Roof trim help

Maybe try some very strong 3M double sided tape rated for outdoors.

 

I'm not sure if Prius C is different but if it's the same as the long inch wide black strips on roof of Gen2, there's some clips that hold it in place and by bending those clips a little, that should hold it all down.

 

Maybe it would be easier to just replace the strips? There's a bunch of companies that provide aftermarket auto trim in every possible dimension and you could possibly order something that's not only inexpensive, but doesn't come loose due to shrinkage over time.

And if you do find something that works better, I'm sure there's lots of Prius C owners on here that will want to know about it.

 

After replacing both sides for the same problem, the strips once again started popping out while going thru car washes about a year later. But I have seemed to found a fix.

I found a can of this on the shelf at my parents house.

Permatex by dubit posted Jan 27, 2020 at 5:33 AM

Yes, it's brush on gasket seal. Extremely tacky, but easy to work with. I removed a strip, placed it on the garage floor upside down and brushed in this gasket seal. Then, with the help of my brother holding one end, we re-installed the strip. So far it's held in place for a little over a year now.

This "high tack" gasket sealant can be found at any auto parts store and even Wal-Mart for under $10.

 

I just removed mine since they serve no purpose.