21.   Finish the job by dabbing roofing cement under the new shingle.

22.   Finally, apply roofing cement to the underside of the shingles and press them down against the flashing to form a seal.

23.   I suggest you caulk that space, immediately under the threshold, with an asphalt roofing caulk or roofing cement.

24.   If you glue it, slather roofing cement in the space, and slide the new shingle into place.

25.   If you nail it, nail right at the top of each slot in the new shingle, then slather roofing cement on each nail head.

26.   If the flashing or the roofing cement deteriorates, gaps open up that allow water to leak into the attic.

27.   If the shingle does not stay put, slather on a little roofing cement between shingle and drip edge as you press it back into place.

28.   Instead, raise the shingle and cover the exposed area with roofing cement.

29.   Lift the overlapping shingles around the cap, apply a generous bead of roofing cement beneath them and press in place.

30.   Naturally, it is better if the flashing were touching the shingles, glued with roofing cement.