Building paper refers to a thick paper that is water-resistant and useful as an insulation material. Another name for building paper is tar paper. Many manufacturers use bitumen, a derivative of natural asphalt, as the filler between pieces of kraft paper. This substance acts as the water barrier for this paper. This type of paper has been in use in the construction industry for almost a century. In past years, some builders have started using housewrap for some applications where tar paper was popular for many years. However, building paper has some advantages over building wrap such as not breaking down in sunlight and being a good water barrier. Builders use this paper in many applications. It can go behind roofing and siding to provide a moisture and air barrier. It can go down in wet areas of the house to prevent water from getting to the underlayment.