Wind pressure is positioned along the “windward” and “leeward” sides of a structure or building.
Understand that the windward pressure depends on the wind force that is alongside the height of a structure or building, and the leeward pressure is presumed to be constant.
The leeward pressure is negative wind pressure that is in essence pulling (not pushing) on the structure or building.
When both the windward and leeward pressures are in the same direction, then the
combined wind load pressure is determined by subtracting the negative leeward wind pressure from the positive windward wind pressures.