Preheat oven to 450 degrees. Line a baking sheet with parchment paper.
To make the chips, peel the plantain by slicing off the ends, then cut in half lengthwise and then using a paring knife, peel the skin off in strips. Peal the turnip, parsnip and sweet potato with a potato peeler.
Using a sharp knife, slice each root vegetable into even thin slices. If you have a mandolin slicer, this would work even better.
In a small glass bowl, melt the coconut oil in the microwave briefly, about 10-15 seconds.
Place the root vegetables in a large mixing bowl, toss with the coconut oil and salt and turn out in a single layer, onto the baking sheet. You may need to roast these in two batches.
Roast for approximately 20-25 minutes, turning once and rotating the pan (if needed) until you have crispy golden brown chips. Remove from the heat and turn out onto a paper towel to soak up any excess oil.