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4mm Polycarbonate Sheets

£0.00 £0.00

4mm twinwall polycarbonate sheets are ideal for greenhouse glazing panels. Whether your are looking for replacement greenhouse sheets or are constructing a new structure, 4mm polycarbonate will offer a great solution. They are also great for cloches and cold frames. 4mm polycarbonate is a lightweight and safe to handle alternative to glass. The fluted structure offers thermal insulation. High impact resistant and excellent value for money.

We cut it to size for you completely free of charge.  However, if you need to adjust the sheets on site they are easy to cut on site.

Available Colours: Clear

 Please input the length and width you need below.

Availability: In stock



4mm Twinwall Polycarbonate Sheets

Mainly used for Greenhouse glazing, 4mm polycarbonate sheets are a lightweight and safer to handle alternative to glass. The sheets are manufactured from damage-resistant polycarbonate and have fine optical clarity. They also have co-extruded long life protection from the effects of UV rays. The high performance UV absorption layer means longer life. This is shown in prevention of yellowing and loss of strength. Polycarbonate offers excellent protection against vandalism and accidental damage. It has an impact resistance up to 200 times greater than glass. This is maintained over a broad temperature range and long service life. Whether you are replacing broken panes in your greenhouse or increasing the level of insulation, 4mm twin wall polycarbonate is the perfect choice.

Main Benefits

       . High levels of natural light
       . Light weight and very easy to handle
       . High optical clarity
       . Thermally insulating
    . Damage and impact resistance
    . Weatherable Longlife UV protection
    . Fire resistance - Class 1 surface spread of flame when tested to BS476 Part 7.       
    . 10 year warranty
    . Perfect for replacing greenhouse sheets


       . Greenhouses

       . Vertical, Secondary and Internal Glazing



Tints: Clear

Technical Information

4mm Polycarbonate Sheet Thickness
U-Value 3.8
Light Transmission 82%
Weight (kg per sqm) 0.8 


Frequently Asked questions

Which way up does my polycarbonate sheeting go?

Polycarbonate sheets are delivered with a peel off protective film covering both sides. The top side of the sheet has co-extruded (built in) UV protection so the sheet must be installed the right way up. Usually only one side of the sheet will have writing on the protective film. That indicates that it is the top of the sheet and the roof sheet should be fitted with that side facing the sky. If there is writing on both sides look for the one that says 'this side up'.

Are the ends of the sheets taped?

The open ends of the 4mm polycarbonate sheets are not taped. 

Which is the length and which is the width of a sheet?

The length follows the lines of the flutes down the sheet and the width is across them.


More information about all of the thicknesses of structured polycarbonate, their colours, applications and prices can be found in our polycarbonate sheets pages. Alternatively check out our Polycarbonate Buyers guide.


Should you have any questions or need any help at all please call us on 01536 446395 and we will be very happy to help you.