Telescopic steel roof truss turnup for building

The invention relates to the technical field of house structures, in particular to a telescopic steel roof truss flange for a building, which comprises a main body forming an upper arch space structure, and the lower part of the main body is opened and is used for covering a transverse and longitudinal beam connecting seam of a steel roof truss; the main body extends along a straight line and is connected and fastened with a steel roof truss through a connecting structure at a lower opening of the main body; the outer top surface and the inner top surface of the upper arch space structure are provided with alignment structures used for being matched with the adjacent main bodies correspondingly. The flanges cover the splicing positions of the cross beams and the longitudinal beams of the steel roof truss, and water and sundries are prevented from entering the splicing positions to damage a building structure; the plurality of turnups can be connected in a matched mode to form a telescopic adjustable structure