The home inspection service observed a black substance covering a partial area of the roof sheathing. The Hamilton home inspector noted that the area in question was close to the main floor bathroom. The area close to the attic hatch did not have the black substance on the roof sheathing. It was suspected that the substance was a fungi growth possibly mold. The bathroom was not exhausting to the exterior but was suspected to be exhausting into the attic space. The Hamilton home inspector alerted his client and advised her that the bathroom should be exhausted to the exterior and that prolonged moisture in the attic can cause structural damage to the roof sheathing and framing.