Trench Former Pre-sloped Trench Drain System


Trench Former® by ABT, Inc., is a pre-engineered, cast-in-place concrete forming system for forming drainage trenches, catch basins, utility chases and voids in concrete placements. Consisting of expanded polystyrene (EPS)form sections, embedded steel inlay rails with our patented no-float legs, and grates. The system eliminates the need for heavy forming materials, keyways and waterstops normally required with trench drains and utility chases.

Standard Design

TFX-12 former shapes are made from lightweight expanded polystyrene (EPS) to provide the most widely used trench size, 12″ wide with a 1.04% built-in slope and radius bottom.

Custom Design

Trench Former is available in various widths, depths, slopes, and trench bottom configurations.

Precision Engineering

Precision is engineered into the product, eliminating the need for highly skilled and expensive labor. Accurate to within 1.5mm (1.16 in.), the former shapes have longitudinal grooves for alignment, and integral deforming grooves for easy removal.

Low Cost

The Trench Former System requires no heavy machinery (except for excavation) and is in place a fraction of the time of previous methods, reducing installed costs by 33% or higher.

Easy Installation


A non-structural anchoring slab placed over the no-float legs holds the formwork firmly in place without elaborate anchoring. Concrete can then be placed monolithically, eliminating cold joints, keyways, and waterstop material between the trench floor and walls. Forms can be removed in 24 hours or can be left in place indefinitely, preventing unsafe open pits on the job site. There are no piping alignment problems because piping is butted to the formwork and cast-in-place.

Environmentally Sound

The EPS forms are manufactured without CFC’s and can be disposed of safely and easily. It’s also recyclable and makes a high quality fuel for commercial incinerators as well as being landfillable.

Low Maintenance

The permanent system components are designed to be maintenance friendly. Quarterly inspections are recommended, but the built-in slope, radius bottom, and low roughness coefficient help to eliminate debris buildup.


TFX-12 has revolutionized drain trench installation and performance. Check out the differences between TFX-12 and hand forming.

TFX-12 is the standard stock Trench Former system. Its components are made in the most commonly constructed size trench drain. TFX-12 consists of 2.4 m (8 ft.) pre-sloped form segments. The 21 stock segments can be used together to create a continuously sloped 51 m (168 ft.) trench. Each segment is engineered to a 10.4 mm per meter (1/8 in. per ft.) slope (1.04%). The EPS forms create 305 mm (12 in.) wide trenches with a 165 mm (61/2 in.) radius bottom and a 356 mm (14 in.) grate seat area. They have integral deforming grooves for easy removal and full length longitudinal grooves for copla­nar rail spacing and alignment. Six non-sloping, 1.2 m (4 ft.) or 2.4 m (8 ft.) long forms are available throughout the system to create longer continuous runs.

The steel angle rails include anchoring studs welded on 280 mm (11 in.) centers to the outside cor­ners. 12 mm (1/2 in.) threaded U-shaped no-float legs attach to horizontal tabs on each rail. Each rail end is designed to accept a rail alignment clip which connects adjacent rail segments. Prefabricated L-rail and T-rail assemblies allow for field installation of 90° turns anywhere in the pre-sloped layout.

Outlet piping is butted to an angular groove made in the EPS form prior to concreting. For trench junctions or for large outlet sizes, four catch basins are provided. A wide selection of retainable grates and solid covers is available for various loadings.


45 x 45 x 4.5 mm (1 ¾” x 1 ¾” x 3/16” in.) structural steel rails are manufactured in five lengths: 2.4, 1.8, 1.2, 0.9 and 0.6 M (8, 6, 4, 3 and 2 ft.). The ends of all the rails are punched to receive the alignment clip and have tabs on which to mount the no-float legs and cross ties. Anchor studs are welded on 280 mm (11 in.) centers. The selection of rail sizes lets you meet any desired trench layout to within 150 mm (6 in.) without modification. Standard rail components are a powder coated black epoxy paint and are also available in hot dip galvanized if required.

