Sorry for the awful picture quality, it's hard to get a clear photo from ground level.
Basically for the last few months I have noticed there are 2 "things" on my roof (highlighted in picture), I initially assumed it was something a bird had dropped there but since they haven't moved in months I'm now guessing this isn't the case. I know it'll probably be impossible to tell what these things are from the photo but thought I'd check just in case anybody recognises what these are?
Also, more generally, what type of roof is this? I expect they have a limited life (I believe current roof is about 40 yrs old) but what actually happens when they reach the end of their life? Do they need fully replaced or generally speaking can they be repaired in an ongoing process to stretch the life out?
Thanks