I see this often while working as a Bellingham home inspector who serves all of Whatcom County and the outlying areas. Many builders, often dating back from eons ago, choose to leave old scrap lumber and debris in the crawl space. You know the story: It does not hurt anyone if they cannot see it.
That may not be true in the case of leaving cellulose scraps in the crawl space. Wood destroying organisms, often first rot and then wood destroying insects, tend to be attracted to such materials.
Below are examples of problems:


The bottom photo is an old cross-tie, used in pouring the footing and the foundation. This rots away and not only do you have decayed wood but also a water entry point into the crawl space where the open gap exists, after the wood is gone. Clean is better in the crawl space too.
Thanks for stopping by,
Steven L. Smith





Check out "This Day In History" -- music and vintage television from the 1950's through the 1980's. I enjoy writing these articles because they take me back to my days in radio broadcasting. Click on Elvis' gold record, below, to revisit those golden hits of yesteryear.

Good post, Steven. Checking the crawl space after contractors is a must.