Roof screws question

[Mderou]

Hi all,

I've read a lot here about the roof screws and see that many are using a 3M 4200 sealant. Curious why one wouldn't just dollop the top of the screw with Dicor lap sealant? Or if doing both makes sense? I have a lot of Proflex sealant laying around and was thinking about applying that to the threads of the screw and then Dicor over it to be used as a "flashing". A concern there is if the Proflex seeps out from under the washer a little, I don't know how well Dicor would adhere to it. It seems like overkill, but when you live in the PNW preventative measures are important. But then again, the factory installed the screws with no sealant to speak of and water hasn't intruded. Also, to complicate things further i read something about spraying insulation foam into the rears screw holes, but couldn't quite conceptualize the why? If anyone has insight, would love to hear it.
Thank you.

 

[Edgewood]

I did exactly that. No leaks in three years!

 

[Mderou]

I did exactly that. No leaks in three years!

Did you wait for the profex to cure before applying the Dicor over, or just all in the same session?

 

[Edgewood]

Dicor after the roof still leaked weeks later.

 

[BellaFWC]

3M 4200 sealant a month ago. I pulled the roof rack off and found a few mis-drilled holes that for sure were the leak points. Sealed up every screw under and on top of the screw on the roof while up there and no more leaks and I have been in 3-4 heavy downpours since.

 

[Beach]

Overkill to cover the screw heads but if you want go ahead, can't hurt anything. Putting some sealant in the screw hole or on the threads works well as a thread locker. Be sure to clean the roof when you pull the old screws to insure no dirt or oils are present

 

[Mderou]

Overkill to cover the screw heads but if you want go ahead, can't hurt anything. Putting some sealant in the screw hole or on the threads works well as a thread locker. Be sure to clean the roof when you pull the old screws to insure no dirt or oils are present

It turned out pretty good. Only the center line was hard to access the rest you could do with a ladder. I had a lot of extra Dicor, and in the PNW water will find a way. I'm glad I did it.