Double-lock standing seam technology – it is a system of rules, technological methods and nodes, which allows you to implement the task of constructing a roof from a flat metal sheet. Accordingly, the simpler the initial shape of the workpiece, the more complex the configuration of the finished roofing element.

"Double-lock standing seam system"  - is a set of elements that are in relationships and connections with each other and form a single whole. This system serves as a tool for studying the phenomena and processes occurring on a metal roof.

Double-lock standing seam system uses the subject-thematic principle of organizing the description of coating units assembled using the double fold technology and methods for their implementation. Thus, the “Double Seam System” can be presented as a list of topics and chapters, the content of which contains a description of one or another group of roofing nodes related to the corresponding part of the roof.

"Basic course. Double-lock standing seam system" - describes the units and methods for their implementation associated with the formation of a coating from a metal sheet, their types and general layout principles. Section “Skates. Valleys. Ends and Overhangs" (which is included in the "Basic Course") - respectively, serve to describe the intersection nodes of the ordinary covering of roof slopes in these crucial places.

"Pipes and penetrations" - a specialized section that describes how to form junctions and transitions of the seam roofing on the vertical surface of the roof passage elements that cross the main roofing of the slopes.

Separate specialized sections are "Above-the-wall and built-in gutters" and "Dormers and skylights". These sections have received the right to a detailed description due to the large number of unique and specialized intersections of roofing elements, which are realized only when such elements as wall gutters or a huge number of types of windows are made on the roof.

The principle that unites these groups of nodes and technological methods is the use of a double seam connection. The description also applies to all other methods of joining parts of a metal sheet covering (single seam, corner seam, fold, etc.), but they are considered only as constituent elements of the “Double-lock standing seam system” and are not considered separately, in isolation from it.

Very little attention is paid to the soldering of metal elements of the coating as a method of connection, which radically changes the technology for the production of works using the double seam technology and should be considered in a separate publication.