The factory roof is one of the most critical elements in industrial facilities, directly impacting a business’s operational efficiency. A well-designed factory roof not only protects the facility from weather conditions but also contributes to creating a safe and comfortable working environment for employees. In this article, KTG Industrial provides an in-depth overview of industrial factory roofs, including their structure, classification, and key considerations when selecting the most suitable roofing solution.
What is a factory roof?
The factory roof is the structural component located at the highest point of the building, playing a key role in protecting the entire space below.
The primary function of the factory roof is to block external environmental impacts such as rain, sunlight, wind, and dust—ensuring safety and operational stability for production activities. In addition, the factory roof helps maintain ideal temperature and humidity levels, creating a favorable working environment for employees. Choosing the right materials and roof design contributes to long-term cost efficiency and extends the building’s lifespan.
A factory roof is typically constructed with three main components: a robust structural frame, a system of trusses and protective roofing sheets, and a set of fasteners. The structural frame serves as the primary load-bearing element, ensuring the overall stability of the roof. The truss and roofing sheet system forms a protective layer that shields the facility from weather elements. Fasteners play a crucial role in securely connecting all components, creating a complete and durable roofing structure.
The factory roof is an essential component that protects and preserves the overall structural integrity of the entire facility.
Industrial factory roof structure
The structural design of an industrial factory roof is a key factor that determines the durability and protective performance of the entire facility. To ensure efficient production operations and secure storage of goods, the roof structure must be built to be strong and stable. Below are the three main components of a typical industrial roof structure:
Load-bearing structure
The load-bearing structure is responsible for supporting the entire roof load as well as resisting environmental forces such as wind and rain. The materials and configuration of the load-bearing system depend on the type of roof:
- Flat roof: Typically utilizes purlins, trusses, and rafters.
- Sloped roof: Commonly incorporates beams and prefabricated panel systems.
Protective roofing layer
The protective roofing layer plays a vital role in shielding the facility from environmental elements such as sunlight, wind, rain, and storms—safeguarding the factory and enhancing the overall durability of the structure. A wide range of materials can be used for this layer, including tiles, corrugated metal sheets, concrete panels, bitumen membranes, and fiber cement boards.
Bracing system
The bracing system ensures the rigidity, strength, and overall stability of the roof while enhancing the structural connection between roofing components. Common types of bracing include roof bracing, purlin bracing, and gable end bracing, typically made from tension cables or steel tubes.
An industrial factory roof consists of three main components: the load-bearing structure, the protective roofing layer, and the bracing system.
Factory roof construction
Industrial factory roofs share a common structural composition, with the load-bearing system playing a pivotal role. This system consists of three main components:
- Main frame: This is the core structural element responsible for supporting the entire roof, ensuring overall stability and strength. It is typically composed of steel columns, trusses, and beams designed to handle heavy loads and large spans. The frame profile may vary (L-shaped or H-shaped) depending on the architectural design.
- Transverse frame: Includes crane beams, roof structures, bracing systems, and wall support elements. A key feature of the transverse frame is its longitudinal orientation, which enhances rigidity and lateral load resistance.
- Secondary frame: Comprising elements such as wall beams, struts, and roof purlins, the secondary frame reinforces the structural integrity of the entire roof system. These components are often arranged in overlapping Z-shaped configurations to improve strength and stability.
A factory roof structure must be robust to ensure long-term and uninterrupted production operations.
What is the Roof Slope of a Factory?
The roof slope of a factory refers to the angle of inclination between the roof and the horizontal plane. It plays a critical role in rainwater drainage and structural protection. A properly designed roof slope allows rainwater to drain quickly, preventing water accumulation, leakage, and potential damage to the building’s longevity.
The slope of a factory roof depends on several factors, including roofing materials, structural design, and local climate conditions.
Roof Slope Formula: i = (H/L) x 100%
Where:
- i is the roof slope (in percentage)
- H is the height difference between the highest and lowest points of the roof
- L is the horizontal span of the roof
The slope of a factory roof is expressed as a percentage (%).
According to TCVN 4604:2012 – the Vietnamese national design standard for industrial enterprises – production buildings, this regulation outlines the design requirements for production facilities within industrial zones. Among its provisions are specific requirements related to factory roof design, including the following:
| Roof types | Minimum slope (%) |
| Asbestos-cement roofing sheets | 30% – 40% |
| Corrugated metal sheet roofing | 15% – 20% |
| Tiled roofing | 50% – 60% |
| Reinforced concrete panel roofing | 5% – 8% |
Additional notes:
- For small roofing materials with multiple joints prone to leakage—such as tiles—a steeper slope is required to ensure quick rainwater drainage. The typical ratio is 1:2.
- When using larger sheet materials with fewer joints—such as fiber cement tiles—the required slope can be reduced to 1:3.
- For monolithic roofing materials with no joints—such as reinforced concrete—the roof can be nearly flat, with a slope of around 2% (equivalent to 1:50).
Types of factory roofs
Industrial factory roofs come in a wide variety of types, depending on factors such as form, material, and structural design. Each roof type has its advantages and disadvantages, making it suitable for specific applications and project conditions. The following table outlines the most common types of factory roofs used today:
| Classification criteria | Roof types |
| Based on roof structure | Factory roof with purlins |
| Factory roof without purlins | |
| Based on roofing material | Tiled roof |
| Reinforced concrete roof | |
| Corrugated metal sheet roof (commonly referred to as metal roofing) | |
| Based on roof form/design | Flat roof |
| Sloped roof | |
| Curved or complex-shaped roof (e.g., arched roof, vaulted roof) |
Based on the roof form
Flat roof
A flat roof features a very low slope or is nearly horizontal. It is easy to construct, cost-effective and allows for efficient use of rooftop space. However, flat roofs have poor drainage capacity and are more prone to leakage if proper waterproofing is not applied during construction.
