fantastic fan install version two

[62overlander]

In this install the time required is significantly longer that 23 minutes... I have what looks to be an after market vent that looks like it might have been produced to replace after market vents. There are #10 sheet metal screws about every 1" around the mounting flange and 7 or 8 tubes of silicon caulk on top of that. I want to be sure the fantastic fan is mounted correctly and all the holes in the skin worry me. Would it be smart to cut out a square of 2024T3 about 16" x16" and cover over the old holes? I think I would be able to seal the old screw holes this way and give the new holes virgin aluminum to bite into. What do you all think? I know not to use the gasket provided, but should I use buthayl tape or vulkum under the flange?

[lewster]

62'

If the new FF flange totally covers the old holes left by removing the old vent, then IMHO, you don't need to use an aluminum piece to cover it. When I install a roof fan, I use a liberal bedding of SikaFlex 221 under the flange, bed it into the SikaFlex, attach the flange (I use screws) and then apply a very liberal dose of Dicor self-levelling roof sealant or more Sika-Flex.

There are several methods and choices of sealants and butyl tape works also. I prefer the SikaFlex for it's bullet-proof sealing capabilities. It is one tough sealant!

Just be sure that you aren't going to want to remove or re-position this thing while you own the trailer.....'cause it ain't gonna move!