Sometimes the water shows up at a ceiling spot distant from the leak.
Roof sheathing help leak tight.
If your ceiling has a plastic vapor barrier between the drywall and the attic insulation push the insulation aside and look for flow stains on the plastic often water runs to openings in the vapor barrier such as at ceiling light fixtures.
If you tuck window flashing under the foam sheathing you may create a leak.
Begin by removing the shingles down to the wood sheathing and slip a strip of adhesive ice and water barrier available where roofing repair products are sold under the soffit main roof joint.
Nail the drip edge to the roof sheathing at roughly 18 24 spacing intervals using roofing nails.
Some roof leaks are tough to locate.
Points to the installation of ice and water shield along the lower roof eaves protecting against ice dam leaks that are common on un vented roofs in cold weather or snow climates.
Run water over the low side of the penetration for several minutes while the helper watches for any water droplets.
Depending on how the roofs join you may have to cut a slot to work it in far enough.
The use of rigid plastic foam sheathing is also becoming more common in residential construction.
Flexible roof sealant apply flexible roof sealant black jack roof patch rubberized roof cement from a can or tube to fill holes gaps flashing and loose shingles around roof vent new vent shingles replace worn out roof vent with a new one and shingle around it to provide a better roof leak repair.