Insulating Concrete with Galvanized Steel Centering
Vermiculite Lightweight Concrete: Insulating Concrete with Galvanized Steel Centering
This system provides a maintenance free, economical roof system. It consists of high tensile galvanized steel centering, welded to attached with self tapping screws to the supporting steel framing together with either a 1-6 or 1-8 mix of vermiculite concrete. The thickness of the concrete may be varied to provide necessary drainage slope. Minimum thickness of the concrete shall be two inches over to top plane of the steel centering.

Caution: Do not use calcium chloride or additives containing salt in the concrete when used over galvanized sheets.
"U" Factor Table (includes Built-up Roofing)
Thick.
of
Concrete
over
Top of
Corrug.		 Wt. Lbs./
Ft.2
Metal
and
Concrete		 Depth of Corrugation
9/16" -- 28 Gauge		 Wt. Lbs./
Ft.2
Metal
and
Concrete		 Depth of Corrugation
7/8" -- 26 Gauge		 Wt. Lbs./
Ft.2
Metal
and
Concrete		 Depth of Corrugation
1 5/16" -- 24 Gauge
No Ceiling
Heat Flow		 Ceiling
Heat Flow		 No Ceiling
Heat Flow		 Ceiling
Heat Flow		 No Ceiling
Heat Flow		 Ceiling
Heat Flow
Up Down Up Down Up Down Up Down Up Down Up Down
2" 5.56 .22 .20 .12 .11 6.21 .20 .19 .11 .11 6.98 .19 .18 .11 .11
2 1/2" 6.60 .19 .17 .11 .10 7.25 .18 .17 .10 .10 8.02 .17 .16 .10 .097
3" 7.64 .16 .15 .099 .096 8.29 .16 .15 .097 .093 9.06 .15 .14 .093 .090
3 1/2" 8.68 .15 .14 .092 .089 9.33 .14 .13 .090 .087 10.10 .13 .13 .087 .084
4" 9.72 .13 .12 .083 .083 10.37 .13 .12 .084 .081 11.14 .12 .11 .082 .079
Notes:
  • FT.2 above (in Wt. Lbs./ Ft.2 Metal and Concrete) is square feet.
  • Add 6 lbs. per sq. ft. for built-up roofing.
  • Ceiling used in "U" value calculators is 1/4 Fiberglas lay-in panel.
  • Authority for "U" values based on ASHRAE Guide and test data by recognized independent laboratories.
  • Weights and "U" values may vary slightly dependent on corrugation depth variance of each sheet manufacture.