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I'm wondering if this doesn't just mean broader planks of wood / spaced further apart — as might be typical of the sort of decorative 'screenng' sometimes found on the tops of buildings?
Note the term 'calepinage' (cf. KudoZ glossary), which refers to the layout / spacing of regularly-positioned things like tiles, bricks, etc.
WRT the balconies, a lot depends on what is meant by 'fond' — the underside, the 'floor', or the back wall? If it were the floor, one could certainly imagine thicker planks of wood, not too broad, and spaced pretty closely together (cf. decking) — you don't want people / things to fall through; whereas up on the roof (attique?), one can imagine the function of vertical (-ish) walls simply to be decorative and hide roof-installed plant, in which case, broader planks of wood would be appropriate, with much larger gaps between (to reduce windage!) — maybe even on an angle, like louvres — cf. the tops of some single-storey 'utilitarian' buildings, to evoke the notion of a 'pitched roof' — or as here, merely cladding:
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