Spray foam insulation is wrong for a crawlspace

  Spraying the crawlspace with expanding foam seems to be the new fad. Does anyone really know what the stuff is, or how it works? The thing is, all products have a designed application. Sometimes we find a secondary use and it works great. Everyone knows duct tape has a ton of uses. But what about this spray foam stuff? It was designed for attics and the open cavities of above ground spaces (like when a wall in your living room is studded out, it gets sprayed in and drywall is built over it). Somewhere along the line somebody decided to start using it in crawlspaces. If you look at the installation videos for spray foam, it will show a technician spraying a nice even swipe, it expands, then they trim off the excess. Great…now try that same process laying on your stomach in a two foot high crawlspace. It just doesn’t happen.

  About a year ago, DryZone was contracted to repair over 100 crawlspaces in a condominium development in Lewes, DE. Several years prior they had the crawlspaces sprayed by another company that has since gone out of business. The tenants were complaining that the smells were getting worse and they had noticed some bounce in the floors. When we opened up the first door and saw all the spray foam, we were shocked. It was one of the worst spray foam jobs we had ever encountered. This company had sprayed from the dirt up to the floor boards. They even covered all the floor boards with foam. It looked just awful. Some areas were only an inch thick, other about 4 inches. There was no consistency at all. The real surprise came when we started to chip it off. The termite trails on the inside of the foam were like something out of a science project. When we talked to the property management company, they told us that the development did not have termites prior to the spray foam job.

  Termites need to cover themselves in “mud” when crawling through an open space. They need to protect themselves from drying out so they create a mixture of wood pulp, saliva, and dirt to makes these little trails. If there is a nice thick layer of foam covering the walls, they can move about much faster and easier. The wood in these homes was basically destroyed in some places. We are still working on this project, both because of the size and severity of the problem. When DryZone encapsulates a crawlspace, we always leave a small gap near the top of the wall. This is to allow a termite inspector to see if any termites have crawled up to the wood, and more importantly treat the problem before it gets worse. No one wants termites or ruined wood, so no one should have their crawlspace sealed by spraying foam all over the walls.