How to build a low level deck?

[TheGrumpmeister]

Hi - and thanks in advance for any advice you can give.

Is this a satisfactory combination of materials and measurements for a build over a concrete slab? Refer attached. It's not exactly to scale.

Note - this would be free-standing and not connected to the house.

• Builders Edge 35-60mm Smallfoot Pedestals set at 50mm so the deck is 160mm to equal the entry brickwork height.
• 90 x 45 Joists
• 19mm decking boards

Do I need noggins? If yes - how far apart should they be?

[MitchellMc]

Welcome to the Bunnings Workshop community @TheGrumpmeister. It's brilliant to have you join us, and many thanks for your question about building a deck.

That 1500mm between feet is too far for my liking on 90 x 45mm. I wouldn't advise much over 1000mm as you'll end up with a spongey deck. I'd recommend five feet over that length.

Also, your outside joist is not supported over the 5000mm span, which will not work. If you want that counter-levered overhang on either side, you'd need to run your joists in the opposite direction and, therefore, decking boards. Are you running the joists in this direction as you want full-length decking boards, and if run in the 5000mm direction, they'd need to be staggered? 

Mitchell

[MitchellMc · Accepted solution]

I've just noticed that you want all sides counter-levered. Is this intentional, @TheGrumpmeister? An overhang on two opposite sides is quite easy to achieve, but it gets a bit complex on all four sides. I've added a rendering below of your joists in the opposite direction. However, given the four-sided overhang, you might as well keep the joist orientation. The rendering still illustrates how I believe you could support that overhang on the other sides. You need to stop your last joist short of the overhang, swap in some noggins that are fixed to the last joist, and then have a foot at least halfway along them. That should support the overhang and last joist/frame. Typically for a counter-levered section, you want a continuous joist running out to support the weight; you can't just have an unsupported nogging connect the section.

I hope that makes sense, but please ask any questions you might have.

Mitchell

[TheGrumpmeister]

Thanks very much. I've taken your advice and I'll place the joists using the principles in your rendering.

[MitchellMc]

Keep us updated @TheGrumpmeister, and please reach out if you need further assistance.

Mitchell