Roofing/Replacing a Front Porch Roof on a Row Home
My row home's front porch roof is in need of repair/replacement. There doesn't appear to be any sort of divider between my roof and the neighbors' roofs on either side. They are all currently "torched" roofs with 2-4 layers of material. I have proposals from two respected roofing companies to replace my roof with EPDM. One company says the adhesive used for EPDM is incompatible with a torched roof and the other says its fine. The one who says its incompatible will essentially install a piece of metal flashing where the EPDM meets the torched roof to "marry" the two. The other company will overlap the EPDM over to each of the neighbor's roofs. Is one right and one wrong or is it a "style" thing?
Cured EPDM (rubber) and modified asphalt membranes are incompatible. If your membrane has granules it could be either APP (plastic modified) or SBS (rubber modified). If it has no granules and is black, it is APP.
So I assume you are replacing your roof and your neighbor is not. So how does one tie-in an asphalt modified membrane to an EPDM roof.
The metal tie-in is a good idea since it can be married to both membranes.
Tie the metal into your roof with the EPDM bonded to the sheet metal. If fact ask your roofer if you could use a seam tape adhered with primer to the metal, then bond the EPDM to the seam tape, just like completing a standard EPDM sidelap. Extended the primer past the outside edge of the seam tape so it will help the lap sealant adhere to the metal when you install it at the leading edge (end of the EPDM membrane on the metal)over the seam tape.
The modified membrane would have to be torch-applied to the asphalt primed other half of the sheet metal. The leading edge should be sealed with asphalt mastic
Hope this helps.