What adhesive to use with EPDM rubber sheet roofing (shed project)
Forget about it. EPDM is too picky.
EPDM is a complex roofing product that requires a variety of fairly specialized chemicals to work together.
I have a feeling you got all excited when you saw the square foot price for just the rubber membrane. Then you researched and priced the approved glues and other kit... and found out that would quadruple the price!  And that makes rubber more expensive than shingle, and more like the cost of high performance roofs like metal.  Yeah, it's like that.  But it is a high-performance roof, if you can keep the &quot;stupid&quot; away.
&quot;Stupid&quot; is any misuse of another chemical. Tar is the #1 enemy of rubber roofs, and many roof &quot;products&quot; are actually made of tar even though they really work hard to dodge admitting that.
Our poor nonprofit had a new $12,000 rubber roof - should've been a 30 year roof, a welcome respite to 2 decades of roof problems.  Except one genius thought the black roof made the building too warm, and painted it silver.  With cheapie RV roof coating (you know, the $90 for 5 gallons stuff which is tar). Utterly destroyed the roof.  The rubber became brittle and parted from the (expensive) glue holding it to the OSB, started moving around, cracked, and leaked.  Voided the warranty of course.  Patching it is hopeless, more tar only makes it even worse, and proper rubber patches won't stick to the silver/tar topcoat.