Assembling and installing a freestanding greenhouse is one of those tasks that might sound daunting but, with adequate preparation and a logical approach, not to mention a helping hand, we're sure you'll find it a surprisingly uncomplicated and satisfying project.

The most reassuring aspect of the job is that you don't need any special skills, it's handy to know one end of a screwdriver from the other but no technical or complicated DIY skills are demanded. Along with the satisfaction of assembling a highly practical and good looking structure that will be used for many years, you will also have saved a substantial amount of money that would have otherwise been spent on professional installation.

Choose The Location

Before starting to build the greenhouse, you have to choose a level site in a sunny position sheltered from the wind. It's best to locate your greenhouse with the entrance away from the prevailing wind so that the chances are lessened of strong winds blowing through the structure and damaging glazing. The greenhouse will also need a firm foundation made from concrete or slabs - bare soil or grass are not substantial enough.

Construct The Base

For information on whether you need a base and how to create one, refer to our Base Preparation Guide.

Installing a pre-built metal greenhouse base.

Read The Instructions

Check through the instructions so that you are familiar with what is required. You can visualize how everything fits into place, approximately how long it is going to take and how much help you will need. Some instructions may not be immediately clear and it's better to solve any problems before you start so that you don't interrupt the building process or make any time-consuming mistakes.

Check The Parts

First, check that all the necessary parts are present and correct, place them on the ground near to where you are working but far enough away so that they don't get in the way. Various types of crews, nuts and other small items should be put into separate containers so you can readily identify and lay your hands on the correct parts quickly instead of sorting through all of them each time.

Use The Correct Tools

The type and number of tools you'll need will depend on the individual greenhouse and the instructions will always specify which ones you'll need. As a general rule you'll always find that these will be most commonly required:

  • Set of Spanners or adjustable spanner
  • Screwdriver (either ratchet or cordless) and bits
  • Tape Measure
  • Spirit Level
  • Plus gloves and goggles for safety

Start The Build

Instructions will naturally vary between manufacturers and their different greenhouse models. So you should only follow the instructions specific to your particular greenhouse. However, most will advise fitting together the sides parts and ends by laying them on the ground away from the base and connecting the fixings so that they are finger tight. Then, perhaps after fitting the roof and strengthening braces, you transport the structure and fit to the base and foundations. Obviously, you will need help at this point.With the frame in place all the fixings can be fully tightened, constantly checking all the angles are correct and the surfaces level. Unless everything is aligned, fitting the door and glazing correctly and without breakage will be problematic.

Fit The Door And Glazing

If all the elements are aligned and level, the door can be fitted and should open and close smoothly. Any roof vents can be added and then it's time for the glazing, beginning with the roof and then moving onto the sides. Whether the glazing is glass or polycarbonate you will once again need to follow the instructions provided that are specific to the make and model. Some greenhouses will, for example, require the window frame to be de-greased and then a silicone seal added, while others are fitted with a rubber gasket, some greenhouses use clips to fix the glazing in place but others have bar capping.

Once the glazing is in place you can stand back and admire your handiwork and then it's time to think personalising the greenhouse interior with staging, shelving and workbenches together with the many other accessories such as auto vent openers that are available so that your greenhouse becomes a flourishing environment and your horticultural ambitions can be realized.