Abstract: A building panel having a vertical face portion and integral upper and lower horizontal portions, together defining a U-shape, is disclosed. The building panel is intended for installation on the vertical face of a building adjacent another building panel or other building element, with sealant between the upper portion and the other building panel or other building element at a seal location near the face portion, and with the upper and lower portions directed towards the face of the building. The upper portion has a downwardly-directed channel defined therein, running generally parallel to the face panel behind the seal location, to collect moisture. The channel has at least one drain hole in the bottom thereof. The moisture drops through the drain holes onto the lower portion, and drains away from the building from there. The building panel system includes a complementary U-shaped positioning element having a vertical mounting surface and integral upper and lower horizontal positioning surfaces.