A building system and a method for constructing a building, the system (100) comprising plurality of prefabricated elements (I), the element (1) comprising: a self-supporting insulation panel (2) comprising a rigid insulation material, —a metal frame (3), comprising a pair of sub-frames. The length of the sub-frame (7a, 7b) has a cross-section comprising an attaching arm (10) extending along the corresponding edge surface (6a, 6b), and an intruding section (11) arranged in the attaching arm (10), the intruding section (II) intruding into the insulation element (5). A box-type structure (12) is arranged distally from the intruding section (11) and comprising a closed or partly open construction. The building system further comprises a connecting element (4), having a cross-section basically a shape of a U-profile. The connecting element (4) is arranged on sub-frames (7a, 7b) of two adjacent elements (1).

A building system and a method for constructing a building, the system (100) comprising plurality of prefabricated elements (I), the element (1) comprising: a self-supporting insulation panel (2) comprising a rigid insulation material, —a metal frame (3), comprising a pair of sub-frames. The length of the sub-frame (7a, 7b) has a cross-section comprising an attaching arm (10) extending along the corresponding edge surface (6a, 6b), and an intruding section (11) arranged in the attaching arm (10), the intruding section (II) intruding into the insulation element (5). A box-type structure (12) is arranged distally from the intruding section (11) and comprising a closed or partly open construction. The building system further comprises a connecting element (4), having a cross-section basically a shape of a U-profile. The connecting element (4) is arranged on sub-frames (7a, 7b) of two adjacent elements (1).

A drain device for a screen enclosure having deck sill track portions, where two adjacent deck sill track portions form a pair of deck sill track portions. The device includes a U-shaped body having a first side, a second side, and a top surface extending between the first side and the second side. The body includes a screen attaching side and an opening that forms a drain port under the top surface and between the first side and the second side. The device includes concealed fasteners that couple the U-shaped body between and to the pair of deck sill track portions and so that the top surface of the U-shaped body is flush with a top surface of each deck sill track portion of the pair of deck sill track portions. A screen enclosure system is provided that includes multiple drain devices.