Chapter 4: How to search for the source from the outside
You are most likely to find the source of your leak while working on the roof, but again, be safe while working at such heights. It is imperative now, on the roof, more than ever to be attentive to detail. You will be looking for any inconsistencies along the surface of the roof.
You want the roof to be dry, so make sure to wait as long as you need to after rainfall before you start work. As a starting point, use the length that you measured while inside the house to locate the general area of the leak.
Examine the area for any moisture, since the roof should be dry, this will help identify where there is water backing up and seeping through to the inside. If you run into any nails that have rusted, you have found your source. Rust is a tremendous identifier for roof leaks, so always keep an eye out for any sign of rust.
If you have still not found the source of your leak, chapter 5 is the chapter for you.