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DIY Step Image - How to build a greenhouse . Blob storage upload.

Overview

A greenhouse gives your plants every chance to thrive while protecting them from harsh weather.

Steps

1Pre-cut the timber to size

To make this project easier, you can get all of your timber pre-cut at your local Bunnings. A good tip is to group and label the timber lengths together for each side so you know where it will be used. You can make your greenhouse any size you like, here's the cutting list we used:

200mm x 50mm pine:

  • 1500mm x 2
  • 1200mm x 2

70mm x 35mm pine:

  • 1600mm x 7
  • 1500mm x 2
  • 1200mm x 6
  • 1150mm x 11
  • 1140mm x 2
  • 1070mm x 1
  • 670mm x 1
  • 315mm x 3
  • 1030mm x 4

1500mm x 90mm treated pine decking boards x 9 (floorboards)

1600mm x 70mm x 45mm treated pine x 1 (roof batten)

1600mm x 70mm x 35mm treated pine x 1 (roof batten)

1600mm x 50mm x 25mm rough header x 1 (roof batten)

DIY Step Image - How to build a greenhouse . Blob storage upload.

2Make the floor frame

Take the four 1600mm x 1200mm hardwood sleepers and make a rectangle with them. Make sure the edges are flush and then pre-drill holes with the 5mm drill bit. Fix the frame together with 125mm bugle screws.

DIY Step Image - How to build a greenhouse . Blob storage upload.

3Attach the subfloor

Place the 1500mm x 50mm x 2 lengths and 1200mm x 50mm x 2 lengths for the subfloor on the inside of the floor frame. Then attach them to the floor frame with the fixing gun. You should also add two joists an equal distance apart and use the nail gun to secure them down for extra support.

DIY Step Image - How to build a greenhouse . Blob storage upload.

4Attach the caster wheels

Turn the frame over. Use the 125mm bugle screws to attach the caster wheels in each corner of the frame. There's no need to pre-drill, just screw them straight in. A good tip is to put the two casters with stoppers on diagonal corners.
DIY Step Image - How to build a greenhouse . Blob storage upload.

5Attach the flooring

Secure the first piece of timber flooring rib side down and flush with the edge. Then use a timber offcut as a spacer and lay the next length down. Secure it with the fixing gun, and repeat this process until you've finished the floor. These gaps in the floor will help you with drainage.
DIY Step Image - How to build a greenhouse . Blob storage upload.

6Build the front frame

Make a rectangular frame with the 2 x 1600mm lengths and 2 x 1150mm lengths of timber. Join them together with the framing gun. 

7Measure for the studs

Once you've worked out how big you want the greenhouse door to be, measure and mark where the studs will go. Remember to take into account the width of the third stud to attach the door hinge to.

DIY Step Image - How to build a greenhouse . Blob storage upload.

8Secure the studs

Use the fixing gun to secure the three studs.

DIY Step Image - How to build a greenhouse . Blob storage upload.

9Make the door

Lay out the frame for the door with the 2 x 670mm lengths, 2 x 1140mm lengths, 1 x 1070mm length for the centre and 3 x 315mm lengths for the noggins. Before fixing with a framing gun, be sure the timber is flush to the frame.

DIY Step Image - How to build a greenhouse . Blob storage upload.

10Build the back and side frames

Now it's time to repeat the previous steps to build the back and side frames for the greenhouse. Note that you won't have to include the door in the frames.

DIY Step Image - How to build a greenhouse . Blob storage upload.

11Attach the plastic

Now that you've made your frames it's time to wrap them in plastic. Make the plastic as tight as possible and fix with a hammer and the foil fixers. Trim any excess plastic with a utility knife. A good tip is to attach the fixers to the inside of the frame so that the finished greenhouse looks neat. You'll need to repeat this process for each of the four frames.

DIY Step Image - How to build a greenhouse . Blob storage upload.

12Attach the hinges and bolt to the door

Screw the hinges into the side studs. You'll find the screws for this in the pack with the 200mm hinges. Then attach the bolt. Screw the bracket into the noggin and the pad bolt to the door. 

DIY Step Image - How to build a greenhouse . Blob storage upload.

13Attach the frames to the base

You'll need someone to help you with this step. Attach the sides, back and front to the base frame and to each other using the 125mm bugle screws. Make sure all of the frames are flush with the edges of the base and the other frames before securing.

 

DIY Step Image - How to build a greenhouse . Blob storage upload.

14Attach the roof battens

You'll need a slight fall on the roof, so attach the timber battens with different widths in descending order. Starting at the front, secure the 70mm x 45mm x 1600mm batten, then the 70mm x 35mm x 1600mm batten and then the 50mm x 25mm rough header.

DIY Step Image - How to build a greenhouse . Blob storage upload.

15Measure and mark for your polycarbonate

Measure the length of the roof for the greenhouse. Allow a little extra overhang at the front and back for runoff. Transfer these measurements onto the polycarbonate. Mark the line with masking tape because this helps ensure a clean, straight cut.

DIY Step Image - How to build a greenhouse . Blob storage upload.

16Cut the polycarbonate roof

Clamp the polycarbonate to the top of the greenhouse to make sure it doesn't move so you get a smooth, straight cut. When cutting, use the jigsaw with a metal blade on the medium setting, and don't forget to wear the appropriate safety gear when cutting.

DIY Step Image - How to build a greenhouse . Blob storage upload.

17Attach the roof

Attach the polycarbonate roofing to the greenhouse using roof screws. You should screw them into every second crest of the corrugate for a secure roof. 

DIY Step Image - How to build a greenhouse . Blob storage upload.

18Position and fill your greenhouse

Now all you have to do is roll your greenery into the right location and fill it with your favourite plants.
DIY Step Image - How to build a greenhouse . Blob storage upload.

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More D.I.Y. Advice

Health & Safety

Asbestos, lead-based paints and copper chromium arsenic (CCA) treated timber are health hazards you need to look out for when renovating older homes. These substances can easily be disturbed when renovating and exposure to them can cause a range of life-threatening diseases and conditions including cancer. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer or visit our Health & Safety page.

When following our advice in our D.I.Y. videos, make sure you use all equipment, including PPE, safely by following the manufacturer’s instructions. Check that the equipment is suitable for the task and that PPE fits properly. If you are unsure, hire an expert to do the job or talk to a Bunnings Team Member.