We spent over seven hours resealing the roof vent/escape hatch on our Scamp
. It was slow work but we're really proud of the results. This was one of the toughest jobs we've undertaken and it was definitely a two person job.
We started removing the old hatch by removing all the screws inside and out and scraping the old caulk and sealant. There was some kind of stuff up there that was really firm, almost hard, and took a long time to scrap it off, careful not the scar the fiberglass too much.
Then we cleaned with the residue with alcohol to ensure a good seal. We picked up some aluminum bar stock, 1" X 1/8", from Lowes and used the vent flange as a template to mark the holes to drill to match up the existing mounting holes through the roof fiberglass. The goal was to use the holes that were already there and not make any new holes. (First, do no harm.)
We used stainless steel bolts with nylock nuts to bolts through the bar stock on top of the vent flange and the butyl seal, through the fiberglass into the inside, through a second piece of bar stock inside the camper.
The installation went slow and careful but all the holes lined up and all the nuts just barely reached the bolt pushed through from outside the camper. We snugged the nuts down slowly, alternating around the flange to pulled the vent cover down in the most uniform pattern possible for 24 different bolts.
I am very pleased with the results. We haven't checked it for leaks
, but we can see the excess butyl squeezed from both the outside and the inside of the flange so I am extremely optimistic for a good seal. There is still an area on the outside the camper where we may want to squirt some acrylic caulk to fill in a trough of open space where water may pool, but I don't think it'll leak, in any case. This was a lot like resealing a window, only on the roof.