Roof deck structure having a continuous vapor barrier and composite insulating element therefor

Claim 1

AN INSULATING ROOF DECK STRUCTURE COMPOSED OF INSULATING UNITS, THE INSULATING UNITS COMPRISING A PAIR OF SUPERPOSED FIBROUS INSULATING BOARDS HAVING A FILM OF VAPOR IMPERVIOUS MATERIAL COEXTENSIVE WITH AND SANDWICHED BETWEEN THE ENTIRE FACE TO FACE SURFACES OF THE SUPERPOSED FIBROUS BOARDS, ADJOINING UNITS OF THE ROOF DECK STRUCTURE JOINED BY TONGUE AND GROOVE JOINTS ON THE OPPOSITE SIDES OF THE UNITS RESPECTIVELY WITH THE FILM OF VAPOR IMPERVIOUS MATERIAL TERMINATING IN FILM EDGES AT EDGES OF THE UNITS WITHIN THE TONGUE AND GROOVE JOINTS, THE TONGUES OF THE INSULATING UNITS HAVING HORIZONTAL, PARALLEL, OPPOSITE UPPER AND LOWER FACES, THE GROOVES OF THE INSULATING UNITS HAVING A HORIZONTAL LOWER FACE FLUSH WITH THE LOWER FACE OF THE TONGUE AND AN UPPER FACE INCLINED UPWARDLY AND OUTWARDLY OF THE UNIT, SAID GROOVES BEING OF LESSER WIDTH IN THE REGION ADJACENT THE GROOVE BOTTOM THAN THE NORMAL WIDTH OF SAID TONGUES WITH THE FORWARD EDGE OF THE UPPER SURFACE OF THE TONGUES FIRMLY IMPRESSED AGAINST THE INCLINED UPPER SURFACE OF THE GROOVES, A STRIP OF VAPOR IMPERVIOUS MATERIAL COMPRESSED LOWER FORWARD ENDS OF THE TONGUES AND THE LOWER BOTTOM CORNER OF THE GROOVES AND COVERING THE ENTIRETY OF EACH OF THE FILM EDGES OF ADJOINING UNITS WITHIN THE JOINTS, SAID STRIP OF VAPOR IMPERVIOUS MATERIAL RUNNING THE FULL LENGTH OF THE GROOVES AND TERMINATING AT THE ENDS THEREOF IN CONTACT WITH SIMILARLY DISPOSED STRIPS IN THE GROOVES OF ADJOINING UNITS FORMING A CONTINUOUS AND SEALED BARRIER BETWEEN ADJOINING UNITS AGAINST PASSAGE OF VAPOR FROM ONE SIDE OF THE BARRIER TO THE OTHER SIDE, AND A VENT CHANNEL OF LESSER WIDTH THAN THAT OF THE GROOVES AND EXTENDING THE LENGTH THEREOF IN THE GROOVE BOTTOMS OF EACH INSULATING UNIT AND SPACED ABOVE THE VAPOR IMPERVIOUS FILM EDGE THEREIN, SAID VENT CHANNEL COMMUNICATING WITH SIMILAR VENT CHANNELS IN ADJOINING UNITS TO VENT DESTRUCTIVE PRESSURES BUILT UP WITHIN THE JOINED UNITS.