Allergy Alert for Champaign, Illinois

CASE HISTORY: Crawl space encapsulation

Introduction

Brian F. had had concerns about the crawl space below his 10-year-old condo and contacted us for a crawl space inspection. He was aware of moisture problems around the exterior of his home and wondered how, if at all, this might be impacting the crawl space below his home. He wanted to be proactive as he intended to move in the next 10 years and wanted to ensure that the value of the property was being maintained.

Initial Problem and Complaint  
  • Musty odor detected when the crawl space entry planks were removed
  • Water runoff problems around exterior of house in spring and summer
  • No odor detected in home
  

 

 

 

 

Inspection Results
  • Damp and humid crawl space
  • Distinct musty odor upon entering crawl space
  • Excessive relative humidity at 80% (should be <60%)
  • Wood moisture content excessive, ranging from 18% to 21% (should be <13%)
  • Plastic sheeting covering ~80% of crawl space floor
  • Early stages of mold growth on floor joists
  • Profuse condensation dripping from supply trunk and secondary vents
  • Water puddles on plastic sheeting from dripping condensation

      

     

      Standing water on crawl space floor. Condensation

                                                                                                      on trunk lines

 

Before crawl space encapsulation. Water on plastic sheeting, exposed cinder block.

 

Corrective Measures
  • Add 100 feet drainage tile to channel water to existing sump pump
  • Encapsulate crawl space with scrim-reinforced vapor barrier
  • Seal crawl space vents
  • Condition crawl space air with small portable dehumidifier

 

(Above) Before and after encapsulation in the crawl space. Exposed pea-gravel in "before" picture.

 

(Left; above left; above right) A clean environment after crawl space encapsulation.

 

 

 

 

 

 

 

Conclusions
  • Drainage tile effectively channeled incoming water to sump basin
  • Encapsulation and dehumidification stopped condensation from forming on supply trunk and secondary vents
  • Crawl space was dry and clean
  • RH maintained at 45%
  • Wood moisture content averaged 8%
  • Musty odor eliminated and crawl space smelled clean and fresh, precluding concerns about musty odor infiltrating into living area above
  • Indoor air quality improved and value of home preserved