Leaking Upper Helm Aluminum Top

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Veteran Member
Jun 4, 2021
My upper helm and aft doghouse cover is fabricated of welded square aluminum tubing with pop riveted aluminum sheeting, covering the frame. It is strong and can be walked upon without issue.

While installing insulation enclosed by pvc bead board to the underside of the aft doghouse cover, I discovered small amounts of water seeping through the top's sheet aluminum metal joints. (note: there are two aluminum sheets covering the entire top, with one butt joint in the middle, over one of the square structural frames, attached by pop rivets.) There is also an unsealed joint on all sides, between the sheet aluminum top and the square aluminum frame that supports it, again attached by pop rivets.

In the past I noticed a drip of water coming through a pop-rivet, so I sealed all of the pop rivets with caulking.

I need to seal the top, as, I am worried about water penetration into the enclosed area between the sheet metal top and the beadboard and mold formation.

I am also concerned about capillary action between the edge of the top sheet metal and the square frame, at the sides and back of the doghouse cover.

The aluminum top was properly coated with Interlux aluminum epoxy primer and paint at the time of fabrication, and the coating appears to be in good condition.

I've thought about using one of the self-leveling caulks, successfully used on motorhomes, to seal the sheet metal butt joint. I am also considering using epoxy on the joints. Then, maybe I should just clean up the whole top, rough the surface and paint with a rubberized roof paint. I have also considered asking a welder to weld all of the sheet aluminum joints. Mabe the welder could even spot weld all of the pop rivets???

Final complication, a lot of sealers/caulks don't work very well of aluminum.

I use this top from time to time as access to the top of the upper helm, so the ability to walk upon it is important.

Any thoughts are appreciated.
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