which is 20-30 feet shorter than what Trump has proposed:
$10 billion in concrete
$5-6 billion for steel columns (including labor)
$1 billion for concrete footings and foundations
$2 billion for roads to support the 20-ton trucks that would deliver the materials
Another 30% for engineering and design management
Estimating the price based on The Washington Post’s reporting, Oliver concluded it would cost $25 billion — two- to six-times Trump’s proposed price tag
http://fortune.com/2016/03/21/john-oliver-trump-wall-mexico/