Southwyck House, better known by locals as the 'Barrier Block' is a housing block on Coldharbour Lane in Brixton, which was built in the 1960s (!). It was designed not only to house people but also to block out noise from the Ringway Plan, which planned to plough a six-lane motorway through Brixton. Thankfully this was never built but this block was. It was designed to reflect sound back from the Motorway, hence the zig-zags.
In the end the motorway plan was killed, wealthier people in Brixton were reluctant to move in so other people moved in instead and it fell into decline just like other monstrosities.
http://www.urban75.org/brixton/features/barrier.html - about the block
http://www.cbrd.co.uk/histories/ringways/ringway1/south.shtml - about the motorway plan