Laying your EPDM around obstacles & angles

Step 1: To make your installation simple, do not fit the skylight kerbs until the EPDM membrane has been fitted. 

Instead, first fit some temporary boarding in your skylight openings (safe to walk on), flush with the main deck.

Step 2: You can then bond your EPDM in one piece as seen in Laying Your EPDM, taking care to not glue to the temporarily boarded area, or the area where the kerbs will secure to.

Once bonded, cut your EPDM as shown (right), by cutting from each corner towards the corner at a 45 degree angle, folding back ready to install your skylight kerbs.

You can now remove your temporary boarding. A seamless install with no seam joints!

Step 1: Fold your EPDM back as you usually would, then adhere it to your deck with your water based deck adhesive, right up to your skylight kerb (or any roof protrusion). 

To make sure the EPDM is positioned correctly before bonding, you may need to measure your folded back section, & double check it will reach the roof perimeter with the required overhang.

Step 2: Mark out the skylight size on your folded back EPDM, with the correct length & width. Chalk straight lines from one corner to the other, making an X. 

Also mark from one of the two furthest corners (see image), in a straight line to the edge of your EPDM, as shown on the picture (right).

Then cut these lines.

Step 3: Now your EPDM is cut, you can fold it appropriately so that it can be wrapped around your skylight when ready to bond.

You can then bond the remaining EPDM to your decking, leaving the triangular cuts to bond up your skylight kerb (or any roof protrusion) as seen in Bonding Your EPDM to Walls & Verticals

Step 4: As you now have a cut in your EPDM, you will need to join this together once your EPDM is bonded to your deck.

You can't use you 3'' Seam Tape here, as there isn't any excess EPDM to overlap itself.

Instead, you must 5'' Flashing Tape. 

Use a straight edge & your chalk/crayon to mark a neat line, 75mm either side of your cut in the EPDM.

Note: You will flash the corner of your skylight where your cut begins from separately & after this stage.

Step 5: Using your Quickscrub Pad & Handle, apply an even layer of Quickprimer Plus, leaving no pooling.

Once touch dry, starting at one end, carefully mate your 5 inch Flashing Tape, peeling the tape as you go, as smoothing with your other hand.

Take care not to have air pockets. You can help this by keeping the flashing taut whilst applying but not stretching.

Step 1: As before bond your EPDM all the way up to the pipe or protrusion.

Mark the area to be cut, as well as a line from the furthest edge, to the end of your EPDM.

Proceed to cut.

Step 2: Bond your EPDM around the protrusion as previously described & bond with your 5 inch Flashing Tape, also as previously mentioned.

You can also apply a continuous neat bead of Firestone Elevate Lap Sealant on all flashing edges to improve the seal, taking care to not have your bead too proud, creating a lip stopping water run-off.

See EPDM Pipe Sealing for tips on sealing around pipework.

Step 1: Bond your EPDM as previously outline, all the way up to the point where EPDM will then need to continue around the corner.

Then cut your EPDM from the corner, at a 45 degree angle back towards yourself.

You can then continue to Bond the EPDM to the remaining L-shape, & seal your External Corner if applicable.