Sandwich SHEET metal roof system

COMPACTMETAL TR is our patented, self-supporting long-rail substructure for roof-parallel PV installation on sandwich-panel roofs. Wind and snow loads are transferred via sandwich panel fasteners, the long rail, and defined support points—and from there into the load-bearing substructure. The panel’s outer layer thus bears only the load it is designed to carry. The system has received general building authority approval.

For sandwich-panel roofs. The reason lies in the construction of these roofs: The outer layer of a sandwich panel is a thin sheet of metal, not a load-bearing surface—it can only bear a limited portion of the loads. COMPACTMETAL TR therefore transfers wind and snow loads past the panel and into the underlying purlins; the self-tapping screw is suitable for both wood and steel purlins. The structural analysis for each individual project determines the maximum load the panel can withstand.

“Self-supporting” means that the TR long rail spans large distances and bears the loads itself, rather than transferring them across its entire surface to the roof covering. It rests on defined fastening and support points, the positions of which are determined by the structural analysis—in between these points, it does not come into contact with the panel. This separates the load types: Wind loads are transmitted exclusively through the sandwich fasteners and the rail, while snow loads are transferred to the substructure via the patented support concept. It is precisely this separation that relieves the panel of stress.

In two ways. Statically, by using the patented support concept to separate the load types and calculating the positions of the intermediate supports so that the rail does not come into contact with the panel between the supports. And structurally at every single penetration point: The TR15 sandwich bridge sits on the high rib with a spacer and integrated rubber seal, and the self-tapping screw transfers the load through the panel into the purlin. As a result, the top layer is subjected to loads only within the project-specific permissible limits, while the rubber gasket and optimized self-tapping screw seal the penetration.

It determines where fasteners and intermediate supports must be located in a specific project. The calculation is based on snow, wind, and dead-load loads, as well as the stiffness of the sandwich panel. The algorithm calculates both a lower and an upper limit for the panel stiffness; the more unfavorable case is used to determine each support reaction. This results in support reactions, the number of screws, and, if necessary, additional module supports; the optimization calculation continues until all structural verifications are satisfied. The determining factor for the intermediate supports is the distance remaining between the module support and the roof covering after deflection.

In terms of height and, consequently, load-bearing capacity. TR74 is the 15-millimeter-taller rail and is designed for locations with high snow and wind loads; TR59 is the shorter version for normal load conditions. The selection is not based on roof size, but rather on the load assumptions at the site and the project-specific structural design.

The documentation required for a specific project depends on the actual panel installed and the manufacturer’s specifications. To clarify these details before installation, the panel type, the structure of the substructure, and the location are needed.

Yes, the system is designed for that. The load-bearing capacity results from the combination of the rail profile and the support concept: For high loads, the taller TR74 rail is used, and the structural analysis algorithm adds additional modular beams as needed until all structural verification requirements are met. The specific design for each location is determined by span lengths, panel stiffness, and local load assumptions.

Yes. The general building code approval for COMPACTMETAL TR is available in the download section; it contains the technical guidelines for planning and design verification. In addition, there is a leaflet for preselection, an intake form for project preparation, and assembly instructions for execution—the leaflet is also available in English and Italian, while the intake form and assembly instructions are in English. For project-specific design, the panel type, substructure, and location are required; AEROTOOL uses this information to calculate, among other things, support reactions and the number of screws.