Underground, Fiberglass,
Reinforced, Plastic Duct Work
877-608-4383
Have a representative contact you today

Please fill out this form completely and a representative will contact you shortly









An Underduct Sales Representative will contact you shortly.

Fiberglass Duct Installation

Underground Burial Procedures


FRP duct installation schematic
UnderDuct FRP should be laid in a graded trench with good drainage on a 4” bed of pea gravel. Minimum distance from under the slab to top of duct is 4" of compacted fill. The recommended maximum is 4' of compacted fill. Duct can be disgned for deeper burial. 

Encasement in concrete is not necessary. With fiberglass boots in place and sealed, cover with sand or pea gravel and pour floor slab with no delay or tie down. 

Duct is manufactured with a resin rich veil on the OD to prevent water infiltration.  Where ground water infiltration is possible the field joints should be made using the wet lay-up method as described in the installation instructions.

NOTE: Leak test the system before backfilling.




FRP Underground Duct Installation