A major use for asbestos over the years was for insulating. Walls were filled with asbestos insulation to block noise in multi-unit housing and apartments and to contain warmth in single-family dwellings. Attic insulation often used a product with vermiculite ore, which proved to have natural veins of asbestos running through it. And even water pipes were better insulated with concrete compounds strengthened by asbestos. Houses built between 1930 and 1950 are highly likely to have one or all of these forms of asbestos insulation, and even houses up through 1990 may have some vermiculite [source: EPA].
Asbestos-containing insulation can be coated, or encapsulated, or even wrapped in protective coverings to seal it from potential deterioration, or it can be removed, depending on the recommendations of asbestos experts [source: EPA]. Any cracked piping or crumbling spots of a wall or attic should be tested for asbestos, but as with other areas, it is best left alone altogether until assessed by professional.