{HEAD ~ The flexible sheets} have a width which is greater than the width of the insulating boards so that {TAIL ~ longitudinally extending edge portions} of the sheets project outwardly from the edges of the insulating boards 
{ HEAD ~ The flexible sheets } have a width which is greater than the width of the insulating boards so that { TAIL ~ longitudinally extending edge portions } of the sheets project outwardly from the edges of the insulating boards
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH