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Metal vs plastic garden shed

Updated: 22 October 2026

The listing says water resistant, or waterproof, and you still have to choose between a thin steel shell and a resin box that will not rust. Metal vs plastic garden shed is that trade, plus the exits in this amazon.co.uk set: a fir cabinet, and four fabric tents if you only need a season of cover. The waterproof line does not settle rust, condensation, security or wind. Prices are the listings on 19 October 2026, read by the Products Compared editorial team. Seller guides are labelled as theirs. Nothing here is a lab test. The twelve rows stay on the [garden shed comparison](/hub/garden-supplies/garden-shed).

The listing says water resistant, or waterproof, and you still have to choose between a thin steel shell and a resin box that will not rust.

Our top picks

Keter Keter Store It Out Nova

Best overall

Keter Keter Store It Out Nova
9.2/10about £137.99
View offer
EPCPSHADES EPCPSHADES steel-frame bike tent

Best value

EPCPSHADES EPCPSHADES steel-frame bike tent
6.8/10about £51.99
View offer
COZYBRITE COZYBRITE 6 x 4 metal shed

Rank 3

COZYBRITE COZYBRITE 6 x 4 metal shed
5.7/10about £149.99
View offer
On this page
  1. 1.What the two metal listings actually are
  2. 2.What the resin listings actually are
  3. 3.Condensation, rust and a padlock
  4. 4.When wood or a tent wins

What the two metal listings actually are

The steel sheds here are the COZYBRITE, listed at £149.99, and the Garden Universe pent, listed at £169.99. COZYBRITE measures 170.5 cm wide, 110.5 cm deep and 178 cm high. Garden Universe is 195 x 118 x 183 cm, with sliding doors listed at 60 x 158 cm. Both say water resistant, and neither page gives a test figure. A COZYBRITE reviewer describes the roof-edge sheet as about 1 mm. Neither has a solid floor in the reviews. Buyers found struts on the COZYBRITE, and no base to fix on the Garden Universe. Six Garden Universe reviews average 2.8 and mention two days or a paid builder. An empty COZYBRITE was liftable by two people. ShedBuilder puts typical 8x6 metal at about £300 to £1,400 and at high security. These two sit below that band. Do not paste that rank onto a light sheet at about £150.

What the resin listings actually are

Plastic here means resin or polypropylene. The boxes are the Keter Store It Out Nova, at £137.99 with 4.4 from 15,025 reviews, and the Olsen & Smith 775 litre box, at £109.98, which includes a padlock and has panels reviewers call very thin. You do not walk into either. The LARBANKE 4 x 6, at £339.99, claims a floor, at 3.9 from 13 reviews. The 8x6 pages sit near 2.8 and 2.9 from a handful of reviews, and one buyer measured about 5 ft 3 in inside. Resin will not rust. It is not automatically easier to build. The screw order is on how to assemble a garden shed.
Keter Keter Store It Out Nova

Testsieger

Keter Keter Store It Out Nova
9.2/10about £137.99
View offer

Condensation, rust and a padlock

A wet steel ceiling is often condensation. Norfolk Sheds, a seller, describes metal sweating on a cold roof. GardenSite says keep a membrane in the slab, and do not use tarmac where anchors must bite. A resin wall conducts that night cold less readily. Vents will not make a thin metal shed feel like a workshop. Resin does not rust, and it does not rot the way untreated fir does. ShedBuilder ranks a heavy mid-range metal shed as harder to cut quietly than plastic. A COZYBRITE with latch screws on the outside is not that shed: a reviewer notes the screws can be undone. Olsen includes a padlock, on thin panels. A resin hasp is not a safe. Anchor both until the bolts are in concrete.

When wood or a tent wins

Choose the Outsunny fir cabinet, listed at £137, when the gap is about 46.5 cm and you will treat the timber. It is not a walk-in. Two of 39 reviews say the inside stayed dry after staining. The fir splits at the lock. Choose a fabric tent for a temporary cover of about two bikes. EPCPSHADES, at £51.99 with 4.1 from 120 reviews, has no floor, and pegs fail unless you weight them. PMEIXU at £129.99 is 220 cm tall, and reviews report two bikes rather than four or five. Choose the LARBANKE 4x6 if you want a claimed resin floor, the COZYBRITE if you will build your own floor, and the Keter box if you will not walk inside. Size stays on the garden shed buying guide. Named picks sit on best garden shed.

Common questions

Should I buy metal or plastic?
Buy resin if you want a material that will not rust and, here, a LARBANKE floor you did not build, and you will anchor it. Buy the COZYBRITE if you accept condensation, struts instead of a floor, and screws on the outside of the latch. Do not buy either from the word waterproof.
Why is the inside of a steel shed wet?
Condensation forms when damp air meets a cold metal roof. Norfolk Sheds calls that sweating, separate from a failed joint. GardenSite's advice is a membrane in the slab and no tarmac under the anchors. A wet patch at a screw line can still be a leak.
Which is harder to break into?
A heavy mid-range metal shed can be harder to cut quietly than plastic, which is how ShedBuilder ranks typical sheds. These two metal listings are lighter than that picture. COZYBRITE hinge screws are on the outside, so a padlock does not hold the door if the screws come out.
Will resin rust or rot?
Resin and the polypropylene on the Olsen box do not rust, and they do not rot as bare timber does. They can flex, chalk and crack. Steel rusts where the coating is scratched. No listing here publishes a proven lifespan in years.
What about the wooden cabinet?
The Outsunny is a cabinet 46.5 cm wide, not a walk-in shed. It suits a narrow gap if you stain it and accept soft fir that can split at the lock. The roof is stated for light or medium rain.
When is a fabric tent the honest answer?
A tent is the honest answer for a short-term cover for about two bikes in a sheltered spot, if you will tie the frame down or weight the feet. It is the wrong answer for winter security or a solid floor. Pegs alone pull out of a wet lawn.

Related pages

Plastic garden shed comparison

Garden shed

Garden shed planning permission, height and the base

Best garden shed for bins, bikes or a walk-in store

Garden shed buying guide: size before the 6x4 label

How to assemble a garden shed without twisted doors

Sources

Public UK sources for this comparison. Prices, stars and review counts are the amazon.co.uk listings in this set, dated 19 October 2026. Page updated 22 October 2026.

  1. Planning Portal: outbuildings (retrieved 22 October 2026)
  2. GPDO 2015, Class E (retrieved 22 October 2026)
  3. GOV.UK: permitted development technical guidance (retrieved 22 October 2026)
  4. Building Regulations 2010, Schedule 2, Class 6 (retrieved 22 October 2026)
  5. Building Regulations 2010, regulation 9 (retrieved 22 October 2026)
  6. Scottish Government: Circular 1/2024, Class 3A (retrieved 22 October 2026)
  7. ABI: buildings insurance (retrieved 22 October 2026)
  8. BIBA: garden insurance (retrieved 22 October 2026)