The BBC’s E-cyclopedia: the words behind the headlines explains a new British use of pebbledash as a term indicating suburbia. Pebbledash people is spin doctor's shorthand for a social group.
Thought to be Tories' paradigm target voter, numbering 2.5 million in 178 target seats. Derives from “pebbledash subtopia”, one of 52 postcode categories employed by market research specialists Experian. Average household income: £25,000; likely to read Daily Mail; not very neighbourly; keen on DIY.
Pebble dash, so widely seen (and sneered at) in English suburbs, is An external plaster which has been surfaced with clean pebbles or chips thrown on to the second coat of plaster while plastic. [Penguin dictionary of building]. It can be compared with (the more respectable) rough cast, called harling in Scotland:
Originally (Tudor times) consisted of a rendering of course stuff, rendered a second time and roughened. The rough cast, that is fine shingle mixed with hot hydraulic lime, was then thrown on. Nowadays the course stuff has a different composition, usually having some cement, and often including colouring matter (red iron oxide, yellow ochre, crimson lake) but always with pebbles or chips.