Your visual inspection provides you with specific issues as indicators of a mold infestation, such as musty odors, water damage stains, and suspect mold growth. If you suspect mold in your home or office building, start with an exterior inspection because the outside can give you a good idea of what you may find inside. The exterior surfaces of a building, from foundation to roof, make up its envelope which is designed to repel excess water. Look for situations and places where moisture can enter the structure. Your exterior inspection should encompass the chimneys, decks and porches, garages, gutters and downspouts, foundations, slabs, and crawl spaces, landscape and drainage, siding, roofs and eaves. Your room by room interior inspection should include the HVAC filters, mini-split system, framework, wall cavities, wall coverings, decorative wallpaper, plaster, masonry, paneling, ceilings, skylights, windows, doors, and flooring. In the attic, check each rooms ventilation to make sure it is piped out the roof, not exhausting into the attic.