These are some examples of moisture problems and damage to exterior wood and hardboard siding applications I have seen recently in Aurora Colorado and Castle Rock Colorado. As the owner of Magpie Property Inspections, I see quite a bit or worn or damaged siding on homes. Often, it is due to deferred or neglected maintenance. In some cases, like the home pictured below, the improper installation of a window or opening allows water to run in behind the siding and trim, and the wood rots from underneath. This can occur unseen for a while, so it is important to check your home periodically for peeling paint, softness in materials, discoloration or looseness in the siding or trim.
Below is a photo of a cantilever under a kitchen wall. Moisture has seeped through openings in the siding and trim which were not kept caulked and sealed, and has now damaged the siding from the inside out. It will need to be removed and replaced properly. While there is no visible mold in this instance, mold can form in cavities behind these kind of materials. If found, it must be removed by a qualified contractor who is skilled in applying the appropriate remediation techniques for safe restoration.
In this case below, the siding and framing has actually rotted and come loose from neglect over time. Keeping the exterior of your home sealed, caulked, and painted is the best way to prevent problems like these. If your home begins to develop symptoms or wear and damage like these, have it addressed by a qualified contractor immediately.