Fully Adhered EPDM Application
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RubberCover EPDM is fast, safe and straightforward to install, using cold, water-based and bonding adhesives. In this guide, we’ll show you how to address main area application and what to do when preparing to fit the membrane around a skylight upstand and a pipe extrusion. Easy-to-follow steps according to our in-house training team and the manufacturer guidelines.
How to handle a fully adhered EPDM application
Step 1
Once the substrate is properly prepared, the EPDM membrane should be laid out onto the roof and positioned. Make sure there is sufficient overhang in all the right places – perimeters, upstands – where it will be trimmed later.
EPDM can take around 30 minutes to relax, so leave it in situ. This allows packing creases to dissipate. If you’re left with any stubborn or deep creases, which is common if the membrane has been stored folded for a while, they may need closer attention (please see our guide – How to Remove Creases from RubberCover EPDM).
Step 2
The membrane is applied from the centre of the roof out towards the perimeter edges. At these edges and upstands, folds excess membrane back onto the roof. This ensures any wrinkles are removed, making the membrane easier to apply. Then fold the sheet back onto itself exposing approximately half of the roof substrate.
Step 3
Bonding of the membrane can now begin. Using a 9-inch roller, apply the water-based bonding adhesive to the timber substrate only. Once the adhesive is applied, the membrane can be laid into it whilst still wet. Roll the membrane into the adhesive avoiding stress or wrinkles, taking care to spot and remove any debris that may have fallen onto the deck in the meantime.
Entrapped air and wrinkles can be removed by gently smoothing with a soft bristle broom, adding more pressure with each pass of the broom. Do not stretch the sheet.
Step 4
Roll back the other half of the membrane until approximately 100mm of the already applied adhesive is visible and repeat the procedure.
Note that the water-based bonding adhesive does not go right up to the perimeter edge of the roof deck, but instead terminates 100-150mm away. This area is where the bonding adhesive will be applied later. The water-based adhesive can take up to a few hours to grab the membrane completely depending on ambient temperatures, but the use of the bonding adhesive around the perimeter edges secures the sheet in place during this period.
Important notes:
The above method of application relates to a timber deck (plywood or OSB) only. For direct application to other surfaces e.g. polyisocyanurate insulation board or concrete, bonding adhesive must be applied to BOTH this substrate and to the back of the membrane. Allow it to become tacky to a finger touch. The membrane can then be applied to the substrate. Broom the membrane surface to ensure sufficient contact of the membrane with the substrate.
Step 5 - encountering an upstand
When applying the field sheet and a chimney or skylight is encountered, the membrane needs to be applied around this protrusion. Measure the width and depth of the protrusion and transfer these dimensions onto the folded membrane. Draw an X inside the box.
Step 6
Cut a straight line from the nearest edge of the membrane to one corner, then cut the X mark lines.
Step 7
Roll the membrane around the protrusion, leaving a triangle of membrane that turns up all 4 sides. These upstands can be adhered using bonding adhesive later on.
Step 8 - encountering a pipe penetration
A pipe penetration is dealt with in a similar way. Once the membrane has been cut and laid around all obstructions, the rest of the bonding procedures can continue.
Important notes:
For fully adhered installations that are typically over 100 sq. m in area, base tie-in details are required for additional securement. This procedure requires the addition of a reinforced perimeter fastening (RPF) strip, V-plates and all-purpose fasteners to be attached at the upstand and perimeter edges. For further details, please refer to our guide - Mechanically Fixed Application.
More guides from PermaRoof UK
PermaRoof UK offers support to both trade and DIY for EPDM application. We provide a further range of installation guides, datasheets, product and technical information in the Knowledge Base and in our corporate resource library here.
Become an expert with our EPDM training days
We run accredited EPDM training days for both sheet membrane application and liquid waterproofing. Training days are held at the PermaGroup headquarters in Derby at our purpose-built, approved training centre. Intensive, one-day courses and certification.