Roof leaks usually appear during storms, when you can't make permanent repairs. But you can take some steps to temporarily divert or halt the flow of water, as shown below.

Generally leaks begin at a roof's most vulnerable spots—at flashings, where shingles are damaged or missing, in valleys, or at eaves. Often, the water shows up far from its point of origin after working its way through layers of roofing materials and down rafters to collect in a puddle on the attic or bedroom floor.

During a storm, trace the course of water from where it's dripping through the ceiling to where it's coming through the roof. Drive a nail or poke wire through the hole so you can find the hole later when you get up on the roof.

Once the roof is dry enough, check it thoroughly looking for weak spots that indicate a source for the leak. Keep in mind that the point where a nail or wire is poking through may be below the actual source. Make permanent repairs as described on pages 31-33.