How To Build A Greenhouse

If having a greenhouse is your dream but you are on a tight budget, buying a high-quality kit and building it yourself could be the solution. Not only will you save on installation costs but also on all the associated expenses, such as preparing the ground and laying foundations. Once you have completed the groundwork, you can order your greenhouse and start building.

Get the site right

Not only will you need to ensure that your site and foundations are totally level but also you will need to pay careful attention to where you site your greenhouse. A south or south-east facing site is best, as the solar gain from putting your greenhouse in the ideal site can save money on heating costs.

Be prepared

Before you start to construct your greenhouse, you will need to check and double check that everything that should be in the kit has been delivered. Next, read the instructions carefully and sort the pieces and fixings according to the diagrams so that everything is to hand. Assemble a basic toolkit, including spanners, screwdrivers, hammers and a spirit level. Finally, enlist the help of a couple of friends, as you can’t build a greenhouse by yourself!

The basic layout

Start by laying out the pieces of the frame and bolting them together, following the instructions to the letter. Gradually piece each section together before securing the basic structure of your greenhouse to your pre-prepared base. Next, add the roof sections, including the roof bars and corner bracings, ensuring that you do not overtighten any section at this stage.

Hang the door

How To Build A Greenhouse

Once the basic structure is erect and stable, you can assemble the door and hang it on the door runners. Slide the door into the runners once complete, then adjust the height of the top runner until the door is operating smoothly. If you have any louvre vents or other means of temperature control, such as automatic windows, you should install these before you start the process of glazing your greenhouse.

Glazed over


There are several options for glazing your greenhouse. These range from inexpensive polyethylene that you stretch over the structure, which is ideal for polytunnels, to tempered glass, which is the most attractive option. Polycarbonate is a savvy choice, as it is much tougher than glass and provides energy savings of around 30 per cent, making it an attractive budget option. To fit your greenhouse glazing, you need to provide a cushion and seal for each pane – do this by fitting foam glazing tape on the bars before sliding the panes into place and checking that everything is level for the snuggest fit. Glaze the roof first, then the wall panes.

Check for level

It is essential that you check for level throughout the build process; otherwise, your glazing won’t fit snugly. Tighten the fastenings gently as you go, giving the bolts a final tighten once you have fitted the glazing. Never over-tighten, as you can crack the glass or even snap the bolts. Once you are satisfied, secure the floor bolts.