Probably - from your images I can't get a clear enough close up to be certain - so if you want just run with Xanthoria. Xanthoria parietina is a 'weedy' species (it is probably not native) and your image depicts just the right kind of anthropic habitat for it.
Joe Potter Butler
2015-06-05
2015-06-05 1:08:30 PM NZST
New Zealand, Canterbury, Christchurch including Banks Peninsula, NZ-CA, NZ