The last thing to install is the tack glue board. After backfilling around the vault, install a tack glue board around the vault’s perimeter. This allows you to securely attach the synthetic material in this area. The synthetic material rests on compacted field base soil and, depending on the specification, may be attached with tack nails, glue, or both.
The most common tack glue board construction material is Trex™ 2" x 4" (50 mm x 100 mm) lumber. A close-fitting frame design is ideal. Install the tack glue board around the vault’s exposed upper rim with adhesive between the frame and vault. It should be equal in elevation to the vault’s perimeter rim.