absolutsnwbrdr wrote:I think you've been playing too much Tetris!
It's just the way my mind works. Fit shapes together to make it work.
absolutsnwbrdr wrote:Your idea could definitely work... I'll have to keep this in mind when I'm looking for something to do one weekend this winter! Thanks!
My secondary method, which shims the fan up, would provide best sealing and still allow the fan to be removed if it has to be serviced. If you wanted, you could make that shim incorporate the trim molding and have it basically water-tight without the trim ring (other than fastener holes for the trim ring to hold the rubber roof down).
It's something you can knock out on a table saw in the matter of an hour or two since you don't have to cut any big angles, you could even make the upper trim ring out of flat stock.
Something like 3/4" of shim, with a 1/2" rabbet, will give you 1/4" to use as trim molding and give you 1/2" to have a strong upper trim ring.