"Rippled" Glass

How would you go about doing - in Cycles [2.76] - rippled glass. By rippled glass I mean that odd textured glass that you sometimes find in old hospitals / schools. More a European / New England - Montreal/Quebec for Canada - thing than in more modernized cities.

You sort of have to squant, but the top half shows what I am talking about
http://st2.depositphotos.com/1801119/7692/i/450/depositphotos_76922467-Old-wall-from-square-wooden-frame-and-glass.jpg

Looks like a Noise/noisy Voronoi bump map to me.

Glass shader. Plug noise texutre into height slot of bump node. plug normal slot of bump node into normal slot of glass shader - adjust size, height parameters to suit…bobs your uncle