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How to assemble a plastic garden storage box

Updated: October 2026

Learning how to assemble a plastic garden storage box starts before the first screw: the base must be flat enough for the doors and lid to meet. These 775–880 litre stores weigh only about 17–22 kg, and their large panels can twist while you work. Check the [plastic tool shed comparison](/hub/tool-accessories/tool-shed-plastic) for the dimensions and listing claims of the Keter Nova, two Olsen & Smith boxes and the Duramax StoreAway. Then follow the manufacturer’s instructions supplied with your exact model. The sequence below covers the recurring UK review lessons without inventing a screw order shared by four different products. A qualifying purchase can earn a commission at no extra cost to you.

Learning how to assemble a plastic garden storage box starts before the first screw: the base must be flat enough for the doors and lid to meet.

Our top picks

Keter Keter Store It Out Nova

Best overall

Keter Keter Store It Out Nova
9.2/10about £137.99
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Duramax Duramax StoreAway 850 L

Alternative

Duramax Duramax StoreAway 850 L
8.6/10about £147.37
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Olsen & Smith Olsen & Smith 775 L shed (80 ratings)

Best value

Olsen & Smith Olsen & Smith 775 L shed (80 ratings)
7.6/10about £109.98
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On this page
  1. 1.Make the base level before opening the panels
  2. 2.Use two people and wait for calm weather
  3. 3.Handle screws and unopened holes carefully
  4. 4.Hold the finished box down

Make the base level before opening the panels

Choose a firm pad that supports the entire plastic floor. Check across the width and depth with a spirit level. Correct a slope before assembly rather than hoping screws will pull the completed box square. An uneven base often appears later as doors that will not meet, a lid that rubs or gaps where rain can enter. The light wall panels follow the floor’s shape; tightening them onto a twist can lock that distortion in. One Duramax review also says the base dipped beneath stacked compost bags, so do not treat the floor as an unstated heavy-load platform. The Amazon 880 kilograms and 41 pounds fields are not tested floor ratings. If the box is intended for bins, the wheelie-bin store guide explains why a 240 litre bin differs from the 120 or 180 litre formats named in these listings.

Use two people and wait for calm weather

Sort the panels and fixings against the parts list before throwing away any packaging. Look for cracks, warped edges and missing hardware while the retailer can still deal with a damaged or incomplete delivery. One Olsen review reports a missing claimed padlock, while isolated Nova feedback mentions a cracked base. Some Nova owners managed alone. That does not make solo assembly the sensible default. A second person can hold a wall upright while you align holes. Choose a calm, mild period. Broad plastic panels act like sails before the box becomes a rigid structure, and Olsen feedback specifically warns against assembly in a breeze. A related Keter Nova manual also calls for two people and advises against windy or cold conditions. It is not proof that every fixing matches ASIN B08XQVQPQ5.
Keter Keter Store It Out Nova

Testsieger

Keter Keter Store It Out Nova
9.2/10about £137.99
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Handle screws and unopened holes carefully

Lay out the supplied screws by size and keep the exact manual visible. UK reviews of the Olsen and Duramax stores mention screws and recommend an electric screwdriver or drill; some also say holes are not fully opened. Do not assume these products simply clip together. Use the manufacturer’s indicated locations rather than drilling a new pattern from a different model’s online video. If a marked hole needs opening, support the panel, use the specified bit. Plastic can strip if a screw is overtightened. Stop if a panel must be forced far out of position, because the cause may be a reversed part or an uneven floor. A gas-assisted lid is claimed on the Olsen listings, but not on the Nova or Duramax data here, so do not transfer hardware assumptions between products. For model selection rather than construction, use the best plastic tool shed guide.

Hold the finished box down

Square the assembled store and confirm that both doors and the lid operate without rubbing. Only then consider anchoring, because fastening a twisted box to the ground will preserve the problem. These products weigh 17.3–21.6 kg empty, and Which? notes that light plastic sheds need anchoring in wind. None of the included-parts information here shows ground stakes. Follow the anchoring instructions for the exact model and the base material. A manual for a related Nova model marks floor positions and says anchoring screws are not supplied, but that should not be turned into a fixing specification for every carton. If you cannot identify the base or safe fixing method, ask a competent installer rather than guessing around buried services. Do not store petrol or gas cylinders inside. For wider pre-purchase checks, read the plastic tool shed buying guide.

Common questions

Do I need two people?
Two people are the sensible choice. Some Nova owners assemble it alone, but a helper keeps broad panels aligned, supports the lid and reduces the risk of wind bending a loose wall. The related Keter manual also specifies two people. Allow more time rather than planning around the fastest review.
What happens if the slabs are not level?
The floor can twist, which changes the relationship between walls, doors and lid. You may see doors that do not meet, rubbing edges or weather gaps. Loosening screws later may not correct a structure anchored on a slope, so level and support the whole footprint before assembly.
Do I need a drill?
Reviews of the Olsen and Duramax stores commonly mention an electric screwdriver or drill, and some say marked holes are not open. Check your exact manual before choosing a bit or making a hole. Drive slowly and avoid overtightening because stripped plastic provides less secure fixing.
Are ground stakes included?
They are not shown in the included-parts information available for these four listings. A related Nova manual says anchoring screws are not included. Inspect the exact carton and manual rather than assuming. Buy fixings suited to both the marked anchor points and your actual base.
Can I build it on a windy day?
Do not. Before the walls and roof are connected, each panel can catch the wind and become hard to control. A helper does not remove that risk. Wait for calmer conditions, keep loose parts weighted safely and follow any temperature limits in the supplied instructions.
Should I add silicone to the base?
Not merely because a generic walk-in-shed guide suggests it. These four products have their own drainage and assembly details, and an unapproved sealant can trap water or complicate a warranty claim. Build to the supplied instructions, keep the base level and address any unexplained leak with the retailer or manufacturer.

Related pages

Plastic shed vs wooden shed

Plastic tool shed

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Plastic tool shed buying guide for UK patio stores

Plastic wheelie bin store: measure bins before you buy

Sources

Public UK sources for planning, bases, security, and consumer rights. amazon.co.uk listings used as captured, with a live check of the Keter Nova on 16 October 2026. Prices move.

  1. Planning Portal, outbuildings (retrieved 16 October 2026)
  2. GPDO 2015, Class E (retrieved 16 October 2026)
  3. GOV.UK, permitted development technical guidance (retrieved 16 October 2026)
  4. Planning Portal, greenhouses and sheds (retrieved 16 October 2026)
  5. mygov.scot, build a shed, garage or greenhouse (retrieved 16 October 2026)
  6. Which?, how to buy a shed (retrieved 16 October 2026)
  7. Consumer Rights Act 2015 (retrieved 16 October 2026)
  8. amazon.co.uk, Keter Store It Out Nova listing (retrieved 16 October 2026)