I'm slowly reflooring my house with hardwood, and ripped up one room's carpet last night. Much to my surprise, I found a rather sizable hole underneath the carpet that they just carpeted right over. I have a pretty cool, moist crawl space, so I'd rather not just lay down the builder's felt and floor over the hole; I don't think it would be a good idea to expose the hardwood directly to the crawl space.
I need some ideas on how to fill this hole well. Is there some kind of insulation foam I can just spray in, for example?
Apparently I can't post links or images (and the attachment upload thing breaks on every image file I try to upload), so you'll have to piece this URL back together. Copy and paste this into a new browser window: cl.ly/5QQD