This is generally how the
roof will look when a vent pipe is ready to be flashed. The underlayment
nails are shown to give an idea of how to
properly nail down the felt underlayment. The spacing between the
underlayment nails should be about 12 inches.
First, we'll check to see if we can install another
shingle. It looks like it will be close.
Since another course of shingles fit without
having to make any cuts, let's move on to the next step.
What we're doing now is
checking to see if the flange (flat part) of the jack will come down far
enough so that it extends down onto the
exposure (visible part) of the shingle. Take the lead jack and slip it
over the vent pipe (the dotted red lines indicate the vent pipe). See how
the flange doesn't come down far enough onto the exposure? We need to add
another shingle. Remove the pipe jack.
Take a full shingle and butt it up against
the downslope side of the vent pipe. Mark where the shingle needs to be cut.
We can mark it with a lumber crayon, scratch it with a blade, whatever is
Now butt the shingle up to
the side of the pipe. Make sure it lines up with the next course of
shingles. The blue circle indicates where we want it to line up. Make a mark
where the downslope side of the pipe lines up with the shingle. The mark is
indicated by the small red line.
The dotted red line in this
picture shows the approximate shape of the area we want to remove from the
shingle. Let's remove it now.
Here's the shingle with the
Now we'll set the shingle in
place and nail it down.
Now let's go ahead and put
another shingle in that same course. We're going to have to cut it, too.
Let's go ahead and make our
mark and cut it. It will look something like this.