Overview of metal structures for rooftop solar power plants

A rooftop solar power plant is a source of clean energy for businesses, an opportunity to reduce electricity costs and turn roof area into an asset. When installing a rooftop solar power plant, it is important to take care of reliable and optimal metal-consuming solutions for mounting solar modules. Modern models of metal structures manufactured by KNESS allow mounting solar modules on various types of roofs while maintaining reliability, hydro and thermal roof insulation. All thanks to a competent approach to the development of design solutions by our RnD team and comprehensive experience in supporting metal structures production.

We will review existing models of supporting structures for rooftop solar power plants and ways of choosing the best option.

Rooftop metal structures for pitched roofs with metal coating

For pitched roofs with a metal coating, KNESS offers two models of metal structures with different types of fasteners, namely invasive and non-invasive, depending on the roof’s strength.

Supporting metal structure with bracket mounting method

The first is a supporting metal structure mounted on brackets. The installation of such metal structures involves reliable mechanical fastening to the roof beam using brackets. This model is universal, as it is suitable for different types of photovoltaic modules (PV modules), adapts to any unevenness and roof shape, is resistant to atmospheric loads, and, importantly, has minimal pressure on the roof. 

This mounting type is the most reliable in terms of the durability of fixing solar modules to the roof. However, this model is only suitable for those roofs for which the intrusion of the mounting systems into the roof does not hinder load-bearing capacity.

Supporting metal structure with adhesive fastening method

An alternative non-invasive option for installing a solar station on a pitched roof with a metal roof is to use a supporting metal structure with an adhesive fastening method. It involves the use of a high-strength, one-component silicone adhesive that enables to securely fix the metal profile to the roof without damaging its integrity. The adhesive we use to fasten this type of metal structure has high tensile strength under dynamic loads and is also resistant to temperature, UV, and atmospheric loads. 

The main advantage of using adhesive metal structures is their compatibility with roofs that are not suitable for invasion. These include, for example, roofs covered with sandwich panels or a thin layer of metal with an unreliable base (old wooden beams), etc.

Rooftop metal structures for flat roofs with concrete, roofing felt, or membrane coating

Structures for installing solar power plants on flat roofs with various coating types differ in the presence or absence of ballast, which are special concrete blocks that provide additional fixation of the structure while maintaining the integrity, waterproofing, and thermal insulation of the roof. KNESS produces ballasted steel structures.

Supporting metal structures for flat roofs must securely fix the solar panels on the roof, be resistant to wind and snow loads, and at the same time exercise minimal pressure on the roof. Accordingly, single-pitched or  double-pitched models of metal structures with an optimal inclination angle are used on flat roofs to maximize the performance and efficiency of solar panels. Single-pitched metal structures are most frequently installed with an eastward orientation and double-pitched structures with an east-west orientation.

Since the ballast adds weight to the entire structure, before installing a PV system, engineers must inspect the technical condition of the roof and the building itself for the load-bearing capacity. They also calculate the local and distributed pressure on the roof to determine the optimal weight of the ballast system. Accordingly, lightweight ballast blocks can also be used if the wind load conditions at the location of the PV plant make it possible. When installing a PV system on a roof with a membrane coating, we additionally use specially designed substrates made from recycled rubber crumbs, which further reduce local pressure on the roof, protect the roof material and metal structure from water.

Can solar power plants be installed on roofs with other types of coating?

There are solutions for mounting PV modules for different types of roofs on the market, but we have seen from our own experience that metal structures can be securely fixed only on roofing felt, membrane, concrete, and metal roofs. We do not recommend installing solar power plants on other types of roofs, such as slate, ceramic tiles, or wood, as there is a high risk of damage to the integrity of the roof and leaks.

KNESS develops and manufactures reliable and metal-optimized support structures for rooftop solar power plants. As of the beginning of 2024, 16 rooftop solar power plants with a total peak capacity of more than 8 MW have been built with our metal structures. But our production is not limited to support systems for rooftop power plants. In 2023 alone, we produced more than 700 tons of steel structures for export to European countries. In addition, our comprehensive 14-year experience in EPC contracting in the solar energy sector gives us an understanding of the full life cycle of metal structures. This helps us develop and manufacture a high-quality end product. We offer solutions that can be adapted to different types of roofs, panel sizes, and capacities. We can also design and manufacture support systems individually tailored to customer needs. Learn more about metal structures by KNESS here.