TerraDrain® C-56

TerraDrain® C-56 prefabricated chimney drains are constructed by fully wrapping a moderate strength, moderate flow capacity, formed polystyrene perforated core with a nonwoven filter fabric. The filter fabric is bonded to the core to prevent soil intrusion into the flow channels while allowing water to freely enter the drain core from both sides.

TerraDrain® C-56 chimney drains are available in 12”, 16” and 24” widths and provide a time saving, effective drainage solution for reducing hydrostatic pressure against retaining walls where full wall coverage is not required or is not feasible.

All values provided are intended for rapid comparison purposes, only. Please refer to a specific product’s Product Data Sheet (PDS) and the disclaimers therein for a detailed listing of all characteristics, associated definitions and values needed for structure design, specification compliance review and product submittal purposes. Please Download PDS for all information transfer, printing and submittal purposes.

Property Test Method English Metric


Material 1
Water Flow Rate
ASTM D4491 110 gpm/ft2 4483 Lpm/m2
Grab Tensile Strength
ASTM D4632 160 lbs 0.712 kN
CBR Puncture Resistance
ASTM D6241 450 lbs 2.00 kN
Apparent Opening Size
ASTM D4571 70 US Std. Sieve 0.210 mm
ASTM D4491 1.8 sec-1 1.8 sec-1
Grab Elongation
ASTM D4632 70 % 70 %
UV Resistance
ASTM D4355 70 % @ 500 hrs 70 % @ 500 hrs
AASHTO M 288-06 2
Survivability Class 2 Class 2


Material 1
ASTM D1777 0.25 in 6.35 mm
Compressive Strength
ASTM D1621 9000 lbs/ft2 431 kPa
Flow Rate 3
ASTM D4716 12.5 gpm/ft 155 Lpm/m

  • 1   PP = Polypropylene; HIPS = High Impact Polystyrene
  • 2   AASHTO Designation: M 288-06 Standard Specification for Highway Applications; American Association of State Highway and Transportation Officials, 2006. Geotextile survivability classification from installation stresses in subsurface drainage applications.
  • 3   In-plane flow rate measured at 3,600 psf (172 kPa) compressive load and a hydraulic gradient of 1.0.