Category talk:605 Underdrainage
Our office has found what appears to be a conflict between the Standard Plans and the current online spec book.
The standards show that the type 1/5 base placed on top of the underdrain. The spec states that the type 1/5 is to be placed and compacted first. Since the EPG, says to review the Standard and spec prior to installation. The two of these need to agree or be clearified.
605.10.2.2 Trenching, placement, and backfill of underdrains shall be performed only after Type 1 or Type 5 base is placed and compacted. Backfill material shall be compacted by three passes of a vibrating pad or drum-type compactor approved by the engineer.