Originally Posted by dbogey
I have a cape cod style home with two dormers in the front and a rear dormer. Should flashing go on two sides and the bottom of the dormers. Also the roof is not finished and I've noticed some tears in the underlaminent (about 2 inches) the shingles have not been applied yet.
The typical flashing that are required along the side walls of the dormers are sometimes referred to as baby tins or as step flashings. They are about 3" x 3" by 7" in length. Their placement is mostly unnoticeable, since the bottom portion goes under the shingles and the there is a 90* bend and that vertical portion runs up the side walls of the dormers. It is then covered either by the siding product alone, or with a tyvek type wall wrap or even better, with a strip of Grace Ice and Water Shield to prevent downward migration of behind siding condensation or rain water.
Vinyl siding is not a water-proof product, if that is what you have and all flashings must be finalized with that in mind.
Along the front base of the dormers, there should be a roof-to-wall apron flashing installed, where the vertical segment is run behind the siding and the remainder should be bent at the same angle as the pitch of the roof, which, if a cape cod usually range from an 8/12 to a 12/12 pitch bend.
Sometimes the portion of this flashing which extends down onto and counter-flashes the top course of shingles which abutt the base wall of the dormer may be covered with shingles for a supposed cosmetic appeal. Although well intentioned, this is not the correct application method. The metal should more properly be lying over the top of the shingles.
As far as the tears in the felt paper underlayment go, they should be sliced to lay down flat and then if deemed necessary, hace a small section of felt installed over it. It will not majorly hurt anything too much if this action is not taken, as long as it does not rain.