Multiwall and twinwall polycarbonate sheeting for light transmission and thermal insulation

SUNLITE® UV-protected multiwall and twin wall polycarbonate panels maximize daylighting and thermal insulation in business and industrial buildings. Multiwall polycarbonate sheeting is used for a variety of architectural applications. These include daylight systems, industrial and commercial roofs, curtain walls and facades, commercial canopies and covered walkways, external cladding, interior partitions, illuminated signage, and merchandising displays.

Palram's SUNLITE® range of multiwall polycarbonate products includes SUNLITE® Industrial sheets, SUNLITE® Plus with built-in condensation control for swimming pool covers and greenhouse glazing, and SUNLITE® DIY for residential multiwall roofing.


Palram's SUNLITE® multiwall polycarbonate sheet product range is available in a wide range of colours, thicknesses, and structures.  This range gives you the ability to match the specifications of your application, with the right balance of light transmission, thermal properties, weight, load-bearing, impact resistance, and aesthetics. All SUNLITE® products are suitable both for indoor and outdoor applications.

SUNLITE®  polycarbonate triple wall sheets provide improved thermal insulation, with a more robust structure that performs better under heavier loads.

SUNLITE®  X-lite multiwall polycarbonate sheets, offer unmatched weight-to-strength ratio, along with improved thermal insulation properties. This is SUNLITE’s strongest and thickest version available. This robust multiwall sheet can carry loads better than any other multiwall polycarbonate alternative.

SUNLITE®  7-wall polycarbonate sheets enhance the thermal insulation properties of SUNLITE while retaining low weight and high impact strength. We offer a clear 10mm 7-wall polycarbonate sheet. Requests for thicknesses up to 25mm based on minimum quantities.

SUNLITE®  Plus multiwall polycarbonate greenhouse panels are manufactured with built-in condensation control. It is an excellent choice for greenhouse covers and internal partitions, preserving energy, and reducing condensation accumulation.



SUNLITE® multiwall polycarbonate sheets are produced in a wide range of colours and dimensions. Contact your local office for stock availability.


StructureThickness (mm)Area Weight (Kg/m²)U-Value (W/m²•°K)Width 964 (mm)Width 980 (mm)
Twin Wall101.72.9
7 Wall101.92.3

Note: Other widths & thicknesses are available upon request. Please contact your Palram Distributor for more details.


Product Range

Sunlite® UV2UV protection on both sides
Sunlite® Solar SmartSolar metallic reflective heat blocking sheet

Standard Colour chart

Twin wall 10mm80%35%30%20%
Triple wall 10mm76%




Solar Smart Colours


Solar Colour TextLight Transmission Values Adhere To ASTM D-1003.
StructureSolar IceSolar Control Grey
Twin wall 10mm20%25%

Typical Physical Properties

Heat deflection temperature (HDT)D-648Load: 1.82 MP°C
Service Temperature - Short term°C
-50 to +120
Service Temperature - Long term°C-50 to +100
Coefficient of linear thermal expansionD-696mm/mm °C6.5x10-⁵
Tensile strength at yieldD-63810 mm/minMPa62
Elongation at breakD-63810 mm/min%>90
Impact falling dartISO 6603/1J40-400
Practical thermal expansion/contractionmm/m3

Typical Physical Properties Notes     Physical Properties Data Adheres To ASTM Except Where Noted Otherwise

Flammability Properties


Physical properties data adheres to ASTM except where noted otherwise

BS 476/7Class 1
EN 13501B, s1, d0
ASTM E-84Class A

Flammability Notes      * Depends On Sheet Structure. For More Information Please Contact Your Palram Distributor.


Regulatory Code Compliance Certification

ICC (International Code Council)IBC-2012 (Light Transmitting Plastic)ESR-1893

Use our Engineering Calculators that are customized for Palram products

Frequently Asked Questions

How do I curve the polycarbonate to follow the façade curve?
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All Palram polycarbonate products can be cold bent onsite during installation, subject to a minimum radius. The radius varies based on the chosen product. For flat sheets such as PALSUN & SUNLITE, the rule-of-thumb for the minimum radius is the thickness multiplied by 200. Please check the Palram catalog for more detailed specifications.

How do I specify the required thickness of the polycarbonate glazing material?
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The recommended thickness of the polycarbonate glazing material is based on factors such as wind & snow load, panel size, and boundary conditions. Visit the Palram website for access to calculators that can help you determine the recommended thickness.

How do I reduce the heat build-up coming from the façade into the building?
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In order to reduce heat build-up through the façade, Palram strongly recommends the use of its tinted SolarSmart™ panels. SolarSmart™ tints can be implemented in all Palram polycarbonate products. For more information, reference the Palram SolarSmart™ technology page.

How do I create a double skin glazing solution for façades and curtain walls?
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Flat solid or multiwall sheets can be glazed in double skin applications using standard aluminum curtain wall profiles and EPDM gaskets. The SUNPAL system can be installed in a double skin application with a special aluminum profile provided by Palram.

Should products be pre-dried before thermoforming?
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This depends on the production date and storage conditions of the product before thermoforming. It is recommended to check the product before thermoforming is attempted.

Is the PE film suitable for thermoforming applications?
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Most of Palram's products that are delivered with PE film covering are suitable for thermoforming. In general, we recommend using clear PE and not printed PE.

What is the minimum allowed bending radius of polycarbonate?
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The minimum allowed bending radius of the polycarbonate is 200 times the thickness of the sheet, for example, a 2 mm sheet has a minimum 400 mm bending radius.

