Symmetry-fence

Thanks to Livio Zucca (Italy) for the idea of this challenge.

Use a full set of pentominoes (see picture)

to make a fence, 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 isn’t enough).
Look at the example below to have a better understanding of the challenge.