Part# 1492 (2 ft.)
Part# 1493 (3 ft.)
Part# 1494 (4 ft.)
Part# 1496 (6 ft.)
Part# 1498 (8 ft.)

No-Float Legs

The seven no-float leg sizes are color coded to match their corresponding form sections for easy installation. This patented feature is at the heart of the
Trench Former no-float guarantee. Legs are secured to rails by two 18 mm (3/4 in.) nuts for stability and strength.

EPS Forms

Our EPS forms include unique deforming grooves which keep the foam segments together during the concrete pour, and alignment slots in the top which are sized
for a standard 2 x 4. Each 2.4 m (8 ft.) pre-sloped length has a radius bottom and a built-in 1.04% (1/8 in./ft.) slope. Non-sloping lengths are 1.2 m (4 ft.)
and 2.4 m (8 ft.). Part numbers are marked on the deep (down­stream) end in the color that matches its corresponding no-float U leg.

End Rails

End rails close off the end of a trench run preventing concrete from entering the end of a trench. Alignment clips will also slide onto rails that have been cut during fabrication.

Part# 1498EF

Former Release

Former Release is a non-petroleum based product which is to be applied to all EPS forming surfaces. It provides good concrete release properties without attacking EPS
foam and is available in one and five gallon cans. Form Release is best applied with a brush.

Part# 1336 (1GL)
Part# 1336 (5GL)

Grate Locking Devices

Lock toggles tie down grates by turning against the trench wall and securing to the underside of the steel rail.

Assembly# 1811A (Fits 1500.14, 1502.14, 1503.14 and 1504.14)
Assembly# 1811B (Fits 1502.14)
Assembly# 1887 (Fits 1468.14)


Slotted Grate

Part# 1502.14
Load Class 31.2
AASHTO H-25 Rated Yes
Material Ductile Iron
Open Area 65%
Dim (LxWxT) 18 x 13.78 x 1.5
Weight 26.0 lbs.

Slotted Grate (Heavy Duty)

Part# 1503.14
Load Class 90.0
AASHTO H-25 Rated Yes
Material Ductile Iron
Open Area 41%
Dim (LxWxT) 18 x 13.75 x 1.5
Weight 60.0 lbs.

Pedestrian (ADA) Grate

Part# 1504.14
Load Class 9.4
AASHTO H-25 Rated Yes
Material Cast Iron
Open Area 22%
Dim (LxWxT) 18 x 13.75 x 1.5
Weight 50.9 lbs.

Trim Banded Bar Grate

Part# 1468.14
Load Class 3.7
Fed. RR-F-624E Ped Yes
AASHTO H-20 Rated No
Material Galvanized Steel
Open Area 88%
Dim (LxWxT) 24 x 13.75 x 1.5
Weight 18.6 lbs.

Solid Cover

Part# 1500.14
Load Class 16.6
AASHTO H-25 Rated Yes
Material Cast Iron
Open Area 0%
Dim (LxWxT) 18 x 13.75 x 1.5
Weight 55.3 lbs.

1900 Series Catch Basin

The 1900 series catch basins are 350 mm (14 in.) wide x 610 mm (2 ft.) long flat bottom units, manufactured in 610 mm (2 ft.) and 915 mm (3 ft.) depths. They utilize 610 mm (2 ft.) long rail (#1492), standard trench grates, locking devices, and end rails.

Part# 1900 (2 ft. deep)
Part# 1901(3 ft. deep)

1600 Series Catch Basin

The 1600 series catch basins are 610 mm (2 ft.) x 610 mm (2 ft.) and are available in both 610 mm (2 ft.) and 915 mm (3 ft.) depths. This series uses two 610 mm (2 ft.) long frame rails (#1492) and two end rails (#1492EF). Frame rail components clip together with no addition­al hardware required.

Part# 1610 (2 x 2 x 2 ft.)
Part# 1611 (2 x 2 x 3 ft.)

TrenchFormer Downloads