What causes brown window frames to lose their film covering?

[Gary111]

Hi, Is it just due to age that these windows are looking like this?
I notice the patterns are different side to side.
Thanks

 

[Gary111]

 

[robinbanks]

Tempted to say in that particular case something has attacked the adhesive holding it on encouraging it to let go, or dissolve. Perhaps the frame was too big so was shaved down a bit, exposing the edge of the glue, and something has since affected it such as the solvent in the mastic, moisture from somewhere erc

Also judging by the way it's rippled the window looks to have settled downwards a little but the loosened wrap has remained adhered to the brickwork via the mastic, so it's pulled it into that odd angled pattern.

As for what to do about it; nothing, or overclad it with a bit of brown trim if it bothers you. I think you run the risk of making it much worse if you try anything drastic.

 

[Gary111]

Tempted to say in that particular case something has attacked the adhesive holding it on encouraging it to let go, or dissolve. Perhaps the frame was too big so was shaved down a bit, exposing the edge of the glue, and something has since affected it such as the solvent in the mastic, moisture from somewhere erc

Also judging by the way it's rippled the window looks to have settled downwards a little but the loosened wrap has remained adhered to the brickwork via the mastic, so it's pulled it into that odd angled pattern.

As for what to do about it; nothing, or overclad it with a bit of brown trim if it bothers you. I think you run the risk of making it much worse if you try anything drastic.

Thanks for your detailed answer mate.