according to the info i read on the back of my can of undercoating, it only takes 10 minutes. I'd give it a 1/2 hr myself.
Short answer, NO you do not NEED undercoating.
It will depend on how much undercoating you are wanting to rubberize.
how long does roof cement to dry
No.
how long does it take for bituman to dry outside
is a scinentific method
An hour
40 days
you will never know
Yes it does.
well im thinking it will take 5 houres for water to dry on asphalt.
How long does it take to heal a butterfly wing