Roof-Mystery Suspects
To the Editor
I'm writing in reference to your
May 1987 article "Mystery of the
Ghost Lines." From my roofing
experience, I have found that with
airtight roofs such as these, air
escapes from any point possible. The
new design that worked well for the
author of the article allowed the hot
air rising from within the house to
escape in a controlled way.
What I believe happened (in the
problem roof) is that heat escaped
between all vertical and horizontal
joints. But shingles will not move or
show as much movement vertically as
they will horizontally. Try putting
two nails six inches apart in a shingle,
move the shingle, then nail the last
two nails, The shingle