Sloped roof
A sloped roof has a defined angle, allowing rainwater to drain off easily. Compared to flat roofs, sloped roofs offer better drainage and thermal insulation while also providing a more aesthetically pleasing appearance. However, they are more complex and expensive to build.
Sloped roofs drain well, insulate better, and look nicer, but cost more and are harder to build than flat roofs.
Curved or arched roof
An arched roof features a curved form that adds a distinctive architectural highlight to the building. It provides good drainage performance and is well-suited for projects with high aesthetic requirements. However, constructing an arched roof requires advanced technical expertise and involves higher costs.
Arched roofs, with their distinctive curved design, offer high aesthetic value and effective drainage, but require advanced construction techniques and higher costs.
Based on roofing material
Tiled roof
Tiled roofs offer a traditional aesthetic and provide excellent thermal insulation. However, they are relatively heavy, requiring a strong load-bearing structure and higher construction costs. In addition, tile roofs are prone to moss and mildew buildup and require regular maintenance.
Tiled roofs look great and insulate well but are heavy, costly to install, and need regular maintenance.
Reinforced concrete roof
Reinforced concrete roofs offer high durability along with excellent waterproofing, sound insulation, and fire resistance. This type of roof can bear heavy loads and is less affected by strong winds, hail, or corrosive environments. It is also well-suited for integration with thermal insulation and waterproofing layers, enhancing overall performance. Thanks to these properties, concrete roofs are ideal for buildings that require long-term structural stability.
However, concrete roofs come with some disadvantages. They are expensive to construct and require longer completion times. When water leakage or cracking occurs, repairs can be difficult and costly. In addition, the rigid structure of concrete roofs limits flexibility in future renovations, making them less adaptable in terms of architectural design.
Concrete roofs are durable, waterproof, and sound-insulating, with high load-bearing capacity, but they involve high construction costs and longer build times.
Corrugated metal roof (steel roofing sheets)
Corrugated metal roofs are the most commonly used roofing type in industrial factories due to their low cost, quick installation, lightweight nature, and ease of dismantling or relocation. In addition, they offer good weather resistance and come in a wide range of designs and colors, helping optimize both project cost and aesthetic appeal. Especially for warehouses, metal roofs are a practical and economical choice as they allow for better ventilation.
However, metal roofs have certain drawbacks. They provide poor thermal insulation and tend to absorb heat, making the space beneath uncomfortably hot—particularly during summer—potentially affecting the working environment and the storage of goods. Moreover, metal roofs can generate significant noise during heavy rain, reducing acoustic comfort within the facility.
Metal roofs are cheap, light, quick to install, and weather-resistant, but insulate poorly and can be noisy in the rain.
Based on the roof structure
Factory roof with purlins
This type of roof utilizes a purlin system to support the roofing sheets. The use of purlins enhances the roof’s load-bearing capacity, making it especially suitable for buildings with large spans. However, factory roofs with purlins typically involve higher construction costs and longer build times compared to those without purlins.
Purlin Strength: The commonly used purlin strength is G350, depending on the structural requirements of each project.
Purlin Spacing: The spacing between purlins depends on the span of the structural beams and the slope of the roof. Standard purlin spacing usually ranges from 1.1 meters to 1.4 meters.
Note: For auxiliary production buildings using wooden purlins, the column spacing must not exceed 3.9 meters.
Factory roof without purlins
Factory roofs without purlins utilize self-supporting roofing panels or are combined with a simplified truss system. This roof type is more cost-effective and allows for faster construction compared to purlin-supported roofs. However, its load-bearing capacity is lower, making it more suitable for buildings with shorter spans.
Key considerations for factory roofs
To ensure that the factory roof performs efficiently and remains durable over time, the following aspects should be taken into account:
Structural durability
- Select appropriate roofing materials and structural systems that meet load-bearing and weather-resistance requirements.
- Ensure proper construction techniques are followed to guarantee the quality and longevity of the building.
- Regular maintenance and inspections should be conducted to detect and promptly address any potential damage.
Fire safety compliance
- Use fire-resistant or non-combustible roofing materials.
- Install automatic or semi-automatic fire suppression systems.
- Ensure that emergency exits and fire alarm systems are fully operational and compliant with current regulations.
The roof of an industrial factory plays a vital role in protecting the facility and maintaining uninterrupted production operations.
KTG Industrial – Advancing green industry with rooftop solar energy systems
Solar panels on KTG Industrial’s rooftops boost energy efficiency and reflect the company’s commitment to sustainability.
As part of its sustainable development strategy, KTG Industrial is pioneering the integration of rooftop solar panel systems across several projects, including KTG Industrial Tam Phuoc A, KTG Industrial Tam Phuoc B, KTG Industrial Nhon Trach 2 (Phase 1), KTG Industrial Nhon Trach Textile, and KTG Industrial Nhon Trach 3A. The roofs are specially designed to optimize solar panel installation, helping reduce reliance on the conventional power grid while significantly cutting annual CO₂ emissions.
This initiative is not only an energy-saving solution but also a concrete step toward KTG Industrial’s Net Zero goal—achieving carbon neutrality in industrial operations. It aligns with Vietnam’s commitments made at COP26 and reinforces the company’s dedication to green, responsible growth.
Conclusion
Choosing and designing the right factory roof plays a vital role in protecting the building, ensuring a safe working environment, and optimizing production efficiency. We hope this article has provided you with a comprehensive overview of roof structures, classifications, and key considerations in industrial roof construction—helping you make informed decisions that best suit your business needs.
