A greenhouse is a must in many gardens. Its controlled environment can not only enable you to grow exotic plants that wouldn’t survive outside, but will also either protect plants from frost or to bring on others early.
It needs to be carefully constructed to be effective, though. If you’re not confident about building a greenhouse in London, Handy Squad can put it up expertly, but if you decide to tackle it yourself, there are several things to remember.
What You Need
You can buy various sizes of ready-to-assemble greenhouses, with either timber or aluminium frames — the latter is easier to manage. It’s generally advisable, though not essential, to also buy a galvanised steel base.
Your glazing can be horticultural glass, toughened glass or polycarbonate panels. Horticultural glass shatters fairly easily and may be unwise if you have children. The glazing should have adjustable vents, so you can control ventilation.
Make sure you have room to get all the way round your greenhouse, and lay concrete or paved paths, both inside and outside, before you erect the structure.
Laying the Base
If you’re using a steel base, there are three ways of fixing it securely — small pockets of concrete with hooks embedded; bolting it to a concrete footing strip 200mm wide by 100mm deep; or fixing it to a course of bricks on the concrete footing. If you’re not using a base, you can attach the frame to whatever footing you use, but you may need wooden battens in between.
Using bricks is generally recommended. After checking the base kit to make sure everything’s there, assemble it according to the manufacturer’s instructions and lay it on the ground where you want the greenhouse. Mark it with two parallel builder’s lines, one 50mm from the outside, the other 150mm from the inside.
Dig out the trench and fill it with concrete, ensuring the top is perfectly level. When it’s completely dry, lay the base on it and draw a pencil line around its outer edge. Lay a single course of bricks around the centre of the concrete and give the mortar 24 hours to dry, then lift the base onto the bricks.
Building the Greenhouse
Lay out the pieces for each gable in turn on a flat surface, making sure everything’s the right way round, and bolt them loosely into place. Then follow the same procedure for each side and loosely bolt the four pieces together before screwing the frame loosely to the base.
Screw the roof ridge loosely between the two ends and attach the roof vent fittings before screwing in the roof glazing bars. Check with a spirit level that it’s completely level, then tighten all bolts and screws and drill 25mm frame fittings through the base into the brick course.
Assemble and screw the roof vent and slide it into place, then push the rubber line into the slots around the frame. Fit the glass from the roof down, securing each pane with clips. You’ll need to wear goggles and gloves for this, and work patiently, making sure each pane is right. Finally, assemble the door, including its glass, and slide it into place.
Think About a Professional
If you’re confident about building your greenhouse, well and good, but it may be better to get a professional in rather than ending up with a wonky and inefficient greenhouse. Handy Squad’s handymen can put up any type of greenhouse to the highest standard.