Moisture marks, brown, yellow, or grey stains, and peeling paint on walls and/or ceilings could all indicate a damaged, leaking roof.
Also take a peek in your attic, where damp rafters or leaks could additionally point to roof damage.
Energy Costs
If you experience a sudden surge in energy costs, it could be a sign that your roof ventilation has been compromised.
Call in a Professional
Although you are the first line of defense when it comes to spotting roof damage, be aware of your limitations and do not hesitate to call in a roofer for a professional inspection.
Other things to look out for are Missing shingles, cracked or damaged shingles or tiles, missing or damaged flashings and water coming into your home from the chimney.