When it comes to roof damage, most homeowners are more concerned with inspecting the exterior of the roof for problems. Not all roof problems originate from the outside, though. In some cases, roofs first begin to fail internally due to damage that is suffered on the underside of the roof decking.
1. Attic Condensation
Moisture can condensate in the attic for a myriad of reasons, but a combination of poor insulation and insufficient attic ventilation is the usual culprit. Condensation and moisture from inside your home can collect in the attic, where it will attach to the underside of the roof decking if there isn't enough ventilation. The decking will then suffer moisture damage and begin to rot from the inside. Your roof should have vents along the underside of the eaves and along the top ridge of the roof, at a minimum. Depending on the shape and size of the roof, you may also need vents between the eaves and roof vent.
2. Improper Venting
Poor ventilation in other parts of the home can also impact the health of your roof. Certain rooms, like the bathroom and kitchen, are typically equipped with moisture vents. Ideally, these powered ventilation systems should route to the outside of the house so moisture doesn't become trapped inside. Unfortunately, sometimes a ceiling vent or even a dryer vent may be routed into the attic, where condensation will collect and cause rot damage to develop on the underside of the decking, on rafters, and even on the wooden trusses that support your roof. These vents need to be routed properly to the outdoors to prevent any damages.
3. Support Removal
Damage can sometimes occur when a DIY improvement in the home isn't properly researched. If you are thinking of moving or taking down a wall in your home, don't start the job until you have your plan vetted by a structural engineer. For example, it may be tempting to remove a partial wall in order to open up a room, but that wall may have been incorporated in the design because the frame is part of the support structure of the home. If you remove it, the roof may begin to sag or it could even collapse. Don't try to circumvent permit processes for a DIY project, since these are often designed to catch errors like removing necessary roof support.
Contact a roof replacement service in your area if you suspect issues with the underside of your roof, or for more information about roof replacement.