Confidence: It's likely to be this, but I can't be certain.
Notes: The photograph isn't sharp (always difficult with crustose lichens) but the rather diffuse, greyish lichen is almost certainly Aspicilia contorta subsp. contorta, while the whiter patches may well be Aspicilia contorta subsp. hoffmaniana. Both are common on urban concrete. The very dark brown lichen is most likely Verrucaria nigrescens, but again, critical features cannot be made out in the photograph. Hours of fun to be had with one concrete wall ... Alan
See (e.g.) http://www.lichens.lastdragon.org/Aspicilia_contorta_hoffmanniana.html