Arts Crafts Tile

HELP! with interior (doorless) threshold!?

I've chipped out an old concrete slab that had been poured into the threshold of an interior doorway (located between living room carpet and the tile of the adjacent now closed-in porch. After removing the concrete slab, I was left with the old framework of a pre-existing slider door (still nailed into place, under which I do not know....another concrete slab?). I would like to avoid removing the old framework....filling it with some decorative rocks for the threshold, but don't know what I should use to achieve this? What will hold the stones(rocks) in place? An arts'n crafts clear adhesive? Acrylic something? a product that can withstand foot traffic maybe. Or maybe I should stick with PLAN "F" and purchase the typical store-bought wood threshold and bag my creative idea! I'M GOING TO THE STORE TODAY! with or without you :LMAO!

I think I would stick to the wood threshold if I were you. People do not expect decorative stone and could trip and fall.

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