First time poster and not a builder. Just wondering if the below is possible:

I want to deck over our front porch (~1m x 4m). The porch is currently tiled over a concrete slab. I was thinking of laying joists over the top and then decking on top of that; however, I was wondering if you can lay joists down so they arent as tall? I understand that this will make the deck less stable in a normal circumstance, but will this be the same as the concrete slab is already there? If I have the joists standing upright then it will be too tall for our entry way.

Thoughts?

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