The Corotherm 25mm 7Xwall is a premium-grade, lightweight polycarbonate sheet designed for roofing and vertical glazing applications. With its multiwall structure and U-value of 1.4W/m²K, it offers excellent thermal insulation while still being easy to handle and install. Whether you’re working on a conservatory, canopy, or lean-to roof, this sheet delivers durability, energy efficiency, and a clean modern look.
Available in a range of finishes including clear, bronze, opal, as well as dual tints like bronze opal and heatguard opal, Corotherm 25mm 7Xwall can be supplied in full sheets or cut to size. It’s also backed by a reassuring 10-year warranty.
Key Features
Available in clear, bronze, opal, bronze opal, and heatguard opal
Lightweight and impact-resistant
UV protected for long-lasting performance
Excellent thermal insulation (U-value: 1.4W/m²K)
Helps minimise condensation
Self-cleaning surface for low maintenance
Comes with a 10-year manufacturer’s warranty
Ideal For
Porches
Canopies
Carports
Conservatories
Lean-to roofs
Vertical glazing and cladding projects
Installation Guidelines
When installing, ensure the UV-protected side (clearly marked on the sheet) is facing outwards to protect it from sun damage. For optimal drainage, your roof must have a minimum slope of 10°. The sheet’s flutes should always run vertically—from the top of the slope to the bottom. Never install with the flutes running sideways, and note that sheets cannot be joined vertically (top to bottom).
To maintain proper waterproofing, only use low modulus neutral cure sealant and cross-linked butyl flashing tape during installation.
Cutting and Shaping
Cutting Corotherm 25mm 7Xwall is simple and safe. It won’t crack or shatter when cut properly. Use a sharp utility knife for cuts along the direction of the flutes. For cuts across the flutes, a fine-toothed saw works best, while a fine-toothed jigsaw is ideal for any curved shapes.
Thermal Expansion
As with any polycarbonate product, you’ll need to allow for thermal expansion. Leave a gap at the top of the sheet during installation, and always drill fixing holes with an extra 3mm of space around each one. Avoid overtightening or clamping the sheets too tightly to ensure they can expand and contract naturally with temperature changes.
Cleaning and Maintenance
Cleaning your Corotherm sheet is easy. Just use lukewarm soapy water with a soft cloth or sponge. Avoid harsh brushes, sharp tools, or abrasive or high-alkaline cleaning products that could damage the surface. Thanks to its UV-resistant and smooth surface, the sheet is largely self-cleaning.
10-Year Warranty
The Corotherm 25mm 7Xwall comes with a 10-year warranty covering any failure due to manufacturing defects under normal weather conditions. If an issue arises within this period, a replacement sheet will be provided free of charge. However, the sheet must be installed and maintained according to the manufacturer's instructions for the warranty to remain valid. Please note that the warranty does not cover reinstallation or any related damage.
Frequently Asked Questions
1. What makes the 25mm 7Xwall better for insulation?
Its triple-wall, 7X structure provides excellent thermal insulation with a U-value of 1.4W/m²K. This means it helps retain heat better than thinner sheets, making it a great choice for conservatories and enclosed spaces.
2. Can I install this sheet for a flat roof?
No, flat installation is not recommended. The roof should have at least a 10° pitch to allow water to run off properly. Installing it flat can lead to water pooling and reduce the lifespan of the sheet.
3. Is heatguard opal different from regular opal?
Yes, heatguard opal is a dual-tint option designed to reflect more solar heat while still allowing light through. It’s ideal for spaces where you want to reduce heat build-up, like sunrooms or greenhouses.
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