But the R-value of a cordwood masonry wall must take into consideration both the wooden portion and the insulated mortar portion as a combined system. The only authoritative testing on the R-value of cordwood masonry was conducted by Dr. Kris J. Dick (PE) and Luke Chaput during the winter of 2004-2005, based on thermal sensors placed within a 24-inch thick wall at the University of Manitoba. A paper reporting on their findings appears in "Cordwood and the Code: a building permit guide" The authors' summary says, in part: "Based on approximately three months of mid-winter temperature data, the wall was determined to have an RSI Value of 6.23 (m²K/W), R-35 for a 24-inch wall system."