LEXAN™ THERMOCLEAR™
Twinwall and Multiwall polycarbonate sheeting
Lightweight, insulating glazing for pergolas, covered walkways and architectural projects. A versatile multiwall system with UV protection on both sides, for residential and commercial applications.
Sheets & specifications

10 mm twinwall
For residential and smaller commercial projects.
- Sheet widths
- 700 & 1050 mm
- Sheet lengths
- Up to 7.0 m
- Sheet mass
- 1.7 kg/m²
- Thermal U-value
- 3.0 W/m²K
16 mm triplewall
An option for larger projects and improved insulation.
- Sheet width
- 1050 mm
- Sheet lengths
- Up to 6.0 m
- Sheet mass
- 2.7 kg/m²
- Thermal U-value
- 2.27 W/m²K
Other widths, gauges and structures are available subject to stock or minimum order quantities. Confirm your sheet size, colour and glazing system before ordering. Ask Ampelite about availability.
Thermoclear in use
Colours & performance
Compare visible light transmission and solar heat gain for each sheet option.
| Colour | Sheet | Light transmission | SHGC |
|---|---|---|---|
| Clear | 10 mm | 81% | 0.85 |
| Opal | 10 mm | 64% | 0.71 |
| Bronze | 10 mm | 35% | 0.55 |
| Grey | 10 mm | 20% | 0.50 |
| Metallic Grey | 10 mm | 16% | 0.29 |
| Clear | 16 mm | 74% | 0.78 |
| Opal | 16 mm | 63% | 0.69 |
Light transmission is the proportion of visible light passing through the sheet. A lower solar heat gain coefficient (SHGC) means less solar heat enters. Colours shown are indicative.
Specification clause
Glazing systems
Aluminium joining bars and matching gaskets accommodate sheet movement as temperatures change.
How the H-Bar system fits together
H-Bar system
Recommended for 10 mm sheets on roofs with a consistent fall. Sheets and gaskets slide into the aluminium H-Bar, which fixes to the supporting rafters.
H-Bar guide (PDF)Flexibar system
For curved applications or alternative sheet gauges. Flexibar requires a supporting rafter with a flat surface, with battens housed into the rafters.
Flexibar guide (PDF)Watch the installation video
See the Thermoclear system being installed. Read the relevant installation PDF alongside the video.
Work out your materials
Plan your Thermoclear installation with Ampelite’s materials calculator and create a product list for quoting.
- Thermoclear sheet quantities
- Joining H-Bars, gaskets and seals
- Fixings and accessories
- Product codes for easy quoting
Warranty & care
Thermoclear is backed by a 10-year limited written warranty covering hail damage and excessive loss of light transmission, subject to its terms and conditions.
Contact your nearest Ampelite office for full warranty details and advice for your application.
Product downloads
Thermoclear brochure
Product range, colours, performance and warranty · PDF
H-Bar installation guide
Design considerations, components and fixing instructions · PDF
Flexibar installation guide
Glazing bar assembly and installation instructions · PDF
Applications in detail
Sheet profiles, accessories and construction details · PDF
Common questions
Can either side face outwards?
Yes. The proprietary UV-resistant surface treatment is applied to both sides of the sheet.
How should sheets be stored and cleaned?
Store flat and protected from sun and rain. Handle carefully to avoid scratching or damaging sheet edges. Ask Ampelite for recommended cleaning products and procedures.
Can silicone sealant be used?
Many silicones are incompatible with polycarbonate and can damage sheets or restrict thermal movement. Use only products confirmed compatible by Ampelite.
Can I walk directly on the sheets?
Never stand or walk directly on the sheeting. Follow the installation guide and use suitable access equipment supported by the structure.
Need help with your project?
Talk to Ampelite about sheet selection, glazing systems and availability.



