Structures Built over Crawl Spaces Develop Condensation Moisture and Mold Due to Improper Construction Techniques Not in Compliance with Building Code Requirements Necessary for Adequate Performance

Opportunities to investigate residential structures supported over raised crawl space construction, above natural soils, after having sustained functionality failures in south Florida indicate that there is a shortfall in, or lack of understanding associated with the knowledge required by professionals such as designers, contractors, building officials, and tradesmen in the construction industry. Numerous observed failure mechanisms and resulting damages indicate non-compliance with respect to requirements documented in the industry standards such as the Florida Building Code, the Florida Weatherization Handbook, and the Federal Regulation 10 CFR Part 440. Case studies with associated deteriorations to be discussed include various forms of damage and failure associated with inadequate or incomplete construction techniques and a lack of required details. Industry standards that should have been followed and complied with during the design phase and/or construction process, but that may have been ignored, misinterpreted, or simply unknown by the responsible parties confirm a level of neglect and incomplete construction techniques, as observed during forensic investigations that have exposed substantial damage and failure. Deteriorated conditions noted within the observed crawl spaces include sagging, deflecting, and/or failed structural components, deteriorated wood subflooring and floor joists, extensive fungal growth, elevated relative humidity and condensation moisture levels, reinforced concrete component spalling, reinforcing steel corrosion, efflorescence staining on exposed masonry stem wall foundation surfaces, excessive floor slab deflections, etc. The historical Southern Standard Building Code and the subsequent South Florida Building Code were precursor codes and the basis for the current Florida Building Code. Prescriptive recommendations and requirements exist in the Florida Weatherization Handbook and the Florida Building Code-Residential, Chapter 4—Foundations, Section R408—Under-Floor Space. The Florida Building Code Energy Conservation also contains crawl space insulation requirements. Foundation venting and installation details include minimum opening sizes, geometry requirements, vapor barrier requirements, and floor insulation installation techniques. Subjects of importance include appropriate ventilation of the crawl space, vent opening size and quantity requirements, location and geometry of the venting, the crawl space area, vapor retarder requirements placed over unfinished dirt floors, insulation placed over the subflooring and floor joist components, crawl space access, etc.