I’ve heard about crawl space encapsulation. Am I better off sealing the vents to my crawl with a rigid foam board or insulating between my floor joists and keeping the space ventilated?
If you have or want a non ventilated sealed crawl space, full encapsulation, then you probably don’t need to add floor insulation. Traditionally, crawl spaces have been vented to prevent problems with moisture. However there are a growing number of building professionals that recognize the benefits of a moisture controlled unventilated crawl space.
There are two main reasons for this line of thinking: