Every building must be maintained in order to prevent outside weather from getting into the building. This is why roof maintenance is so important. If your roof is compromised, you have an increased chance of mold. This increased risk comes from compromised roofing material but also broken gutters, chimneys, or ineffective flashing. Roof maintenance is important to reduce water damage but also to prevent the health hazards of mold growth.
Whether your roof is tile, asphalt, tar, or metal, it can be compromised. Tar may need to be reapplied on seams or on an entire roof in order to maintain its waterproofing. Shingles need to be visually inspected at least annually with extra inspections following any major weather events. If the material on your roof is not watertight, moisture will soak through the sheeting, into the insulation, and it will sit waiting for mold to find it.
Broken gutters are common in areas that have harsh winters because water can freeze and expand between the gutter and roof or fascia. If you end up with icicles (which usually indicates insufficient insulation), these may tear down gutters. You may tear gutters down if you break off the icicles. Once gutters are torn away, they might expose areas where water can enter the roof. This is another situation where mold could grow.
Over time, the flashing around your chimney, vents, and skylights can warp and bend due to weather changes. Often, holes, bends, or tears in flashing can be easily repaired. If water gets into the roof, it must be cleared to avoid mold.
Mold does not grow inside of brick, but it can certainly grow on the outside of brick. This is especially true if that brick gets wet in a dark, stagnate place: thus, the mold risk of chimneys. Chimneys should have caps and flashing to prevent water from entering the home. If mold gets into the chimney, it can continue to spread inside the home.
Many people take roof maintenance for granted, but a roof leak can be disastrous to your ability to live in your home. It can also be a way to start a big mold infestation that may go unnoticed for months. If you get a large mold infestation, it may not be able to just be cleaned. You may have to remove structural components in your home in order to completely remove the mold. In the meantime, you run a great risk to your health if you have a compromised roof that increases mold risk.