The mystery revolved around Madison-era architectural fragments found reused in one of Montpelier's outbuildings.  Before the Restoration, all of the estate’s outbuildings were inspected to see if any Madison-era elements might have been reused in the buildings.  The Restoration Team believed that because the duPonts had reused Madison-era materials in the ca. 1901 renovation and expansion of the Mansion, that they might have also reused some of the materials in the farm’s outbuildings.  In one instance, their efforts paid off more than they could have hoped.  When they inspected the framing for the ca. 1901 wings that the duPonts had added to Montpelier's ca. 1881 bowling alley, they discovered that the joists used to support the floors in the wings were actually reused rafters that had once framed the roofs over Montpelier's ca. 1812 wings.