McNICHOLS Trench Drain System: New Construction Installation

There are 6 steps to the New Construction installation process. See below for details.

Main Installation Diagram
   Trench Drain System New Construction

Note: All reinforcement bar details and expansion joints are to be developed by the slab designer. Trench drain must not be used as an expansion joint, construction joint, or control joint.

Kit Contents
Kit Contents
Kit Number 1 2
Run Length (Feet) 20 40
# of Channels 5 10
# of Grates 10 20
# of Locking Devices 11 21
# of Installation Chairs 7 12
# of End Caps 2 2
# of Grate Bags 10 20

Tools Required
· 1/2" Wrench or Socket   · 9/16" Wrench or Socket   · Hammer
· Level   · String Line   · Duct Tape
· Tin Snips

McNICHOLS Standard Chair Installation
(Secure chair in bottom dimples on the channels)

Trench Drain System New Construction

Step 1: Excavation and System Layout
The subbase must be excavated sufficiently to ensure a minimum of 4 inches of concrete cover underneath (or an amount equal to the slab thickness, whichever is greater) and on both sides of the finished drain system. Slope the edges of the excavation to provide a smooth transition to the slab subgrade. Slope the bottom of the excavation to approximately follow the slope of the channels. The excavation should be made along the centerlines of all the proposed drainage runs. Prepare a deeper excavation for all appropriate catch basins (if used) to ensure a minimum of 4 inches of bedding concrete underneath. Once the excavations are complete, place all of the required components (in the correct order) next to the excavation. It is often helpful at this point to set an alignment "string line" over the proposed trench run to indicate the finished grade elevation.

Step 2: Catch Basin Installation (Optional)
The catch basin should be located near the discharge piping stub-in. Carefully drill out the cutouts which correspond to the desired pipe size to be used. Make the appropriate discharge pipe connections. Place the catch basin into the excavation and support it with bricks. Place the bedding concrete into the catch basin and level it to the correct surface elevation.

Note: Do not remove channel knockouts at this time. (See step 6)

Step 3: Channel Installation
Begin the installation of the channels at the discharge end of the trench run with the deepest (highest number) channel. If a catch basin is being used at the discharge point, connect this channel to the catch basin (the arrow always points downstream). If a catch basin is not being used, attach the proper end cap to the discharge end of the channel. If a channel "bottom cutout" is being used, remove the appropriate size and install the channel over the outlet drain stub-in. The succeeding channels should be installed with the Installation chair under the channel at the channel joints being connected. Tighten the chair alignment bolts into channel dimples. Place the precut rebar (minimum 1/2 diameter #4) through rebar connecting clamps. Drive the rebar into the subgrade enough to provide stability and prevent floating during concreting. Adjust the chair, raising the channel to the string line height, and secure the rebar clamps.

Note: The top of the rebar should be a minimum of 2 inches below the finished grade.

Step 4: Grate/Frame Installation
The proper grate must be secured in the channels prior to concreting to prevent the channels from flexing inward from the pressure of the wet concrete. Grates should be wrapped in plastic grate bags (included) prior to installation to facilitate cleanup after concreting and to provide adequate spacing for grate removal. Care must be taken not to spread the channel walls.

Note: Set the grates (and frames, if applicable) into the channel and install the locking devices.

Step 5: Concreting
After the placement of the system at the proper grade has been completed, check to ensure that the channels will not "float" when the concrete is placed. When installed properly the Installation Chair will prevent "floating" by its positive engagement into the sides of the channels. Consideration should be given for the use of reinforced steel in the concrete beam which encases the system. The type of reinforcing must be determined by the slab designer. When placing the concrete, be sure it is placed under the channels and is properly consolidated. The concrete that is placed under and around the channels may be placed as part of a monolithic slab pour.

Note: The frames, if used, will float off the channel unless they are properly secured in place with a grating and locking device.

Note: The drain system must not be utilized as an expansion joint, control joint or construction joint.

Parallel slab joints should be formed no closer than 6 inches from the edge of the system or a distance equal to the slab thickness, whichever is greater. When expansion joints are perpendicular to and intersect the system, an expansion joint must be incorporated in the drain system. Use the installation chair to support the ends of the channels at this location, but do not engage the alignment bolts (it takes 2 chairs at the expansion joint). After completing the slab pour, concrete finishing should proceed in the usual manner.

Note: Do not tool finish or radius the edge of the concrete along the drain channels. Finish-trowel only to the top edge of the drain channels.

Step 6: Clean Up
After the concrete slab is hard enough to walk on, remove the wrapping from the grates. Remove the catch basin channel knockouts at this time.

Note: To minimize spalling, use a small hammer to tap out the knockout from inside the catch basin. Clean out any debris in the system and be sure that the outlet pipes are clear. Install accessories such as strainers, trash baskets, etc. Reset and lock down all grates in the proper position. The system is now ready for service.