Pentominostairway

Thanks to Nisrine El Ahmadi,(Belgium) for the idea of this challenge.

Make a stairway, with stairfoot and stairhead 1 and a landing, using a full set of pentominoes (see picture).

Make the stairway in such a way that the area is maximized.
The pentominoes have to be in one plane, and touch by a full sidelength of a unitsquare (point or corner connection isnít enough).
Look at the example below to have a better understanding of the challenge.

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