How to design and build low-level floating deck?

[coolnav]

Hi, 

I have done a lot of reading in this form on the Low Level floating decks, got inspired by some of the DIYers and decided to go ahead and make use of backyard by building a deck, I am planning to do a 6mx4m as shown below. Inspired by Good Times decking, will be using the adjustable support feet (deck height including bearers height + board height is around 30 cms).

I am planning to do this all by myself, to minimise the effort, I decided to lay the deck on the existing pavers using the support pedestals (i haven't decided which pedestals to go with like Tuffblock or the Good Times support pedestal), I also need the pedestal to be adjustable in some areas as the ground has some ups and downs. The pedestals will placed on top some concrete pavers to make it more stable.

For the decking I have decided to go with Merbau 90x19 boards. 

I would be starting the project soon and would like DIYers of this forum to go through the design and let me know if I have missed anything, need to fix the design or have any suggestions, really appreciate any help and guidance from this group.

Also I tried various online free planners but didn't get what I was looking for, like some online tool like https://www.blocklayer.com/ has good planning tool but doesn't allow break boards and thus was not very helpful.

If anyone in this forum can point me to a free online tool to help in designing the deck is really appreciated.

I am looking something very similir to the blocklayer online tool, that gives you the BOM, the exact layout of the boards with measurement etc.

Or anyone in this group can generate it for me , TIA

[JacobZ]

Hi @coolnav,

As you are using 90x45 as your bearers, following the Hyne Timber Bearer Span Tables, you will need a pedestal foot every 900mm.

You might like to check out How to understand deck span tables and How to understand deck components for some further guidance.

Let me know if you have any further questions.

Jacob

[coolnav]

Thanks @JacobZ  for getting back to me, All responses have been real helpful from the forum, got to learn a lot much appreciated.

@JacobZ / @EricL / @MitchellMc / @Dave-1 

I understand the span for distances for Joists and Bearers, but getting lost as soon as we come to building low level decks, as we are no longer placing the joists on top of the bearers, and using adjustable pedestals is making it more confusing :).

Please see below my current build so far, 2 frames (6000mm x ~1000mm each frame) attached together (still got another 2 frames to build, the pedestals on the on far right are currently there only to support the second frame, as soon as my third frame is attached to the second, i will fix them properly ). 

All my timber are 90x45 , as you can see the i have placed each pedestals at approximately 850mm (assuming bearer span allowed is 900mm and  joist span 1200mm), I am using 90x45 joist hangers for those that doesn't have pedestals.

Does this sound right?

2 Frames attached togetherJoist hanger for support

[JacobZ · Accepted solution]

Hi @coolnav,

Basically, a bearer is a bearer if it sits on a post or pedestal. 

Joists are attached to and supported by the bearers with no vertical support from posts or pedestals. The main characteristic that makes it a joist is being supported by a bearer. Whether it is sitting on top of the bearer or being attached to it with a joist hanger, it is still supported by the bearer.

Your bearers span 850mm between pedestals, which is inside the recommended 900mm span. Your joists span 1000mm between bearers, which is inside the recommended 1400mm span.

To put it simply, your deck frame is perfectly fine and will create a nice strong deck.

Let me know if you have any further questions.

Jacob

[coolnav]

Thanks, @JacobZ! You explained it so clearly that even a beginner like me could understand. This really boosts my confidence that I'm on the right track.

[coolnav]

@JacobZ ,

Another quick question, if you see my design with the frames where I join them together it literarily becomes a 90x90 (90x45 90x45 screwed together), does it mean that the span can be greater than 900mm or it doesn't matter and it remains at 900mm?

[Dave-1]

Evening @coolnav 

It kind of does but really I would stay the course you are on as it looks like a nice solid deck. I find changing things middle of the project always causes flow on effects. One way I tested out my deck as I built it was to lay some boards on top the stand (loosley) on it and see if it flexed yeah I looked like a kid doing a stress test but it put my mind to rest.

Dave

[EricL]

Hi @coolnav 

I second @Dave-1's recommendations and to stay with your current design. I don't recommend changing anything while in the middle of your build. As Dave-1 said unseen flow on effects will spread along your deck framing plan that could produce undesirable consequences. You are currently within the safe zone in regards to your footing, it would be best to stay within that zone so that you'll get a solid decking frame.

If you need further assistance, please let us know.

Eric