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Polycarbonate sheet buying guide

Updated: 23 October 2026

A cracked greenhouse pane, a shed window, and a lean-to roof are different jobs, and a star rating will not tell them apart. This polycarbonate sheet buying guide puts the opening first: solid or twin-wall, then a thickness that suits the span, then what the four amazon.co.uk listings in our [polycarbonate sheet comparison](/hub/diy-supplies/polycarbonate-sheet) can actually cover. If the sheet has to carry a roof span, you may need to leave this set entirely. We read those listings and UK merchant guidance, updated this page on 22 October 2026, and did not run a lab test. A qualifying purchase can earn us a commission at no extra cost to you.

A cracked greenhouse pane, a shed window, and a lean-to roof are different jobs, and a star rating will not tell them apart.

Our top picks

Panda Ant Panda Ant 4 mm solid sheet

Best overall

Panda Ant Panda Ant 4 mm solid sheet
7.6/10about £24.99
View offer
CHEOAR CHEOAR 4 mm twin-wall 10-pack

Best value

CHEOAR CHEOAR 4 mm twin-wall 10-pack
7.4/10about £61.99
View offer
SANJIAOJIA SANJIAOJIA sheet, 1 m × 2 m

Alternative

SANJIAOJIA SANJIAOJIA sheet, 1 m × 2 m
5.5/10about £32.90
View offer
On this page
  1. 1.Start with the job, not the star rating
  2. 2.Thickness in millimetres
  3. 3.What the four listings can and cannot do
  4. 4.Rules that change the buy

Start with the job, not the star rating

Name the opening before you name a brand. A single glass-sized hole wants a flat solid pane. A run of hobby-greenhouse sides wants twin-wall, because the flutes add a little insulation. A canopy or lean-to wants thicker multiwall on a bar system. Solid sheet is one clear layer. Twin-wall is two skins with ribs, so you must keep water out of the channels. A thin roll that will not lie flat is not a cheap window. The Glazing Shop treats 4 mm and 6 mm twin-wall as greenhouse glazing, and 10 mm as the start of canopy work. The 4 mm versus 6 mm choice is on our polycarbonate sheets for a greenhouse page.

Thickness in millimetres

Thickness is the span, not a quality badge. On The Glazing Shop's figures, 4 mm twin-wall is about 82% light with a U-value of 3.8 W/m²K, and 6 mm is about 80% with 3.5 W/m²K. Those figures are that merchant's. Their buyers' guide puts 10 mm twin-wall at about 600 mm between supports, and longer spans only at 16 mm and above. Nothing in this amazon.co.uk set is a 10 mm or 16 mm roofing sheet. The Polycarbonate Store, as trade context rather than a price we are ranking, lists 4 mm twin-wall at £17.57 per square metre and 10 mm at £16.94 per square metre. Our set stops at 4 mm, plus two rolls that are thinner still.
Panda Ant Panda Ant 4 mm solid sheet

Testsieger

Panda Ant Panda Ant 4 mm solid sheet
7.6/10about £24.99
View offer

What the four listings can and cannot do

Read the four listings as three products. The solid pane is 610 mm by 457 mm by 4 mm, at £24.99, manufacturer field Exolon, six ratings at 5.0. Skip it if you need flutes or more than one pane. The twin-wall 10-pack is £61.99, about 61 cm by 121 cm by 4 mm, 4.9 from 23 reviews, brand field Generic, and no fixings in the box. The other two listings are thin SANJIAOJIA rolls, about 1 mm. Reviewers describe curl and a sheet too thin for a shed window. If the title says Perspex or acrylic, you are on a different polymer. Buying the sheets does not by itself trigger a planning application.

Rules that change the buy

Outdoor multiwall is coated on one face, and that face goes to the sun. If the protective film has no UV print, you cannot tell the coated side by eye. End tapes are part of the system: closed tape at the top, breather tape at the bottom. The CHEOAR pack's included-components field is NO, so those tapes are a second purchase. Ask for a BS EN 16153 mark if you are buying multiwall as a specified roofing sheet. Do not assume the mark on a Generic amazon.co.uk pack. Approved Document B treats solid polycarbonate of at least 3 mm as TP(a) where that route applies. That does not transfer to an untested multiwall pack or a 1 mm roll. The fitting sequence is on how to fit a polycarbonate sheet.

Common questions

What thickness polycarbonate sheet should I buy?
Match thickness to the opening and the support spacing. For a typical UK hobby greenhouse, merchants start at 4 mm twin-wall and treat 6 mm as the next step. For a lean-to, Professional Building Supplies points to 10 mm or 16 mm, and The Glazing Shop warns against 4 mm as a conservatory roof. This set has no sheet thicker than 4 mm, so a wider span means a trade board.
Is 4 mm twin-wall enough for a roof?
It is enough for many greenhouse sides and for short, well-supported spans. It is not enough for a conservatory roof or an unsupported lean-to. The Glazing Shop's buyers' guide puts 10 mm twin-wall at about 600 mm between supports, and longer spans only with 16 mm and above.
What is the difference between solid and twin-wall polycarbonate?
Solid sheet is one clear layer, so it suits a single rebate where you want a flat view, such as a 610 mm by 457 mm greenhouse pane. Twin-wall is two skins with ribs, so it insulates a little better and shows a line pattern. You have to tape the ends or the flutes fill with dirt and algae. A thin roll is neither of those products.
How much do polycarbonate sheets cost on amazon.co.uk?
In this comparison the entry band is about £16 to £25 and the mid band is about £33 to £62. The solid 4 mm pane is £24.99. The 4 mm twin-wall 10-pack is £61.99. Trade 4 mm at The Polycarbonate Store is £17.57 per square metre, which is a different buy from a small cut pane or a pack with no tapes.
Does a high star rating mean a fire rating?
No. Stars on these listings record fit, apparent thickness, and whether a roll would lie flat. They are not a BS EN 16153 certificate and not a fire classification. Solid polycarbonate of at least 3 mm can sit in the TP(a) route under Approved Document B, but that does not transfer to a Generic multiwall pack or a 1 mm roll.
How do I tell polycarbonate from acrylic before I pay?
Read the material field and the title, not the word clear. Perspex and Plexiglass are acrylic names. Polycarbonate is the tougher sheet, and the one to use where the pane may be hit or where it is a greenhouse roof. Acrylic is clearer and harder at the surface, and it is more likely to crack. If the listing only says Plastic, treat that as incomplete and do not assume the polymer.

Related pages

Best polycarbonate sheet

Polycarbonate sheet vs acrylic

Polycarbonate sheet

Polycarbonate sheets for a greenhouse: 4 mm or 6 mm

How to fit polycarbonate sheet without standing on it

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Listings captured 19 October 2026. Updated 23 October 2026.

  1. The Glazing Shop thickness guide (retrieved 19 October 2026)
  2. The Glazing Shop buyers guide (retrieved 19 October 2026)
  3. BSI, BS EN 16153:2013+A1:2015 (retrieved 19 October 2026)
  4. Approved Document B amendments (retrieved 19 October 2026)
  5. Brett Martin TB413 (retrieved 19 October 2026)
  6. Brett Martin Marlon ST (retrieved 19 October 2026)
  7. RHS: choosing greenhouses (retrieved 19 October 2026)
  8. Class E, GPDO 2015 (retrieved 19 October 2026)
  9. The Polycarbonate Store twin-wall (retrieved 19 October 2026)