Easy steps to build your own green house
Gather your supplies
- Recycled timber of various sizes
- Treated pine sleepers (optional)
- Recycled windows and doors
- Polycarbonate roof sheeting and ridge capping
- Recycled shadecloth
You'll also need
Post stirrups; drill; 10mm masonry drill bit; 10mm masonry anchors; spirit level; hex head bolts; clamp; 100mm batten screws for treated pine; easy-fit hinges; circular saw; stringline; angle grinder fitted with a metal cutting blade or tin snips; polycarbonate roofing screws; construction adhesive; nail gun and nails; shadecloth clips
For you to note
Check with your local council for restrictions on the size and position of your greenhouse.
If demolishing an existing structure, keep as much as you can for use in your new greenhouse.
Draw a plan of your greenhouse with sizes of windows, doors and framing timber all worked out. Leave a gap of around 5mm around windows and 10mm for doors. This will determine where your posts go.
At the post positions, fix stirrups to concrete. Predrill using a 10mm masonry bit and attach using masonry anchors. In areas without concrete, lay a row of timber sleepers on edge to act as the foundation.
Sit posts in stirrups, make plumb and brace. Mark a level line around all posts then cut to length. Bolt posts in the stirrups.
Construct wall frames as per your plan. If using timbers of different sizes, make 1 side of the frame flush.
Place frames between posts and clamp to hold. Check for plumb then screw frames to posts with batten screws. Screw frames together where they meet.
Predrill and fix bottom of frames to concrete or sleepers.
Lift windows into gaps in frames. Use a block of timber to make sure they are even to the frame then screw in place.
Attach easy-fit hinges to doors then screw into frame. At top of the opening, nail a strip of timber to act as a stopper for the doors when they close.
Prop ridge and brace above centre of end walls. Here the ridge is 700mm above the walls.
Cut rafters to run from the ridge board down to the support walls. At top of rafter make a plumb cut so it sits flat against the ridge board. Where the rafter crosses the walls, make a cut known as a bird’s mouth. This is a small cut in the bottom of the rafter so it will nestle in the outside corner of the wall plate and sit flat. Once you have cut a rafter that fits, use it as template to mark out and cut a few more rafters.
Mark out top of wall plate and side of ridge with rafter positions. Mark side of rafter on plate then an X on the side of the line where the rafter will sit. Here the rafters are 450mm apart under the roofing and 900mm apart under the shade cloth.
Starting at 1 end, place rafters in position and nail to ridge and top plate of wall. Stretch a stringline along the top of the ridge to make sure it is straight as you nail.
Cut and nail blocking to fit between joists where roofing will sit so you have something to screw into.
Cut polycarbonate roofing to length using an angle grinder fitted with a metal cutting blade or tin snips.
Sit roofing on rafters with the cut edge at the top. Screw sheets to rafters using polycarbonate roofing screws. Make sure your sheets are square to the roof before fixing. Screw ridge capping over the sheets at top of the roof.
Spread construction adhesive along timber frame where lining boards will sit. Nail first board in place, making sure it is level.
Continue gluing and nailing lining boards to the frame. Cut boards around windows. Where you need to join boards along their length, make the join sit over a wall stud.
Stretch recycled shadecloth over the rest of the roof of the greenhouse and hold in place using shadecloth clips.
That's it! Enjoy your new greenhouse
Now, just add plants
1. Repurpose an old ladder
Turn your old wooden stepladder that wobbles too much into a shelving system for unused pots. It has beautiful symmetry and its weathered appearance gives it character.
2. Create a place to chill-out
A built-in bench seat on the outside wall of your shed is a top place to take a gardening break. For an instant vertical garden, attach climbing screens to support posts with hinges on the outside and locking latches on the inside, then hang pots of mistletoe cactus (rhipsalis sp.) from the wire.
3. Create a vignette
A Swiss cheese plant (Monstera deliciosa) and a Boston fern (Nephrolepsis exaltata) are decorative. That big ball of twine is essential!
4. Have it both ways
You can hang plants on both sides of the climbing screens, those that want shade on the inside and sun-lovers on the outside.
5. Just about anything can be repurposed
Don't throw out the old hand basin when renovating your bathroom. It comes with an ideal-sized drainage hole, and a sink makes a snug home for succulents.
Plants to try
Fill your greenhouse with these fabulous exotic plants!
1. Smell sensation
Take in the wonderful aromas of true cardamom (Elettaria cardamomum).
2. Forever frilly
The leaves of coral bells (Heuchera sp.) are a standout feature.
3. Smart choice
Dumb canes (Dieffenbachia sp.) grow in both light and shade.
You can get Chinese evergreen (Aglaonema sp.) in green, yellow, red or mixes of colours.
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