eave element 48 has a flat undersurface 49 which is adapted to lie along the upper edges of the rafters 12 the upper surface 51 of the eave element consists of a series of flat surfaces of plank width lying at an angle to the undersurface which flat surfaces are joined by curved transition surfaces to resemble a plurality of plank elements a tail member 52 extends from the main body in the plane of the undersurface referring to fig8 it can be seen that a roof structure is shown in which a plank 53 has a flat undersurface 54 which is adapted to lie along the upper edges of the rafters 12 the upper surface 55 consists of a series of flat surfaces of plank width lying at an angle to the undersurface 54 and joined by curved transition surfaces to resemble a plurality of plank elements 16 the lower edge is recessed to form a nose 56 that overlies the upper edge of the next lower eave or plank element and to receive the tail member of that next lower element a tail member 57 extends from the main body of the plank element 53 in the plane of the undersurface 54 fig1 shows a roof structure which makes use of an eave element 58 which overlies the lower ends of false rafters 59 and locks into a purlin 14 the element 58 is similar in.