The Corotherm 25mm 7Xwall sheet by Ariel Plastics is a high-performance polycarbonate roofing and glazing solution designed for energy efficiency and durability. Its advanced 7-wall structure offers superior strength and a low U-value of just 1.4W/m²K, helping to retain heat in enclosed areas like conservatories, carports, and lean-to roofs.
Despite its strength, the sheet remains lightweight and easy to handle, making it suitable for both DIY and professional installations. Its clear finish provides excellent light transmission, while a range of other tints—like bronze, opal, bronze opal, and heatguard opal—let you tailor the sheet to your project’s lighting and heat control needs.
Backed by a 10-year warranty, it’s a reliable long-term investment for any roofing or glazing application.
Key Features
Available in clear, bronze, opal, bronze opal, and heatguard opal
Strong yet lightweight and impact-resistant
UV-protected for long-term clarity and performance
Excellent thermal insulation (U-value: 1.4W/m²K)
Helps reduce condensation
Self-cleaning surface for easier maintenance
Supplied with a 10-year manufacturer’s warranty
Ideal For
This sheet is particularly well-suited for:
Porches
Canopies
Carports
Conservatories
Lean-to roofs
Vertical glazing or cladding
Its insulating properties make it especially valuable for enclosed structures where energy efficiency matters.
Installation Guidelines
Before installing the sheet, make sure the UV-protected side (which is clearly marked) is facing outward to shield it from sun damage. The roof should be installed at a minimum pitch of 10° to allow proper water drainage.
The flutes must always run vertically, from the top of the slope down to the bottom. Installing them sideways prevents proper drainage and may compromise the sheet’s structural integrity. Also, sheets cannot be joined vertically from top to bottom.
For a watertight seal, use low modulus neutral cure sealants and cross-linked butyl flashing tape only, as recommended by the manufacturer.
Cutting and Shaping
The Corotherm 25mm 7Xwall sheet is easy to work with and won’t crack or splinter during cutting when handled correctly. If you're cutting along the flutes, a sharp utility knife is ideal. For cross cuts, use a fine-toothed saw. To shape the sheet into curves, a fine-toothed jigsaw will give you clean, smooth results.
Thermal Expansion
Like all polycarbonate products, these sheets expand and contract with temperature changes. Always allow for thermal movement during installation by leaving a small gap at the top of each sheet and drilling holes 3mm larger than the fixings.
Avoid over-clamping or tightening, as this restricts expansion and could lead to cracking or buckling over time.
Cleaning and Maintenance
Keeping your sheet clean is straightforward. Just wash with lukewarm soapy water and a soft sponge or cloth. Avoid abrasive tools, hard brushes, or strong alkaline cleaners, which can scratch or damage the surface.
Thanks to the UV-protected coating and smooth finish, the sheet naturally repels dirt and debris, making maintenance low-effort.
10-Year Warranty
Each Corotherm 25mm 7Xwall sheet comes with a 10-year warranty against manufacturing defects under normal weather conditions. If an issue arises due to a factory fault within this period, a free replacement will be provided.
However, the warranty is only valid if the sheet is installed and maintained correctly, following all manufacturer instructions. It does not cover reinstallation costs or secondary damage.
Frequently Asked Questions
1. What makes the 25mm 7Xwall better for insulation?
The 7-wall structure of this sheet traps air between multiple layers, which significantly reduces heat transfer. With a **U-value of 1.4W/m²K**, it offers better thermal performance than thinner alternatives—making it ideal for conservatories and enclosed roofs where insulation is key.
2. Can I install this sheet on a flat roof?
No, flat installation isn’t advised. The roof must have a **minimum 10° pitch** to allow water to drain away properly. Installing the sheet flat can cause water pooling, which shortens the lifespan and may void the warranty.
3. What’s the difference between heatguard opal and regular opal?
While both offer light diffusion, **heatguard opal** is a dual-tinted option designed to **reflect more solar heat**. It helps keep interior spaces cooler, making it a better choice for sun-exposed areas like **greenhouses, sunrooms, or south-facing roofs**.
Check out our full range of roofing supplies.
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