ABT, Inc. • PO Box 837 • 259 Murdock Road • Troutman, NC 28166
(800) 438-6057 • (704) 528-9806 • Fax: (704) 528-5478

> PolyDrain > Installation > PolySeat Method

Installation with PolySeat Installation Chairs

Note: PolySeat Installation Chairs are not well suited for use in compacted stone base, soils containing large gravel, cobbles or sandy soils.

Excavate trench.
Set a stringline to finished slab height at the outside edge of the proposed channel location. Use this stringline to align the flat vertical sides of the channels.
Lay out channels as perviously described.
Begin channel installation at the trench outlet (downstream end) using two PolySeat Installation Chairs per channel. Set screws for both PolySeats should be on the same side of the channel.
Measure and record the distance from the top of the first channel (A) to the anchoring rib (B) at both ends of the channel. These measurements will vary with each channel.
Set two PolySeats into the soil approximately 8" and 32" from the end of the trench run. A short section of 2 x 4 placed between the chair uprights should be used to drive the PolySeats. Align the outermost surface (hook) of the PolySeat with the stringline as it is being driven into the soil. This will ensure that the chairs are properly aligned to receive the channels. The distance between the hook and the stringline should be equal distances measured in step five minus 1/2 inch. This will result in the top of the channel being slightly above finished elevation. The adjustment to final depth will be made once the channel has been inserted into the chair.
Set the channel into the PolySeat. Place the 2 x 4 across the top of the channel above the PolySeat and tap down, alternating from end to end, until the channel is at final grade. Allow 1.2" for additional depth of frame, if required. Tighten the set screws on the PolySeats.

With the first channel properly positioned, set a 3" Schedule 40 PVC pipe into bottom of channel, allowing the pipe to protrude from the upstream end of the channel approximately 8".
Drive next PolySeat Installation Chair into the soil so that the upper crossbar is 3/4" below the bottom of the PVC pipe. Set net PolySeat into soil approximately 24" in line from first PolySeat in the same manner. The pipe follows the built-in slope of the channel, so PolySeats will be positioned to the proper depth for the next channel.
Seal joints with appropriate sealant if required. Place PolyDrain channel into PolySeat. Tap down to final grade and butt channel ends flush with each other.
Repeat this procedure until all channels are properly positioned.
Place concrete around and under channels, filling the entire trench to slab depth. Concrete placement should be done so that the flow is not directed at PolyDrain channel walls as this could compromise alignment.
Finish concrete and secure grates into channels.