Roof deck structure

Claim 1

A STRUCTURAL INSULATING ROOF-DECK UNIT ADAPTED FOR ASSEMBLY WITH LIKE UNITS, SAID UNIT COMPRISING A LAMINATED PANEL OF UNIFORM THICKNESS, A FIRST LAMINA AT ONE FACE BEING FIBROUS INSULATING BOARD ADAPTED FOR USE AS THE INTERIOR OF THE ROOF, AN INTERNAL MOISTURE VAPOR BARRIER IN LAMINA FORM INWARDLY FROM SAID FIRST LAMINA, SAID BARRIER LAMINA PROVIDING RESISTANCE TO THE TRANSMISSION OF MOISTURE VAPOR THROUGH THE UNIT, AT LEAST ONE LAMINA INWARDLY FROM BOTH SAID FIRST LAMINA AND SAID BARRIER LAMINA BEING FIBROUS INSULATING BOARD, SAID UNIT BEING RECTANGULAR AND HAVING TWO OPPOSITE SIDES FORMED RESPECTIVELY WITH COMPLEMENTARY PORTIONS FOR OVERLAPPING AT A JOINT BETWEEN THE UNIT AND A LIKE UNIT IN AN ASSEMBLY OF SUCH UNITS, SAID PORTIONS BEING EACH LOCATED AT A REGION INWARDLY FROM BOTH SAID FIRST LAMINA AND SAID BARRIER LAMINA, ALL THE DGES OF SAID BARRIER LAYER BEING COINCIDENT WITH THE EDGES OF THE LAMINAE ADJACENT THERETO, ONE OF SAID PORTIONS PROJECTING BEYOND THE NEIGHBORING EDGE OF SAID BARRIER LAMINA, SAID OVERLAPPING PORTIONS BEING SUCH THAT IN A SAID JOINT BETWEEN TWO SUCH UNITS THE OPENING OF THE JOINT MAY EXPAND AND CONTRACT AS A RESULT OF THE DIMENSIONAL INSTABILITY OF SAID FIBROUS INSULATING BOARD, SAID UNIT HAVING ADDITIONAL VAPOR BARRIER MEANS CARRIED BY THE UNIT IN THE CORNER SPACE BELOW SAID PROJECTING PORTION AND ALONG THAT PORTION OF THE EDGE FACE OF THE UNIT BETWEEN SAID PROJECTING PORTION AND SAID FACE OF THE UNIT, SAID ADDITIONAL BARRIER MEANS BEING A FOLDED TAPE PROVIDING RESISTANCE TO THE TRANSMISSION OF MOISTURE VAPOR THROUGH IT, A FIRST ONE OF TWO EXTREME LEAVES OF THE FOLDED TAPE BEING SECURED ACROSS THE EDGE OF SAID BARRIER LAMINA AND TO THE EDGE FACES OF THE LAMINAE ADJACENT SAID BARRIER LAMINA, AND THE OTHER EXTREME LEAF BEING MOVABLE TOWARD AND AWAY FROM SAID FIRST LEAF AND BEING PROVIDED ON ITS OUTER FACE WITH PRESSURE-SENSITIVE ADHESIVE.