Insulation body

An insulation panel having a back face and a front face, the back and front faces being spaced apart and being generally parallel to each other, the panel including a female edge having a recessed region along its length, the panel further including a male edge located at the opposite side of the panel to the female edge and which has a male shape which is complementary to the recessed region of the female edge so as to closely fit within the female edge of an adjacent similar insulation panel, the front face having two integral webs located at and extending respectively along the female and male edges of the panel, each web extending across substantially the entire distance separating the back and front faces so as to define a cavity within the panel, the cavity having a base wall defined by the front face and two opposed side walls defined by the webs at the female and male edges of the panel so that the cavity can receive and retain an insulating material filling for the panel, the web at the female edge of te panel being shaped so as to define the recessed region, the recessed region of the female edge being generally channel shaped, the channel shape being defined by a front wall, a back wall and a base wall, the front wall of the channel shape comprising an edge portion of the front face which is turned inwardly towards the back face and then turned back upon itself to define a double thickness front wall of the channel shape, the edge portion of the front face being further turned to extend towards the back face so as to define the web and form the base wall of the channel shape, the web at the male edge of the panel being shaped so as to define the male shape which fits within the channel shape of the female edge, the male edge being generally channel shaped and having front and back walls and a male edge base wall extending across the distance between the front and back walls of the male edge channel shape, the front and back walls of the male edge channel shape defining a channel shape having a width to fit within the female edge channel shape, each web having an edge portion remote from the front face and which turns outwardly of the general plane of the web to form the respective back walls of the female edge channel shape and male edge channel shape, the back face of the panel being provided with edge portions which are turned in and towards the front face and then turned back on themselves to receive therein the edge portions of the webs, the edge portions of the webs and the edge portions of the back face being secured together.