There have been a number of blogs, among us home inspector types, discussing crawl space ventilation and lack of same. Some inspectors in other parts of the country are recommending that crawl space vents be closed. As I have pointed out, in this state the rules on this go beyond mere building codes. State law says an inspector who sees blocked vents must write them up as a problem in the report. Caveat: This does not include conditioned crawl spaces which, around here, have to meet rigorous standards to be approved at all.
Obviously if the home owner ignores the inspector's advice, there are no legal consequences. That does not mean no consequences will ever occur because, if the person lives long enough, he or she will see his or her wood frame house slowly eaten away by wood destroying organisms. That is what happens in the northwest at least.
I happen to have, as part of the curriculum at Bellingham Technical College, some of the model language from the Washington State Pest Control Association written in cooperation with WSDA. It consists of suggestions of language that an inspector should be familiar with when citing common concerns. The words do not have to be verbatim on a report, but they go along these lines.
Problem: Crawl space vents on home have been blocked.
Recommendation: Vents must be opened to maximize air circulation to the sub-area crawl space. The present conditions reduce or prevent airflow resulting in a lack of proper ventilation. Lack of proper ventilation is a conducive condition that can attract wood destroying organisms. Wood destroying organisms attracted to such conditions include carpenter ants, moisture ants, termites and wood decay fungi or rot.
These recommendations are from not only the WSDA PHD'd of entomology (bugs) but also members of the Washington State Pest Control Association -- if you were to see these guys some of them have probably been dealing with wood destroying organism problems for 50 years. Below are two photos from today taken in a home with crawl vents that have been closed for years. Otherwise it was an unremarkable home. The problem: Anobiid beetle. The casualty: About 25% of the beams, joists and posts.
Nice wiring too Typical anobiid damage, wood splits apart in strings
Thanks for crawling by.
Bellingham WA home inspections