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A wooden subfloor for a house


If you're building a deck, you're going to need to support your decking boards. This is where joists come into play. Joists make up the deck frame, and they are also the key to the overall success of your D.I.Y. project.

Safety tip: Always wear the appropriate safety equipment (safety glassesear muffs and a mask, for example) and always follow the instructions for the product or equipment.


1Space your joists

To ensure your joists are spaced out correctly, divide the width of your deck into even sections.

Green Bunnings hammer
Pro tip: Joists should never be more than 450mm apart.
A Bunnings Team Member holding a measuring tape over a plank of wood

2Nail joists on bearers

Once your joists are marked out, fix them to the bearers using a nail gun or hammer. Remember to always use galvanised nails, which slow down rusting and corrosion.

A person using a nail gun to fix the joist into the bearer

3Secure noggins for further support

Noggins are struts that will give extra rigidty and strength to the framework. (Only add noggins in between every second joist.) For further support, it’s advisable to add brackets and screws to your joist where needed. It’s also a good idea to add adjustable feet to your joists in concreted areas. Add noggins to every second joist only.

A Bunnings Team Member adding a bracket to a subfloor using a nail gun

4Are you ready for the next step?

The fourth part in our seven-part series on How to build a deck is how to lay your deck.

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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.