Silicone or butyl tape for weather-proofing bed?

I'm prepping my truck to put a shell on the back. After searching around here, I feel I have a handle on tailgate seal, sealing the bed cubbies, and plugging the front corners.

But I was curious what folks used for sealing underneath the bed rail covers and under the header rail. The 2 two options I've seen discussed for those places are marine silicone and butyl tape.

If you've sealed yours, which did you choose and why?
Did you use aluminum tape as well?

 

Butyl all the way!

 

I did the same before I installed my Softopper. I cleaned and touched up the paint. There were some wear spot and I only had a tonneau on there.

I then laid down some thick foil tape and silicone on top of that. About the only thing that I would do different is go heavier than the beads that I used.

 

Butyl! it never shrinks and is water tight

 

I did both. Butyl for the bigger gaps and silicone for the small stuff. Pull off your plastic bed caps and bed rails, run some silicone under those and re-install.

 

Thanks for the post showing.

 

You're welcome!

 

Can you share what you did for the tailgate seal? The things I have tried have worked but only temporarily. Any adhesive backed foam or silicone seal/gasket hasn't stayed stuck

 

Also, I got ahold of a buddy that lives on a sailboat. He said that after the first few years of messing with silicone, he's transitioned to butyl tape for everything above the waterline. He strongly recommended Bed-It brand as better than any other butyl tape he's encountered. So I think I'll use that for all the places I was still considering silicone.

https://shop.marinehowto.com/products/bed-it-tape

He's currently sailing from Mexico to Hawaii, so his endorsement that the stuff holds up to real ocean travel is good enough for me. Hope it's helpful for other folks.

 

An adhesive backed foam is what I just got for that in the mail. Will report back with how it holds up, but don't have any better suggestions.

 

Remains flexible for decades too without separating or drying...

 

I went with 2 parallel strips of butyl around the perimeter of mine. It still leaks in the corners which is driving me nuts. Buuuut I left the bed rail caps on and I see so many others took them off.

Is there a concern with the bed rails crushing without the caps, due to the weight? Would taking the caps off help with my leaking? Thanks!