Multiwall Polycarbonate comes in a range of sheet thicknesses, internal wall profiles and colours or tints. Different sheet thicknesses have different levels of light transmission, insulation properties and acoustic levels. So which one do I need for my own project?

Luckily the answer is not that complicated, some multiwall polycarbonate sheets lend themselves to certain applications while being totally unsuitable for others. For example nobody would consider putting 35mm Polycarbonate in a greenhouse or cloche just as using 4mm twinwall polycarbonate in a conservatory roof would be impractical.

Different polycarbonate sheet thicknesses lend themselves to different applications:

4mm Polycarbonate Sheets

4mm Twinwall Polycarbonate sheeting is most commonly used for replacement Greenhouse Glazing. It is very light weight (0.8kg / sq. metre) and unlike 4mm glass it is safe and easy to handle. Other horticultural uses for 4mm Polycarbonate include cloche and cold frame glazing.  Light transmission is high at 82% and clear 4mm polycarbonate has a U Value of 3.8 W/m2. 4mm can also be used for handy internal drawer and cupboard dividers!

6mm Polycarbonate Sheets

6mm Twinwall Polycarbonate sheeting is also used for replacement Greenhouse Glazing. 6mm Polycarbonate is easy and safe to handle and has good heat retention properties (U-value 3.5W/m2). It is also used internally for displays and vertical glazing in the form of space dividers. The ability to cold form into a curve is useful in internal design. Light transmission is high at 80%

10mm Polycarbonate Sheets

10mm Twinwall Polycarbonate sheet is good for all-round use.  It is very popular for both new and refurbished Canopies and Carports. 10mm Polycarbonate sheeting offers high strength and is light weight (1.7kg/m2) and easy to handle, making work at height much safer. Used regularly to update and repair corrugated roofs on canopies and carports 10mm is durable, value for money and long lasting.

16mm Polycarbonate Sheets

16mm Triplewall Polycarbonate sheet is the standard sheet used for Canopies, Car Ports and Lean To roofs. Its three walls make it stronger than 10mm sheet and allows for greater spacing between supports. The additional wall also helps to dampen the noise of rainfall. Co-extruded with a UV inhibitor on the top of the sheet the 16mm Polycarbonate sheeting comes with a 10 year guarantee and gives good light transmission (76% for clear, 48% for Opal and 35% for Bronze.)

25mm Polycarbonate Sheets

25mm Polycarbonate Sheets have an X structure profile of internal walls that provide superior insulation and acoustic qualities. 25mm polycarbonate is the standard material used on most conservatories because it allows for good light transmission as well as heat retention. (Light Transmission: 62% for Clear, 20% for Opal and 15% for Bronze). 25mm polycarbonate is also used in commercial applications such as industrial rooflights as well as swimming pool covers and covered walkways.

32mm and 35mm Polycarbonate Sheeting

32mm and 35mm Polycarbonate sheeting have an internal construction made up of 7 walls giving them highly impressive insulating characteristics. 35mm was created specifically for conservatory roofs and provided an update for the older 32mm design. It can provide good energy savings and is much safer to install than glass units. 32mm and 35mm Polycarbonate also have excellent fire performance data and are used widely in commercial applications such as factory rooflights and in agricultural settings where insulation and light transmission are important, such as chicken sheds. 32mm Polycarbonate Sheeting is 3.6kg/m2 while 35mm is 3.9kg/m2 which means it is still easier to handle than glass during installation.

Colour Options

4mm and 6mm Polycarbonate Sheets are only available in clear but the other sizes of polycarbonate are available in Clear, Opal or Bronze tints. Where you want to maximise the light such as in a greenhouse then clear is the best option. It you want to let light in but want to hide any dirt or debris that may appear on the roof then Opal is a good option. Bronze polycarbonate tends to be used where you have a timber lean to or a brown canopy and want the polycarbonate colour to match. Please note that the different colours have different levels of light transmission, click on the individual polycarbonate pages for further details.

25mm, 32mm and 35mm Polycarbonate sheets have an extra option for dual tints. Available in a Bronze Opal colouring and Heatguard Opal. The bronze / opal sheet has a Bronze tinted exterior with an Opal interior and tends to be used where people want the exterior of the polycarbonate to match say their brown windows but want the inside to be lighter coloured to match their internal décor and bounce light around.

Heatguard Polycarbonate has a more silvery grey external surface that helps to reduce heat absorption through the polycarbonate sheet. It is used to reduce heat build up in say a conservatory. The internal Opal colour makes the most of internal light.


If you need any more help or information, please don't hesitate to call us on 01536 446395, we are here to help!