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Hi All,
I am new to this forum. Having seen some impressive decking projects and amazing member support, I was hoping I could get some helpful feedback on my idea of building a low level deck in my backyard!
The deck I want to build will go over the existing lawn shown in the below photos. Decking surface will be a continuation of the existing patio tiled floor.
Hopefully the below images show the transformation I am expecting to achieve!
The ground height below the patio surface ranges between 140mm to 200mm. With the small depth available, I thought of building the deck with 19mm thick decking boards laid over a 90mm deep frame supported on steel stirrup posts.
90 x 45 MGP10 H3 treated pine is what I am thinking of for the construction of the frame.
I have two ideas for the frame as shown below. Whilst Frame 1 may be more economical I think Frame 2 would be easier to build with the lower number of stirrup holes that need to be dug in the small backyard.
Frame 1
Frame 2
I would much appreciate it if you could let me know your thoughts on which approach is more sensible and structurally sound 
Looking forward to hearing from you.
Many Thanks,
Janitha
Welcome to the Bunnings Workshop community @Janitha. It's a pleasure to have you join us, and many thanks for your questions about constructing a deck.
Both of your layouts look quite reasonable. I would presume the second will be more solid as you're using the double joists, but there are more solid lengths in the first. The first deck is going to be by far the easiest to construct with nowhere near as many connection points. The direction you want to run your decking will likely play the biggest part in choosing which of those designs you go for.
Have you considered using pedestal feet on pavers or DEKO 250 x 150 x 150mm Instant Concrete Foundation Block or TuffBlock 300 x 300 x 90mm Instant Foundation System Deck Supports?
I'm using the pedestal feet for a deck I'm building at the moment, and they are fantastic, as you don't need to level out your soil perfect. You just adjust their height to suit.
Your deck is exceptionally close to the soil, and adding adequate drainage is imperative to its longevity.
If you haven't already read through it, @Adam_W has a great guide on How to build a low-level deck.
I'll be keenly following along with your project. Please let me know if you have any questions.
Mitchell
Hi Mitchell, thank you so much for the prompt response and the ideas for foundations.
The pedestal feet on pavers idea might work for me. Did you have to compact the soil before you laid the pavers? I think the soil surface in our backyard is still soft, being an ex-golf course. I reckon over the last two years since we started living here, the areas with heavy traffic have some what become compressed. This observation led to the idea of using stirrups set on concrete.
As for the drainage, I guess the Frame 1 should be better as the members run along the direction of the slope. The slope in our yard is towards the house as I have shown below. When we first moved in, we had rain water collecting closer to the edge of the patio. Developer then installed some sort of a subsoil drainage line in the section shown in red. Although it works now I wonder whether I should install a proper drainage channel with grates at this location before I start working on the deck?
Hello @Janitha
Thank you so much for posting that update. I agree with your proposal of putting a proper drainage channel in the low area. If the rest of the soil in the area is the same, using a compacting machine will give you a stable base to lay your pedestal footing on. I recommend sorting out the drainage first before building the decking frame. I suggest using Pillar Products 1.8 x 25m Jumbo Weed Control Mat in conjunction with Ki-Carma 20kg 10-20mm Drainage Gravel.
Please keep us updated with your project. We look forward to seeing the start of your deck.
Eric
Hi @EricL thank you so much for reinforcing the need to get the drainage system sorted out first. The weed mat and gravel application ideas are really great also.
Are 19mm merbau decking boards suitable to be used as an alternative for joist to go over the tiled area of my patio (see image below)? After seeing some similar projects on this forum I am thinking of laying decking over the tiled area too. The maximum clearance available for the substrate is about 26mm.
Very excited to get on with the project
Hello @Janitha
Unfortunately using Merbau decking panels as a joist alternative is not going to work. The space of 26mm is not enough to build a deck. One option is to break up the cemented patio area to get the clearance that you need. However, if the cemented patio area has only been recently built, I suggest leaving it as is. Another way to blend it in with your deck is to re-tile the area in a tile with a timber profile on it.
If you need further assistance, please let us know.
Eric
Welcome to the Bunnings Workshop community @BriggsyNZ. It's sensational to have you join us and many thanks for your question about design software.
Let me mention @Janitha so they are alerted and hopefully can answer your question. The top couple of renderings appear to be made using SketchUp. They might have used it to create the deck plans as well.
Do you have your own decking project in the works? We'd be delighted to hear all about it and would encourage you to start your own discussion if you need any assistance or would like to share the details with us.
Mitchell
Hi @BriggsyNZ,
Let me also extend a very warm welcome to the community. We're looking forward to reading about your projects and plans.
Just to add to Mitch's reply, you might be interested in this Best Advice article - What software do you use for drawing plans?
Hope its helpful,
Jason
