Harry Bloomfield wrote:
Hi,

I've never used the stuff, so I don't really know its properties.

We had new plastic guttering/fall pipes installed ome years ago.
People next door (other half of semi) have just had square section
system put in, which does not match up with ours. Our round fall
pipes have been removed and now replaced with square, without a
'would you mind if...'.

Our half round gutters obviously do not fit the square T at the top of
the fall pipe, so the installers instead of obtaining an adaptor, just
stuck it in with expanding foam.

The question is, is this adeqaute, or can we expect deterioration and
problems later? I suspect the later.

Unless they have applied some kind of coating then certainly the latter. The
stuff doesn't like exposure to the sun at all.