Roof/alcove skin question

[Darkyputz]

Hello...

I hope this is the right category to ask these things in,so please correct/move me when needed.
But now to my question...
Our 2001 coachman is in some distress...
Some delam here and there and the epdm roof is at the brink of existance but so far still water tight.
Now i am planning to overhaul the issues and was wondering a thing...
Why is the roof epdm liner o ly up to above the driver seat and than pvc around the front nose.
What w/c/should stop me to take the pvc of the nose and just put a fresh new epdm liner from the back all the way around the hole front nose to have one non interrupted roof surface?
I would litterally like start from the backside bottom behind the bumper and run it complete over whole roof and nose.
Curious about ides, statements and intel you hopefully can provide

Thx in advance

[MrMark52]

Watching.

[Tim Adam]

PVC can be a difficult material to try to bond membranes to and would need some pretty extensive prep work and a suitable adhesive. Also the way that the front is molded may be difficult to effectively lay a EPDM membrane over without it folding or creasing.