Thanks Axiom. Off the hunt to find a tradesman familiar with EPDM.
For my own wiki, mind advising is it just industry wrong , etc on the Roofer A : Iso / Ice&Water shield/cement/SBS
Roofer A basically says he could lay down iso, then the shield and if it happened to rain that day, water would not even get past that.
----this was the notes I saved on the blurbs I came across re: EPDM
EPDM was originally created and intended for large warehouse roofs with a minimal amount of foot traffic and a minimal amount of cut-outs.
EPDM comes in sheets that are 10′ high X 100′ long. Unlike other roofing materials, EPDM is not adhered by glue, adhesive or tar. The reason is EPDM’s high concentration of rubber expands and contracts at a much higher rate than any adhesive glue or tar on the market. Therefore, it needs to float on the roof to prevent it from prematurely deteriorating. The glue that is used in conjunction with EPDM is only to be used on seams, cut-outs and low parapet walls. Some contractors glue all the EPDM to the roof decks, this is a great injustice to the homeowner. The reason is that the glue expands and contracts at a much lower rate than the EPDM membrane itself,
causing a conflict between the glue and the membrane and also causing a guaranteed premature deterioration of the roof system itself.
EPDM is first cut to the width of your roof. Including parapet walls. For example, if your roof measures 20’x 60′, you will have six 10×20 foot sheets of EPDM installed.
EPDM is then mechanically fastened at each 10 foot seam with a screwed down windbar and a sealing tape. The parapet walls (if any) can be glued on. All cut-outs will be sealed by glue and a special caulking adhesive. So in between each 10’x20′ sheet is a hollow non-adhered membrane with dozens of screws fastening the seams. If there is a leak (tear)on the front of an EPDM roof and the slope is going toward the back of the house, you can be in big trouble. If the tear is large enough it is possible for the water to travel underneath the whole system causing leaks in every room of the house.
Over the years, this EPDM roofing system has been nothing less than a nightmare for residential roofing when a leak occurs. And leaks could be caused by many things such as fireworks, foot traffic, cable dishes, atennas, sharp edge tools, falling branches, etc.