Homeowner in Long Island NY. trying to insulate and air seal my unfinished basement. Everyone mentions the sill plate and the rim joists as being the places that are most important to air seal. So I have done that. However, it seems that I’m getting a lot of air getting in the house under the metal termite barrier in the basement.  

The metal termite barrier in my basement  is put directly on top of the concrete foundation and the sill plate is placed on top of the termite barrier with a layer of fiberglass in between. House is built 1983

just wondering if anyone else has experience air sealing under the termite barrier. 

thanks!