PVC panels above bay windows leaking moss-like substance

[fredlike]

Hi

Above my bay window frames are PVC panels. They're about 3" / 7.5 cm high.

The caulking between them and the frame has yellowed and moulded, and has come away during cleaning in some cases, some of them bow outwards in the middle a bit, and whatever was behind them has disintegrated and is falling out onto the sill in little bits of dark grey stuff (I dont' know what else to call it, don't know what it's made of! looks a bit like dried out moss).

Questions:

* What's the trade term for these panels and what's their function? Just to cover whatever handiwork and/or bodging is underneath?
* What is the substance behind them that seems to have distintegrated and is falling out?
* Would it be easy to pull them off to clean / replace the crap underneath and successfully replace them again?
* In case I mess that up can I get replacements?

Thanks for any help with this

 

[crank39]

Pictures needed to answer all those questions

 

[fredlike]

Pictures needed to answer all those questions

Here's a photo of part of one of the panels:

Untitled

• fredlike
• 19 Dec 2014
• 1

and part of this morning's harvest of the soft material that fell from it:

Untitled

• fredlike
• 19 Dec 2014
• 1

This lump doesn't look much like moss, but it's the same stuff as before. It's maybe 2 x 3 mm in diameter at most. I guess it's something like foam rubber that is crumbling?