Dave writes from Summit, New Jersey: "I've got a partially floored attic that vents to the outside. I've put additional batts down over the un-floored bits. Can I put fanfold over top of the flooring for additional insulation? Even If I pulled up the floor, there isn't more than 1-2" of room. The attic gets very little foot traffic."

Answer: Fanfold is a re-siding board used over existing vinyl siding before re-siding a home. We have no recommendation for using it in an attic. If any type of foam insulation is used it will need to be covered with a 15-minute thermal barrier for fire safety.