Metal Sales Snap-Loc 24 Installation - Manual (Page 17)

© Metal Sales Manufacturing Corporation / Subject to change without notice. 10/99
SNAP-LOC 24
16
SYSTEM EXPANSION / CONTRACTION
CAUTION
Use extreme care when working next to insulation. The insulation will provide a
false sense of security by hiding the view of the ground below the insulation.
SNAP-LOC 24 PANEL
Steel roofing panels are subject to dimensional changes after installation due to exposure to varying
temperatures. The greatest influence is solar energy. Steel roofing absorbs various amounts of heat
depending upon color, finish, angle of exposure, and time of exposure.
The relationship of ambient temperature to building structural temperature must be considered when
designing a Snap-Loc 24 roof system. The floating clips for the Snap-Loc 24 panels are designed for
expansion and contraction of the panels in the longitudinal direction. Lateral expansion and contrac-
tion is accomodated by the configuration of the panel cross section and causes negligible panel
movement.
When the total length of panel run exceeds the capability of the floating clips to accomodate the
thermal movement, expansion joints must be designed into the structure.
INSULATION
In most cases insulation is installed directly under the roof panels. Insulation is recommended on all
applications to act as a sound barrier, prevent condensation, and increase insulating value of a roof
system. Roof panels installed over open framing without insulation will cause excessive roof noise.
It is recommended that either urethane thermal blocks or 1
1 /
2
" blanket insulation be used as illustrated
to minimize noise potential.
Many different types of insulation can be used with the metal roof panels. Blanket, batt, rigid, and
reflective insulation are just a few. Please contact your insulation supplier for specific recommenda-
tions on type of insulation, vapor barriers, and installation procedures.
When applying a compressable type of insulation over open framing members, rigid thermal blocks
can be used to help eliminate heat lost at purlin locations. See chart on page 17 for available Thermal
Block systems.
DESIGN / INSTALLATION CONSIDERATIONS
(CONT.)
AREA OF LEAST RESISTANCE
TO HEAT LOSS
PURLIN
COMPRESSIBLE
INSULATION
RESISTANCE TO HEAT
LOSS IS INCREASED
THERMAL BLOCK