http://www.youtube.com/watch?v=Mrjg0wjdh2Q&feature=plcp Commercial and residential specifiers are faced with an ever-widening  range of materials to select from for external surfaces.  From concrete  to clay and asphalt to resin bound paving, the choice to the  uninitiated can be bewildering, with manufacturers keen to promote the  specific benefits of their own product ranges. Increasingly…