Patent ID: 7818936

Claim:
A set of panels for use in constructing a form-work for concrete, comprising: a plurality of first, second and connecting wall panels extruded longitudinally to define a constant cross section along a length of each panel, the panels each having opposed first and second longitudinal edges; the first wall panels arranged to be connected edge to edge to form a first wall; the second wall panels arranged to be connected edge to edge to form a second wall generally parallel to the first wall; the connecting wall panels arranged to span transversely between the first and second walls with a first edge of each connecting wall panel having a first connector for connection to adjacent edges of an adjacent pair of first wall panels and with a second edge of each connecting wall panel having a second connector for connection to adjacent edges of an adjacent pair of second wall panels, the connecting wall panels holding the first and second walls apart and defining a cell between each adjacent pair of connecting wall panels; each connecting wall panel having at least one hole for communication of concrete between adjacent cells; and each first wall panel comprising: an outer wall that extends between the first and second edges of the first wall panel; and an inner wall that extends between the first and second edges of the first wall panel, the inner wall spaced transversely from the outer wall and located relatively more proximate to the second wall panel, wherein one of the inner and outer walls has a generally convex cross section along a length of the first wall panel which protects transversely away from the other one of the inner and outer walls.