Because the garage door is often feel, many builders prefer to upgrade
to an insulated door even where
energy efficiency isn’t an important
consideration.
Inexpensive insulated doors often
make use of the “laid in place” method,
in which sheets of polystyrene foam are
placed in the hollow steel pans and
backed with a vinyl liner. Better-quality
insulated steel doors use what’s sometimes
called “sandwich construction”:
Both the inner and outer faces of the
door are steel, and the EPS panels
between them — which are molded to
conform closely to the shape of the
steel skin — are bonded to the steel
with adhesive. In addition to providing
better thermal and sound insulation,
the bonded foam also dampens