What are the minimum dimensions of a crawl space opening in millimeters?

What are the minimum dimensions of a crawl space opening in millimeters?

• A. 500 mm by 700 mm
• B. 400 mm by 600 mm
• C. 600 mm by 900 mm
• D. 450 mm by 650 mm

Answer: (A)

Access openings under a floor must be large enough for a person to enter and work comfortably, moving tools and equipment as needed. The minimum size of 500 mm by 700 mm provides sufficient width and height for practical entry and maneuvering, giving about 0.35 square meters of opening. Smaller dimensions would hinder movement and make inspections or repairs difficult, while this size is the smallest that still allows usable access. Larger openings would work, but they aren’t required to meet the minimum.

Access openings under a floor must be large enough for a person to enter and work comfortably, moving tools and equipment as needed. The minimum size of 500 mm by 700 mm provides sufficient width and height for practical entry and maneuvering, giving about 0.35 square meters of opening. Smaller dimensions would hinder movement and make inspections or repairs difficult, while this size is the smallest that still allows usable access. Larger openings would work, but they aren’t required to meet the minimum.