So, other than what's between the in and the out of a pop top, I was curious how to fill in the ribbed outer roof and make it weathertight. I didn't want to use wood, no matter how smothered, covered or gooped it was. I figured nothing would bond to fiberglass like fiberglass.
Prepare area by grinding off newly installed Rhino Liner (more on that in another thread)
Make 3 trips up and down the ladder gathering what it takes to actually mix and apply fiberglass. Don't forget to admire your own Raptor Liner handiwork. Raptor Liner is awesome. It should come factory on all PH tops. That is all.
Lay lots of resin in the channels, it took me two applications. Don't get in a hurry. You can see some added 1/4 strips in the 'sandwich' in this pic to give the roof vent screws more to bite into, without risking going through your interior ceiling.
Sand down and start feathering and cleaning
Lay a thick bead of butyl tape
Go back down the ladder at least once and take a pic of what you've done inside, scratch head over weather you've totally screwed up the layout of proposed interior.
Drink a beer if successful, coffee if not.
Don't forget to wire it up! A roof vent needs to be on constant power of course, and doesn't use a lot of it. Make sure you have an accessible fuse somewhere.
Inside shot of finished product, including new ceiling and upholstered boxes, and new Thinlites! More on all that in another thread too.
Spacing of 3 piece bed cushions for use with top down, 2 forward and one behind in my case, with just enough room to access the forward PH latches
I forgot to mention this obvious step, but after you screw the fan down add a thick layer of polyurethane sealant around it and over all screw holes. I used this stuff I recently got for a stove pipe install that will stick to anything. It's clear and awesome and that's all I know about it. I'm sure I threw the empty tube away without noting the name, but there's lots of similar stuff out there. What I used was sold to me by a metal roofing supply house and it's what they use on all of their roof/chimney/gutter installs. I trust it.
Other note: NO reinforcement is needed on a RB penthouse in my opinion. There is plenty of support close by with the X-frame cross members. I can stand right on either side of this vent and the roof barely flexes.