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Transform your backyard with a low-level deck

Outdoor entertaining area with timber deck, potted greenery, and hanging plants beneath a covered roof

Overview

There’s no end to timber decking ideas out there but sometimes your outdoor renovation is limited by available space, and that’s where a low-level deck comes in. Any deck built less than 400m high is considered to be a low-level deck, and it’s the perfect style for transforming concrete slabs into entertaining zones but there are a few things to consider before tackling this project.

Covered outdoor patio with seating area, potted plants, and timber slat privacy screen

Low-level deck know how

Firstly, low-level decks need good ventilation to prevent moisture build-up underneath, which can potentially damage the timber. Drainage is another consideration – water that gets under the deck needs to be able to run off otherwise it can lead to mould growth, wood rot and structural damage.

And finally, because the deck sits so low, it’s almost impossible to get access to the underside once the boards are in place, so you need to give the decking extra protection against termites and rotting.

Now you know what to look out for, here’s a step-by-step plan to help you build your own low-level D.I.Y. deck project.

Steps

  1. 1

    Measure the space

    Begin by marking the deck’s perimeter. Start at either the edge of the house or the outer edge of the slab – this will be your primary line. Measure out from that edge the exact width the deck is going to be and mark those points. Snap a chalk line between the points, parallel to the house or edge of the slab. Repeat this process for the side edges, using the 3-4-5 method to ensure the corners are square. 

  2. 2

    Set out the deck supports

    Deck airflow solutions are vital for low-level structures – ample clearance means good ventilation – and the secret is adjustable feet. These are height adjustable so work in any space and allow for positive drainage. 

    Space these out equally along the chalk line, making sure you have a support about every 450mm. It’s not uncommon for concrete slabs to be uneven, so check each support with a spirit level and adjust as necessary. Screw them in place. Repeat the process for each position you plan to put a joist – you’ll need to set the joists about 450mm apart.

  3. 3

    Frame the deck

    Now you’re ready to add the frame. Some varieties of adjustable feet supports have a flange – or groove – that the joist slots into, which makes this step easy. Place the joist on the supports and screw through the flange directly into the joist to hold it in place. When all the joists are secure, go through and add noggins between the joists to hold everything steady and give the deck more structural support. Use a nail gun to secure these directly into the joists.

  4. 4

    Prep the timber

    Low-level decks need timber that’s going to stand the test of time because once the boards go down, you likely won’t be able to get to the underside to do any maintenance or pest treatments. Look for timber decking like merbau that’s sturdy and termite resistant. Even if it comes pre-oiled, it’s a good idea to give the undersides of the boards an extra coat of decking oil – to do this, set them out in a well-ventilated area and thoroughly coat with decking oil. Wait until they’re completely dry before moving on to the next step. 

  5. 5

    Position the boards

    To position your first board, measure parallel off the perimeter, drop a chalk line and place the timber board along it. Screw into each of the joists. Then, to ensure each board goes down straight, install every fifth plank parallel to the first board. These control boards create multiple reference points to help you stay aligned with your first board. When that’s done you can infill with the other boards.

    For good ventilation, it’s important to have a slightly larger gap between each board – use 6mm spacers to get a consistent gap between the boards.

  6. 6

    Box in the sides

    For a professional finish, install decking boards around the perimeter of the deck to close in the sides. Depending on the height of your deck, this will likely only be one or two boards high.

  7. 7

    Add a step

    If your deck is more than 190mm off the ground, you need to add a step. A treated pine stair kit is an easy option. Position the frame so it sits flush with the front edge of the deck. To secure it, attach the back of the ladder frame to the original slab. At the front, set H4 stumps into the ground with concrete and screw the ladder frame into these posts. Use more of the decking boards – and the same method described above – to infill the top of the step. 

    Timber deck with outdoor lounge chairs, hanging plants, and slatted privacy wall under a roof
  8. 8

    Finish your D.I.Y. deck project

    Now all that’s left to do is clean the deck thoroughly with decking cleaner and give the deck a final oil. Once the timber is dry, it’s over to you to set up your new outdoor entertaining area with garden furniture perfect for decks.

    If the space is big enough, consider creating zones with your furniture – such as a table area for eating and a lounging area for relaxing. Other features to consider are privacy screens and lighting. You could also soften the whole area with planters and climbing plants.

    Learn more about how you can plan and create the perfect decking area for entertaining.

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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.