How to build low-lying deck over concrete and lawn?

[SMUCKY]

Hi all - new here & hoping to maybe have some questions answered regarding some upcoming work im planning at my place!

We have a small backyard that is half concrete/half grass, we are wanting to make the 47m2 space more useable so am planning on decking over the whole thing essentially with a roof covering over the top one day too. Due to poor drainage in the existing grass area I will be starting off by making the drainage sufficient, concreting in the posts, & then covering essentially the whole backyard in blue metal then build the deck over the top. Due to the small height I have (70mm) ontop of the slab I will be using ClickDeck's extra low profile system to make the job possible. Then due to the small clearance in the grass area I have, the deck will be a single-level deck design & I will be leaving the finished height of the ground below much lower than it is currently as to avoid moisture issues under the deck.

My question is, judging by my rough plans I drew up. Am I in the right direction? Do I have too much framing as it does seems like a lot. Although I have based most of my measurements off of others advice but wondering if its overkill.

Essentially plan on concreting in posts, notching out posts to sit joists on & running a joist only system with hangers in place due to my overall clearance.

I'm aware of council requirements on decks & will have to alter the design to suit.

I'll include photo of what the backyard looks like now as well as my plans.

Thanks in advance!

Blake

[EricL]

Hi @SMUCKY 

Your decking frame design looks great. I'm putting my vote with design number one as it spreads out the support in a larger pattern despite using 90x45. The increased number of Tuff blocks will prevent your deck from having a springy surface. The more support your decking frame has the more stable it will be. 

My best advice is to make sure to paint the bottom of your frame with Gripset Betta 1L Waterproofing Membrane Bitumen Rubber and apply CAgroup 50mm x 20m Bearer Protector G-Tape to the top surface to extend the service life of the frame.

Let me call on our experienced members @Dave-1, @Nailbag, @TedBear, @Jewelleryrescue and @JoeAzza to see which design they'll vote for.    

If you need further assistance, please let us know.

Eric

[Dave-1]

Good Evening @SMUCKY 

Now thats a lot of effort in planning. Nice to see.

My Vote is drawing 1.

I havnt used tuff blocks so not speaking from experience for that. I do like the spans and the costings of both tho.

I do have concerns about council allowing that much of the yard to be decked. Id check sooner then later to verify.

The drainage for the area, I am not keen on French drains per say. I prefer dish drains as you can see what they are doing and dont clag up. WIth your suggestion of blue metal across the area I am not sure why? You will be removing soil in the first place I think? Id factor in some dish drains instead to a drainage pit conected to the stormwater system. 

Id love to see your project unfold As in post the finished steps throughout for a project. Please take a bunch of photos.

Dave

[Nailbag]

Hi @SMUCKY I would also go with option 1 with @EricL 

There are loads of similar projects on the workshop site to refer to, most with additional information from those who have installed them, issued and work arounds they have faced. It's worth surfing about to gather as much information as possible and learn by what others have done both well and haver not.

Nailbag