Introduction: Flat Roofs – The “Blue Ocean” Battlefield for Distributed PV

As distributed PV shifts from “policy‑driven” to “economically driven”, flat roofs – with their high space utilisation and flexible array layout – have become an important application scenario for commercial and public building PV installations. In 2024, the flat roof PV mounting field saw multiple technological innovations: from AEROCOMPACT‘s click‑fit fast‑install system to RAULI’s vertical installation with welded fixation; from EPC Solaire‘s lightweight waterproof integrated system to Sun Ballast’s modular ballasted solution – manufacturers are focusing on three core directions: installation efficiency, roof protection, and extreme weather adaptability.

Part One: AEROCOMPACT – Click‑Fit Fast‑Install System Targets the North American Market

In August 2024, Austrian PV mounting expert AEROCOMPACT officially launched the COMPACTFLAT S_BASE flat roof fast‑install system at the RE+ exhibition in North America, aiming directly at the US flat‑roof PV market.

Key Highlights:

Christian Ganahl, CTO of AEROCOMPACT, said: “S_BASE is our most cost‑effective long‑side clamping system, designed specifically for large‑format modules and high wind/snow loads. We will revolutionise the US flat‑roof PV market with this system.”

Design tool upgrade: AEROCOMPACT also launched the AEROTOOL.CAD plugin, allowing designers to complete full‑process design – layout, stringing, energy simulation, shading simulation, cable tray optimisation, ballast calculation, generation simulation – within the AutoCAD environment, and export to PVSyst for further analysis.

Part Two: RAULI – Vertical Installation + Welded Fixation, a Nordic Approach Challenges Conventions

In July 2024, Nordic mounting system manufacturer RAULI launched the innovative RAULI FLAT flat‑roof system, featuring unique vertical installation and welded fixation.

Technical Breakthroughs:

Ville Tiainen, CEO of RAULI, noted: “Vertical installation allows 20% more solar panels in the same row, with fewer components, and the cost per panel is 15‑20% lower than horizontal installation.”

Unique advantages: The same modules can be used for both east‑west and south‑facing installations. The RAULI APP calculates the number of modules, system weight, product carbon footprint, and generation estimates. This solution is particularly suitable for regions with high snow loads, such as Northern Europe, as it requires no additional snow supports.

Part Three: Sun Ballast – Modular Ballasted System, No Roof Penetration

In 2024, Sun Ballast‘s single‑row ballasted system was deployed in several projects across Europe. Its core concept is to fix the mounts using concrete ballast blocks, completely avoiding penetration of the roof waterproofing membrane.

Naples, Italy – 12 kWp project (October 2024):

Tilt angle: 20°

Single‑row system, adjustable in length and row spacing

Concrete ballast blocks incorporate M8 bushings and metal cores for enhanced stability

Optional U‑shaped additional ballast blocks (30 kg) and Cablowind concrete cable trays to improve wind resistance

Vilamoura, Portugal – 30 kWp project (November 2024):

Installed on the flat roof of a new residential building

Tilt angle: 5°, single‑row system

Adjustable row spacing to flexibly accommodate roof obstacles

Suitable for residential, industrial and commercial installations

System features:

Tilt angle range: 0° to 30°

Compatible with both long‑side and short‑side module fixing methods

Suitable for various flat surfaces – gravel, paved, green roofs, etc.

No roof penetration, avoiding leakage risks

Part Four: EPC Solaire – Dedicated to Renovation Scenarios, Lightweight Waterproof Integrated System

In December 2024, French mounting system supplier EPC Solaire launched a new mounting system specifically designed for flat roofs undergoing renovation, developed in partnership with French roofing specialist Sika and insulation material supplier Recticel.

Technical Breakthroughs:

Ferrer Payen, Managing Director of EPC Solaire, said: “We designed a solution that protects the existing ribbed metal sheet roofing, avoiding any roof exposure and operational losses. It combines full renovation of the waterproofing layer, installation of Class C insulation material, and installation of solar modules.”

The system is entirely made of aluminium produced in France and preserves the integrity of existing components. This solution is particularly suitable for commercial and industrial roof renovation scenarios, integrating waterproofing renovation, insulation upgrade, and PV installation into a “one‑stop” solution.

Part Five: 2024 Flat Roof Mount Technology Trend Summary

Outlook

Looking ahead to 2025 and beyond, flat roof PV mounting systems will continue to deepen development in the following directions:

Installation efficiency revolution: Click‑fit installation, bolt‑free designs, telescopic rails and other innovations will further shorten construction periods and reduce labour costs

Roof protection upgrades: Non‑penetrating ballasted solutions and lightweight designs will continue to gain market favour, protecting roof waterproofing membranes and structural integrity

Vertical installation proliferation: Solutions such as RAULI demonstrate that east‑west installation can increase space utilisation by 20%, and are likely to be applied in more scenarios

Renovation market growth: As existing building roofs age, integrated “waterproofing + insulation + PV” solutions like EPC Solaire‘s will see larger markets

Smart design software: Integrated design tools such as AEROTOOL.CAD will become standard competitive differentiators for mount manufacturers

In a Nutshell

In 2024 – from AEROCOMPACT’s click‑fit fast‑install system to RAULI‘s vertical welded solution, from Sun Ballast’s non‑penetrating ballasted system to EPC Solaire‘s renovation‑integrated solution – flat roof PV mounting is moving forward with lighter, faster, and smarter approaches to meet the wave of large‑scale distributed PV deployment.