Hi Jay,

I'm being told by a roofer that he has the ability to install 6 inches
of ice and water shield up a wall, behind the siding, without removing
any siding. He says he uses GAF ice and water shield. The plan is
to put ice and water shield on the deck of the roof and also install
it 6 inches up the wall and then install the step flashing along that
roof/wall.
Again, he claims he can install the ice and water shield 6 inches up
the wall, and underneath both the siding and tar paper, without
removing any siding. Is it REALLY possible to do this without
removing any siding, and is this the correct way of doing things?

It might be possible:

1. IF there are no nails in the lower 6", or they can be removed without
seriously damaging the siding.

2. IF the siding can be pulled away from the wall enough to slip the
membrane behind the siding.

3. IF there is a gap between the siding and the roof deck (there should
be at least an inch or two) to allow the membrane to be slipped up under
the siding.

The protective plastic covering the adhesive backing would need to be
left in place behind the siding, or pulled out once the membrane is in
place. Difficult, but doable.

Assuming these conditions can all be met in your situation, it would
probably be possible to slip the membrane under the siding. Especially if
they work with smaller pieces near the wall. You may not get adhesion to
the wall behind the siding, but that shouldn't be a big issue on a
vertical wall.

Slipping rigid step flashing behind the siding will probably be more
difficult than slipping in the flexible membrane. That kind of depends on
how much gap you have between the roof and siding, or if the bottom of
the wall is exposed so the flashing can be slid up along the wall from
the bottom.

In an ideal world it would be best to remove siding above the roof. But
there's probably a way to work within the existing structure if you have
to.

Good luck,

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com