There are two sides to the Thermafleece Breather Membrane, a gey side with overlapping markings (dashed line) and a white side. The grey side should face outward and the white side should face inward toward the inside of the building so in a floor, the grey side faces the ground and in a roof, the grey side faces the sky.
The membrane is vapour open in both directions so if the membrane is inadvertently installed the wrong side out on a floor it doesn’t impact on the performance. The grey side has a higher UV stability which is important for roofs and walls when the membrane is exposed to light during installation but not relevant for floors.