How to build a small deck using modular decking kit and adjustable supports?

martyjames

After further research and helpful input from you guys i am now planning to build an approximately 3m x 3m deck (no pergola) over a slightly sloping concrete slab in my backyard (pic attached).

I am a very basic diyer so want simple and easy to understand but want the deck structurally sound and long lasting.

I found Bunnings sell Modular Decking Base Frame kits like https://www.bunnings.com.au/1144-x-1144mm-modular-decking-70-x-45mm-ekodeck-base-frame-flat-packed_p0273355 etc

I am thinking to use 9 of these kits 1144mm x 1144mm to get a base roughly 3.5m square.

I will use the Modular decking support feet to level the frame : https://www.bunnings.com.au/50mm-modular-decking-adjustable-support-foot_p8451224

I watcheds this video from Bunnings on how to put it all together: https://www.youtube.com/watch?v=1tjQdmsmkP8

Over the to of the frame i will install composite decking

Quesions

1.The video does NOT show the frame being attached to the ground at all - does it need to be? If so how would i attached it to the concrete slab? ( i can easly attach to the low wall at back of yard - is that ok?)

2.Can you send me a link to the correct "battern" screws refered to in video

3. How would i work out which length of Modular decking support feet to buy? They come in 50/100/150mm lengths from your website

4. Is the Modular Decking Base Frame kit timber 100 percent weather proof and does not require any finish?

5. I am thinking i need a very long spirit level to ensure frame is level - can you please provide a link to suitable level

6. Can you send me a link for suitabe screws to screw the frames together if different from "battern" screws in no.2 above

Is there anything else i need to take into account or buy?

Thanks in advance

Martin

JacobZ

Hi @martyjames,

I'll try to answer your questions in an order that will make sense during installation.

Working out which length support feet to buy would require a level. Over the distance you are proposing, a laser level would be the best option, but may be cost prohibitive. A set including a long level and a shorter level such as Stanley FatMax 2m And 600mm Spirit Level Combo should be adequate for your project.

Start by putting a mark (datum point) at the desired finish height on the high side, taking into account the pedestal foot, thickness of the deck frame and the thickness of your decking boards. Using 70mm thickness of frame and 23mm for the thickness of the composite decking board as an example, then adding room for the pedestal foot, I would suggest this mark should be no lower than 130mm above the slab. Once this datum point is set, you can use the laser level, or long level to mark a line at this height across the roughly 3.5m to the other side of the deck. This will allow you to once again measure down from your line and calculate which pedestal feet you will require. Please note that at higher heights, Good Times Co. require steel supports such as 140mm Modular Decking Support Steel for added strength and stability.

You might want to have a look at Good Times Co. - Decking Planner as well as the assembly instructions during the planning stage.

All of the modular decking kits from Good Times Co. are made from H3 treated pine, which is suitable for use outdoors but not in direct contact with the ground or fresh water. This level of treatment provides protection against decay and insect attack, making it suitable for applications such as outdoor decking, fencing, pergolas, and other outdoor structures where the wood may be exposed to weather.

While not specifically advised in their installation instructions, I would suggest attaching the frame to the ground is certainly worthwhile. The weight of the structure should do a lot to keep it in place, but I would be far more comfortable knowing that it is mechanically secured. This could be achieved on the concrete slab using something like Pryda Post Anchor Bolt Down Heavy Duty 90mm M12 suitably attached with masonry anchors to the concrete and batten screws to the frame. It would also help to fix it into the low wall as you've described.

The advised batten screws are ZENITH 14G - 8 x 75mm Class 3 Galvanised Bugle Batten Screws or a suitably galvanised screw of the same size.

I hope this helps to clear things up a bit. If you need more advice or any clarification, please don't hesitate to ask as I'm excited to see your project progress.

Jacob