Hi @lisamariedack,
A deck this low to the ground is possible, although the truth is, it will not last anywhere near as long as something with much more clearance. This is because there will be greatly reduced airflow around this deck, meaning moisture that finds its way beneath the deck will be unable to dry up. Over time, this inability for moisture to dry, will cause the timber of your deck to rot. You can still build a deck; I just think it is important to be aware of this.
With such limited space, the most important thing will be your selection of materials. As the timber appears to be in direct connection with the concrete slab and in very close proximity to the soil, using H4 Treated Outdoor Structural Pine would be my suggestion. With the use of this material, the timber can be directly supported by the concrete and attached to it using angle brackets and masonry anchors.
It is also worth noting that your decking materials will likely have a clearance requirement. For example, Ekodeck requires 40mm clearance from the ground beneath with adequate drainage and 90mm clearance without adequate drainage. With the low clearance, your decking boards are unlikely to be covered by the manufacturer's warranty. Again, you can still go ahead, I just think it is important to be aware of this.
Outside of these considerations, the principles are the same. Joists should be spaced 450mm and should be supported in line with the relevant span tables. On the dirt side of the deck, it would be much easier to excavate a bit to allow for support from a post or pedestal.
You might like to check out the following articles for some further guidance -
How to understand deck components
How to understand deck span tables
How to build a low-level deck
How to build a deck.
Let me know if you have any further, specific questions. I am more than happy to help.
Jacob
