Your roof may be telling you something. There are various reasons why roofs leak. Here are 9 warning signs that present reasons for concern during the life of a roof. There are also many less obvious items which allow water intrusion which are frequently missed. Small roof leaks cause rotten wood and even mold and mildew just like large leaks do. However, small roof leaks are frequently not discovered, by the untrained eye, until they are large enough to become obvious. By then complete roof replacement is frequently necessary. The best way to be certain your roof is in tip-top shape is to have it regularly inspected by an experienced roofing professional.