Can I use multiwall polycarbonate sheets as a skylight combined with a metal roof?
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Yes, you can by using domes or glazing solutions. Please contact Palram technical support for further information.

How do I install flat solid or multiwall polycarbonate sheets as skylights?
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Flat solid or multiwall polycarbonate sheets need to be installed with designated aluminum profiles when used as a skylight.

Can the percentage of light transmission be controlled? I need a lot of light but I need it to be diffused.
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Palram offers various LT% parameters - from 0% to 90%. In addition, we offer a color called a “diffuser” that allows 85% of the light in while diffusing it by 100%. The result is a light-transmitting panel that is not transparent but is highly translucent.

If polycarbonate sheets block UV radiation, why is there a "UV-side" that faces outwards?
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Polycarbonate sheets block UV radiation by absorbing it. This absorption mechanism can cause degradation to the material, and to prevent this from happening, the sheet is coated with a special material.

For this reason, it is recommended that the sheets are installed with the marked UV protective layer facing outward. Moreover, most of the sheets are only protected on the side that is clearly marked as such.

How do I design the secondary steel support spacings for roofing/siding?
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Palram created specific loading tables for each product. Please visit our website and download the specific catalog.

Can I install multiwall polycarbonate sheets horizontally for siding?
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No. The multiwall channels should always be vertical to allow condensation water to drain out by gravity.

How do I clean the polycarbonate?
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  • Never use abrasive or high alkaline cleaners on any Palram polycarbonate products.
  • Do not leave cleaners on Palram polycarbonate for extended periods of time. Rinse immediately with cold, clean water.
  • Do not apply cleaners in direct sunlight.
  • Never use sharp objects, squeegees or razors on polycarbonate.
  • Do not clean with gasoline.
  • Always practice safety first and never step directly on a polycarbonate panel.
  • Always test cleaners in a small inconspicuous area prior to cleaning the entire panel to ensure against adverse results.
  • Avoid allowing the pressure washer spray tip to come too close to the panel. Pressure washers often have enough pressure at the spray tip to penetrate or tear the panel.
  • Avoid dry cleaning as sand and dust particles clinging to the exterior of the panels may scratch the surface.

What is the meaning of Shading Coefficient (SC)?
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Shading coefficient (SC) is a parameter that compares transparent and translucent materials with clear 3 mm glass with 87% LT ׂ(light transmission). The lower the value, the more convenient it is to stay under the material on warm, sunny days. In architectural projects, the SC should usually be between 0.3 to 0.5.

When should I use multiwall polycarbonate and when solid polycarbonate?
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Multiwall polycarbonate should be used when the key design parameter is thermal insulation. Solid polycarbonate should be used when the key design parameter is acoustic insulation and glass-like appearance.

What is the difference between multiwall and solid polycarbonate?
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Multiwall is a multi-cell structured sheet. Due to its multi-cell structure, it has superior thermal insulation and low area weight.

When should I specify a matte surface finish for the polycarbonate?
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A matte surface finish is good if you want to avoid glare within your surroundings.

How do I determine the color, Light Transmission (LT) and haze properties of polycarbonate?
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This decision depends on the application – some of the colors are transparent and some are translucent. If a see-through material is needed, then haze should be smaller than 1% and the LT% should be based on the illumination design. If a translucent effect is needed, then the haze should be 100% and the LT% based on the chosen color.

Where should I use corrugated versus multiwall polycarbonate covering?
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SUNTUF Plus corrugated polycarbonate sheets provide the best light transmittance and UV light resistance, with exceptional load bearing and impact-resistance properties. SUNLITE Plus multiwall PC sheets provide the best thermal insulation. In locations where you would prefer thermal insulation to light transmission, you should use SUNLITE Plus multiwall PC sheets.

Can I cover my old polyethylene greenhouse with polycarbonate while still keeping the old structure?
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Yes, but with minor reinforcements to the structure in order to support the load.

Will polycarbonate light transmittance deteriorate over time?
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PALRAM's polycarbonate products are shielded with a UV protection layer that guards against photodegradation, yellowing, and brittleness. This protects the sheets from the harmful impact of UV radiation and helps to maintain light transmittance and quality for many years. Our products come with a 10-year warranty against loss of light transmittance. Upon special request, we can provide an enforced UV protection layer with a longer warranty.

Which of Palram's sheets are suitable for printing, sign & display applications?
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For use in illuminated signage, PALSUN, PALSUN CS (Coil Stock) and PALGLAS are suitable for the sign face; and PALBOARD, PALOPAQUE, and PALIGHT for the body of the letters or symbols. For print & display, Palram's entire product portfolio can be used based on the specific application. This choice depends on a combination of several parameters, including the cost of the media, its durability, and its suitability for the specific application. Please visit Palram’s Flat sheet application catalog for more information.

Which materials can be used in the construction of my sign?
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Sign faces are usually made from polycarbonate or acrylic. For extreme conditions such as heavy hail, low temperatures, or high temperatures produced when thermo-forming, polycarbonate is probably more suitable. For sign boxes or channel letter cans, PVC, multi-layered PVC and foam PVC can be used.

Which material diffuses the light better?
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The diffusion is not defined by the material, but by the diffusion additive that is part of the manufacturing formula. The materials should be selected by their fit to the application (e.g. polycarbonate for thermo-forming or extreme weather). Usually products marked with sign grade and/or diffusion grades have greater light diffusion than others.