Ventilation worksheet — use only after confirming the governing rule
Marion County's reviewed new-mobile-home checklist gives ratios for that inspection path; it is not proof that the same formula governs every existing-home skirting replacement.
Scope noteFor a new installation under the cited County checklist, the published ventilation reference changes with vapor-barrier status; confirm whether and how it applies to this replacement.
- Enclosed crawlspace square footage
- Vapor barrier present/absent/unknown
- Net free vent area per selected vent
- Confirmed authority and rule
- Condition
New installation under the cited checklist without vapor barrier
- Ratio
1 square foot of ventilation per 150 square feet of enclosed area
- Condition
New installation under the cited checklist with vapor barrier
- Ratio
1 square foot per 300 square feet of enclosed area
Planning estimate clearly labeled 'not approved until the authority/park confirms the applicable ratio, distribution and access.'
Mark at least one planned service access location and confirm its required size under the applicable rule.
Never publish the calculator result as a permit, code approval or universal replacement requirement.
Official sources and scope notes
- New Mobile Home Permit and Inspection Checklist — Marion County Building Safety