Apologies if its been on the forum before but this is how not to build an extension on a boundary!
http://www.dailymail.co.uk/news/art...home-neighbours-extension-causes-crumble.html
http://www.hse.gov.uk/press/2013/rnn-wm-14213.htm
http://www.dailymail.co.uk/news/art...home-neighbours-extension-causes-crumble.html
http://www.hse.gov.uk/press/2013/rnn-wm-14213.htm