A method for connecting insulation panels, each of the panels comprising a cellulosic web having two sides and an outside edge, and comprising layers of cellulosic fibers, the method comprising:



a) arranging a portion of each panel to be adjacent to the other, thereby forming an edge portion where the two webs can be connected;
b) relaxing the fibers of cellulosic material in the edge portion of each insulation panel by applying heat to the edge portion at a temperature of 150° F. to 450° F., thereby forming a relaxed fiber edge portion;
c) compressing the relaxed fiber edge portion of each insulation panel at a pressure of at least 5 psig, thereby forming a compressed panel portion having a thickness and a density; and
d) fastening the compressed panel portions together using sewing, riveting, adhesive, tape, interlacing, stamping, ply bonding or stapling thereby forming a fastened area,
wherein step (c) can be conducted at the same time or following step (b).