How to Build a Plastic Shed

Although there are several makes of plastic shed each with specific assembly instructions, there are certain characteristics common to all which are useful to know before you attempt to install your shed.

This guide gives you an insight into how best to build a plastic shed and the tools that are required.

What To Expect In The Box (dependent on make and model):

  • Various Side Panels
  • Roof
  • Door
  • Floor
  • Window
  • Skylight
  • Wall Strengtheners
  • Roof Trusses
  • Fixtures and Fittings

Tools And Other Items You May Need:

  • Cordless Drill & Bits
  • Cordless Screwdriver
  • Mallet
  • Step Ladder
  • Adjustable Pliers
  • Spirit Level
  • Tape Measure
  • Silicone Sealant
  • Gloves
  • Safety Glasses

Laying ConcretePreparations Before You Start

Choose a site where you can work unhindered by any hedges or trees, you must have good access all round the shed.

Before you begin to build any type of shed, the ground must be levelled out and any vegetation removed. If the shed is not level, parts may prove difficult to assemble. Firm foundations are essential, we recommend either paving slabs or concrete. See our guide on How to Build a Concrete Shed Base. Alternatively, there are robust plastic bases available that can be placed directly onto grass or decking.

Read the instructions, twice, and keep referring to them. Some manufacturer's instructions are better than others, they can be a mixture of text and diagrams or just the latter, so it is very easy to make a simple mistake. Another god idea is to check whether there are any instructional films, official or otherwise, on YouTube or else where online. These may not be about assembling exactly the same model but might give you a valuable insight into a particular manufacturer's construction methods. 

If plastic panels are left out in the sun they may expand and be difficult to fit. So, if you have to assemble the shed in hot weather, find some shade where you can leave the panels. On the other hand, cold weather can also adversely affect plastic, so it's best to try and pick a day when the weather is mild and preferably not windy.

Palram Skylight Anthracite 8 x 8 ft Polycarbonate ShedAssembling The Shed

When unpacking the box, make sure that you have all the pieces by cross checking with the instruction manual. It's also a good idea to sort all the screws according to their size into containers so the correct ones are readily accessible.

Normally this is a two person job. The floor is laid first, clipping and/or screwing the panels together. Then the side panels are erected around the edge of the floor, again very simply slipped or popped into place. Inserting a small piece of wood underneath the panels at this stage can be helpful. The panels are further secured using traditional screws or the manufacturer's own bolting system, and then normally strengthened by steel supports.

A window opening may be included in an appropriate wall panel, otherwise one may have to be cut so that a window can be fitted. Once the panels are in place, the doors can be added after any handles, hinges and latches are fitted. Then gables are fixed at each end and secured, any roof bracing and then the roof are added together with a skylight if included.

To prevent condensation forming in the shed, check that all the panels including every screw and washer are fitted correctly so that there is no chance of water entering the shed. You can also use silicone to seal the base rails. Please refer to our guide on How To Prevent Condensation In A Shed for more information.