Weathering the Elements: Corrugated Roofing Sheets vs Solid Glazing Roofing Sheets

When it comes to roofing sheets, there is a wide array to choose from. Popular choices include corrugated roofing sheets and solid glazing roofing sheets and both differ in terms of durability and overall performance. For this feature, we delve deeper into the benefits and properties of each option. We explore factors such as weather resistance, insulation properties and maintenance requirements. 

What is a solid glazing and corrugated roofing sheet?

Corrugated roofing sheets are made of materials like steel, plastic, aluminium or fibre cement. They feature a repeating wave-like pattern of ridges and grooves running along their length. This corrugated design adds structural strength and facilitates water runoff. 

Solid glazing roofing sheets are flat, smooth panels typically made from clear or translucent materials such as polycarbonate, acrylic or fibreglass. Unlike corrugated sheets, they have a continuous, non-segmented surface. It allows natural light transmission into the building below. 

What are the differences between corrugated and solid glazing?

From weathering abilities and durability to light transmission and insulation properties, these two roofing materials differ in several key areas. Below, we outline these 4 performance differences in detail. 

1. Applications and usage

Corrugated roofing sheets are primarily used in industrial, agricultural and commercial buildings where durability, low maintenance and cost-effectiveness are priorities. For example, a warehouse, shed, barn and other larger structures would use corrugated sheets.

However, solid glazing roofing sheets are more prevalent in residential, commercial and greenhouse settings. This is because natural light transmission and thermal insulation are more beneficial for applications such as skylights, sunrooms and conservatories.

2. Weathering and durability

Metal, aluminium and steel corrugated roofing sheets are highly durable and resistant to weathering. Their corrugated design allows water to easily run off, preventing pooling and minimising the risk of leaks. Plus, metal corrugated sheets are fire-resistant and can withstand extreme temperatures. However, they may be susceptible to denting from impacts or corrosion over time if not properly maintained.

Solid glazing acrylic or polycarbonate roofing sheets offer excellent weathering resistance because of their non-porous nature. They are not prone to rusting, rotting or warping and can withstand UV radiation without significant degradation. However, they may become brittle and prone to cracking over extended periods of exposure to extreme temperatures.

3. Light transmission and insulation

Solid glazing roofing sheets can transmit natural light into the building interior. They allow up to 90% light transmission which leads to energy savings by reducing artificial lighting use. Also, they provide excellent thermal insulation which helps regulate interior temperatures. 

However, corrugated metal roofing sheets are opaque and do not allow any natural light transmission. This can result in a darker interior space, requiring more artificial lighting. While not insulating, both sheet types can be paired with insulation materials. For example, rigid foam boards or blankets can be used to improve thermal performance. 

4. Weight and load-bearing capacity

Metal, aluminium, steel and corrugated plastic roof sheets are generally lighter in weight compared to solid glazing sheets. This makes it easier to install, particularly for large-scale projects. They also have a higher load-bearing capacity, which can be beneficial in areas prone to high winds.

Thick acrylic or solid glazing polycarbonate sheets for roofing can be heavy. They may require additional structural support and reinforcement. However, their strength and impact resistance makes them suitable for applications where resistance to hail and debris is a concern.

How to install solid glazing and corrugated roof sheets

The installation of corrugated roofing sheets is a different process compared with solid glazing roofing sheets. This is primarily because of the contrasting material properties and structural requirements of each system. Here, we detail the key differences to consider.

