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Polycarbonate is the perfect material for many roof projects, from conservatories to greenhouses, carports and more. It has the advantage of being lightweight but very tough and provides a low-cost glazing solution that is considered by many to be safer than glass. Of course, it is also cheaper than glass and cannot smash in the same way, which reduces the accident risk making polycarbonate roofing sheets a great roof alternative. It is classed as a thermoplastic, and this means it can absorb heat, giving it the ability to be a first-rate insulator and energy efficient. One of the reasons it is such an excellent alternative to glass for greenhouses, it is very lightweight, making it easy and safe to work with, and once it has exceeded its usable life – which is many years, it can be recycled and reused by melting it down. Polycarbonate roofs do not warp or discolour even in extremely high temperatures making them perfect for roofs of all designs, and it resists UV lights as well. There are so many uses for polycarbonate roof panels that it is no wonder it is so popular.

How to Choose The Right Thickness?

Knowing what thickness of polycarbonate you should use really depends on what you are replacing. If there is already glass or old sheeting, then you should aim to match the thickness. This means that you will get the best fit, and with polycarbonate compared with glass, you also have a much higher impact resistance. The thinner the sheeting, the more light it lets through, but that doesn’t mean the thinnest option could be used. It needs to meet the needs of the project, so the thickness needs to be appropriate for the roof you are replacing, and you have two main choices.

Multiwall Polycarbonate

Multiwall polycarbonate has several layers to create the panel, and this is also what gives it excellent thermal insulation properties; they also have natural acoustic insulation. So if you are looking to cut down the noise from outside and create an inner sanctuary, then multi-wall could be the best solution. It is often used in lean-to buildings and conservatories and comes in many different thicknesses ranging from 4mm to 35mm. It also comes in a range of colour finishes, from clear for projects where the light flow is most important to opal or bronze for an aesthetically pleasing finish.

Solid Polycarbonate

These are single-layer sheets making them incredibly lightweight and very flexible. Think bus shelters and similar structures. It has almost the same light transmission as glass which means around 90% of the sunlight is able to pass through. It can also come in different colours, and the thicknesses range from 2mm to 12mm.

How Thick Should Polycarbonate Roof Panels Be for a Greenhouse?

Obviously, there is a need for greenhouses to heat up nicely in order for seeds to germinate and plants to grow. A small greenhouse can be very successful with 4mm polycarbonate sheets which allow loads of light to come through and offer a safety solution than glass. In a large all-year-round greenhouse, you need to use at least 10mm polycarbonate, and in some cases, 25mm would work better, but this will cut down on light penetration, and a 10mm polycarbonate sheet would be just as good.

What is the Best Type of Polycarbonate for a Greenhouse?

The answer on which sheets you should use is slightly dependent on a couple of factors, including how big the greenhouse is and whether you have twin-wall or multiwall polycarbonate sheets.

How Thick Should Polycarbonate Be for Pergola Roofing?

For a pergola roof, you should be looking at somewhere around 10mm or 16mm polycarbonate roofing. It needs to be able to stand up to weather, and this includes updrafts, as there is usually nothing on the sides of the pergola to stop the wind from getting up and under.

What is the Best Type of Polycarbonate for a Pergola Roof?

The best type of polycarbonate would be either solid or multi-wall, depending on the location, how well protected it is from the elements and whether you want a coloured or plain finish to fit in with the surroundings. How Strong is 2mm Polycarbonate? 2mm polycarbonate is a form of plastic sheet that is almost unbreakable. At this thickness, it is only solid; a multiwall cannot be made this thin. But it is flexible and useful for a range of projects. How Strong is 4mm Polycarbonate? 4mm polycarbonate is considered to be ten times stronger than glass, and even if it breaks, it does not shatter. How Strong is 6mm Polycarbonate? Even though 6mm polycarbonate can be as transparent as glass, it is much more lightweight and has very high impact resistance. How Strong is 10mm Polycarbonate? 10mm polycarbonate is considered to be 300 times stronger than glass How Strong is 16mm Polycarbonate? 16mm sheets are incredibly strong and thick, which makes them perfect for areas that could be prone to accidental damage or vandalism. How Strong is 25mm Polycarbonate? The thickest polycarbonate, 25mm, comes as multiwall and is 200 times stronger than glass when it comes to impact resistance.


The thickness of polycarbonate does depend on several factors, including the project you wish to use it for and the conditions surrounding the structure. We have a vast range of polycarbonate sheets suitable for all projects and are happy to help you work out what is best for your needs, so get in touch with our fantastic team today. 

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