Final answer:
One ventilation opening shall be within 6 feet of each corner of the building.
Step-by-step explanation:
In regards to under-floor ventilation, one ventilation opening shall be within 6 feet of each corner of the building.
Simple air vents (commonly brick type vents with small holes in them) strategically positioned around the sub floor perimeter is the most common measure to ensure sub floor ventilation.
Subfloor ventilation is a system that helps to extract the damp air from your home and allows fresh air to enter places under the floor. It's installed within your subfloor space preventing excessive moisture from seeping into your home.
Ventilation openings in external walls for underfloor void must be provided so that there is a free path between opposite sides and to all parts of the void. The minimum requirement for openings is that they equate to 1500mm^2 for each metre run of wall.