Parallel chord floor trusses are
becoming more common in residential
construction (see "Framing
With Floor Trusses," 4/93). One reason
is that the open webs speed the
installation of plumbing, heating,
and wiring. Although building codes
don't require that pipes passing
through a truss space be
insulated, there are cases
where they probably
should be. Though desirable
from an energy conservation
standpoint,
pipe insulation may be
unnecessary when the
trusses are fully exposed,
such as over a basement
or a garage. But as this
case study shows, problems
can arise when
uninsulated cold water
supply and forced hot
water heating lines run
through a closed floor
truss space.
A Sagging First Floor
Eight years after its
construction in 1984,
the owners of the house
noticed that the first
floor was sagging in