The first question is which floor, and the second is whether it rained
Two questions asked in the first thirty seconds sort a roofing inquiry more accurately than five minutes of general conversation.
Water on the top floor after rain is usually a roof call. Water on the third floor of a six story building, in dry weather, frequently is not, and finding that out on the phone saves an estimator half a day.
Then get the building: type, number of floors, whether it is attached on both sides, and who owns it. A caller who turns out to be a shareholder rather than the owner changes the whole path, because the decision belongs to the board and the managing agent.
Write the script and hold to it. Everyone answering the phone should ask the same things in the same order, so the notes are comparable and nothing depends on who happened to pick up.
Recording calls will show you where the conversation falls apart, usually in the same place every time. Recording laws vary and change, so confirm the current rules with your own counsel before you turn anything on.