Corrugated roof sheet

• Corrugated roofing sheets are typically installed over a supporting framework of purlins or battens. Using a supporting framework of purlins or battens is crucial because it provides the necessary structural strength and spacing to properly secure the corrugated sheets. 
• Proper spacing allows for overlapping and interlocking of the sheet ridges.
• The installation process often begins with laying an underlayment or vapour barrier over the purlins. This provides an additional layer of protection against moisture and condensation. 
• Corrugated sheets are then placed vertically to the purlins using a drill. Ridges should overlap the grooves of the adjacent sheet to create a weathertight seal. 
• An underlayment or vapour barrier is important for preventing moisture infiltration from below. It can lead to corrosion, rot or degradation of the roofing materials and supporting structure.
• Specialised fasteners, such as rubber-washer screws or nails, are used to secure the corrugated sheets to the purlins. These fasteners must be compatible with the sheet material to prevent corrosion. 
• Using compatible fasteners is key to preventing corrosion between dissimilar metals. They also ensure a secure and long-lasting attachment to the purlins.
• Depending on the project requirements, additional flashing and sealants may be applied around penetrations, ridges and eaves to enhance weatherproofing. 
• Proper flashing and sealants are important to prevent water intrusion.

Solid glazing roof sheet

• When you lay solid glazing roofing sheets, they require a more robust and precise supporting structure. This is because of their weight and potential for deflection under load. 
• A sturdy frame made of materials like aluminium or steel is essential for supporting the weight and potential deflection of solid glazing sheets. It prevents sagging or structural failure over time.
• The process typically involves constructing a sturdy frame, often made of aluminium or steel, with rafters or purlins. Spacing the purlins or rafters properly ensures the sheets are adequately supported and minimises the risk of excessive cracking.
• Once the frame is in place, install an underlayment or vapour barrier to protect against moisture infiltration. Carefully position the solid glazing sheets on the frame, with their edges resting on the purlins or rafters. 
• An underlayment or vapour barrier helps prevent moisture infiltration from below. This can lead to condensation, mould or degradation of the roofing materials and supporting structure.
• Use specialised glazing gaskets, sealants and aluminium capping systems to secure the sheets and create a weathertight seal along the edges and overlaps. These components prevent water intrusion and accommodate thermal expansion and contraction of the glazing material. 
• Additional support structures, such as cross-bracing or reinforced ridges, may be required to provide extra rigidity and minimise deflection. This ensures the long-term integrity and performance of the roofing system.

How much does maintenance differ between roof sheets?

Maintaining the performance of roofing systems is essential for longevity. However, the maintenance requirements and techniques vary between corrugated and solid glazing roofing sheets. Below are the top maintenance tips to adopt.

Corrugated roof sheets

Surface preparation and recoating

The exposed surfaces of corrugated sheets are susceptible to oxidation and weathering. Periodic recoating is needed to restore protection and appearance. This process is specific to metal surfaces and should typically be carried out every 5-10 years, depending on local environmental conditions.

Fastener inspection and replacement

Fasteners used with corrugated sheets can corrode over time because of their direct contact with the metal sheets. Inspecting and replacing corroded fasteners with compatible ones is crucial to maintain structural integrity. Ideally, this should be done annually or bi-annually.

Debris and vegetation removal

The grooves and ridges of the corrugated profile can trap debris and vegetation growth, which leads to moisture accumulation and corrosion. Clearing these areas should be conducted at least twice a year or more frequently in areas with heavy foliage or debris buildup.

Solid glazing roof sheets

Surface cleaning

The primary concern is maintaining light transmission by keeping the smooth glazing surfaces clean. Specialised cleaners are required to avoid scratching or damaging the glazing material. Cleaning should be carried out at least annually, or more often in areas with heavy dust or pollution.

Gasket and sealant inspection

Unlike metal sheets, the integrity of solid glazing installations relies heavily on the sealants and gaskets that secure and weatherproof the sheets. Regular inspection and replacement are necessary and should be conducted every 2-3 years.

Condensation management

Solid glazing is prone to condensation buildup, which can damage the sheets or surrounding structures. Proper ventilation techniques specific to these roofing systems are often required. Condensation gutters or vents should be inspected and cleaned at least twice a year, or more often in humid or high-moisture environments.

Corrugated vs solid glazing: Which is best?

Throughout this article, we have detailed the key properties of both roof sheet types. The decision on which roof sheet to choose ultimately depends on the specific priorities and requirements of the project. Below, we summarise the main attributes and issues to think about.

Corrugated

Solid glazing