Crawl Space Insulation – Building Science 101

As the cold winter months approach, crawl space encapsulation contractors can play an important role in protecting the environment and saving customers money on their heating costs. Most people don’t give their crawl space a second thought until there is an issue.

The Wrong Way To Insulate a Crawl Space

Old school methods told us to insulate the sub-floor (crawl space ceiling). It seemed perfectly logical: cold floors above, insulate beneath. However, today’s building science has proved otherwise.

The Right Way To Insulate a Crawl Space

To get the most “bang for the buck” for your clients, Contractors should insulate the walls and seal any air leaks. In other words, treat a finished crawl space just like a finished basement.

Why Concrete is Not a Good INsulating Option

Concrete possesses almost no insulating value (i.e. an 8in thick concrete foundation wall has less than 1 R-value; R=resistance to heat flow). If left uninsulated, the heat in the crawl space will move right into the cold concrete, in effect, cooling the crawl space air. As this cooled air moves upward (known as “The Stack Effect”) into the living areas of the home, heating bills are increased and energy is wasted. “The Stack Effect” (as hot air rises in heated buildings, cold air is sucked in to replace it) answers the age old question, “If I do not heat my crawl space, why should I insulate it?” It also reveals the problem with insulating the crawl space ceiling; it is all but impossible to make this insulated area “air tight”, allowing the cold crawl space air to be sucked up through it and into the home.