Low-level composite deck over concrete

[diy_hausdesigns]

Ekodeck boards assembled over old concrete to create a new outdoor entertaining area.

• The project
• Steps
• Tools and materials
• Before and after
• How to build a low-level deck
• More inspiration for your decking project

The project

As part of the backyard renovation, we decided to build a deck as an entertaining area. We decided to use the existing concrete section and extend over part of the lawn area.

Steps

Step 1

We built the frame using H3 timber at 450mm centres, propping it up with some bricks.

Step 2 

We then added some joist tape to protect all the the timber. 

Step 3 

We levelled the deck using plastic pedestals and ensured it was flat.

We also applied more weed mat over the non-concrete area to avoid any potential weed growth.

Step 4

We then started installing the decking boards starting with the edges and then laying the boards using the Ekodeck quick fix system.

Tools and materials

• Ekodeck boards
   

• Ekodeck quick fix
  
  

• Plastic pedestals
  
  
• 70 x 45mm H3 timber
  
  
• Joist tape
  
  
• Bugle screws
  
  

• Weed mat.
  
  

Tools used in the project:

• Mitre saw
  
  
• Clamps 
  
  
• Drill
   
• Decking screws.

Before and after

How to build a low-level deck

Experienced Workshop community member Adam covers everything you need to consider in How to build a low-level deck.

More inspiration for your decking project

A low-level composite deck over concrete and soil by community member oninpena was completed after getting advice from resident Bunnings Workshop D.I.Y. experts Mitchell and Eric.

Workshop member ProjectPete was pleased with the results of his poolside composite decking project.

Check out our Top 10 most popular deck projects and the Top 10 most popular low-level deck projects to get inspiration from other Workshop community member projects. 

[BAditya]

Hi @diy_hausdesigns,

I am Adi and i am planning to build a deck, just wanted ask do we need to anchor these plastic pedestals to ground?  if not then are they unstable? 

[MitchellMc]

Hi @BAditya,

Hopefully @diy_hausdesigns can let you know of their experience with the pedestal feet.

I've built a deck with them, and fixing them is unnecessary. The weight of the deck holds them down. I created a relatively small 3000 x 3000mm deck, and it's rock solid.

Mitchell

[diy_hausdesigns]

Hi @BAditya I did not anchor them in my build. The weight of the whole deck is more than enough to hold it down as @MitchellMc mentioned. 

I'd recommend taking the time adjusting the pedestals to be completely flat on the surface. I Had to do a few re-adjustments with the frame on to ensure everything was flat and it worked out well.

All the best 

[marshallman]

I have a low level footpath that I am decking, approx 10m x 1m. Boards will run along the length of the footpath and joists will run the width (1m). I will have each joist supported 150mm in from each end with a pedestal, therefore span will be around 700mm (<1000mm recommended for 90X45).

With 450mm spacing, I will have 23 joists, 46 pedestals. It seems like an overkill for 10m2 of decking. My question is do I need every joist to be supported with 2 pedestals?
Could I support every second joist with a 1 support at the centre?

[MitchellMc]

Hi @marshallman,

The first thing to point out is that you might find it difficult to procure 10-metre lengths of decking. That's exceptionally long, and the longest we have is 5.7m. So, you might need to consider having a join in the middle. A single board that separates the two lengths perpendicular to them is a good way to deal with that and to create some interest.

AS you've mention 1000mm is within the span capabilities of 90 x 45mm. So, as long as the rim joists (side frame) are supported adequately every 1000mm, that should be fine. I've created some renderings to illustrate below. Regarding decking, 90mm boards in the middle, framed by 140mm on the outside, work well with your 1000mm width.

Please let me know if you have any questions.

Mitchell
 

[marshallman]

Thanks Mitchell 

Yes, will be using 5.4m boards. So will have a single board breaking up the 10m.

Awesome, thanks a lot for that.

Due to height restriction I can't fit a 140mm rim joist. Would a 90x45 be okay?

[EricL]

Hello @marshallman 

The 90x45 framing timber should work just fine, but I would suggest bringing the footing closer together to about 800mm just to be safe. 

If you need further assistance, please let us know.

Eric