly to the tape.