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Hello, new to the community here. I am looking to build a decking in my back yard and looking for some advice 
This is what I have planned so far, the size of the deck is 3m x 6m, the ground at the moment is sand, and it will be a relatively low decking and i have been thinking of 2 different options below:
1: Building with stirrup post and 90x90mm timber for stump, size for joists is 45mm x 140mm (picture below), wondering if this will be enough support for the deck?
2. Building the foundation with tuff blocks, my concerns is since the ground is sandy, will the tuff blocks sits well on the sand? or other wise if i get some concrete slab and use that as a footing for the tuff block, will the below be enough support or would i require more blocks?
Thank you
Hello @wenxin21
Welcome to the Bunnings Workshop community. it's sensational to have you join us, and thanks for sharing your question about your deck.
Can you please tell us a little bit more about your deck? Are you building a standard deck with bearers and joist on top or is it a single level frame? Using a 90x90 post for your deck is possible, especially if you'll be setting it in concrete. However, if you use TuffBlock, I suggest compacting the sand as much as possible with a compactor and using large pavers as a base for the TuffBlock. Please allow me to confer with my team-mate regarding the number of footings you've indicated in your plan.
If you have any other questions we can help with, please let us know.
Eric
Hi @wenxin21,
Although your lengths are within span tables, you have six joists connected to one "frame" piece, which is only supported at either end. I'd recommend you had additional support points as below.
Please let me know if you have any questions.
Mitchell
