Waterproofing Code: Backfill
FOOTINGS AND FOUNDATIONS
The backfill in the annular space around columns not embedded in poured footings shall be by one of the following methods:
- Backfill shall be of concrete with an ultimate strength of 2,000 psi (13.8 MPa) at 28 days. The hole shall not be less than 4 inches larger than the diameter of the column at its bottom or 4 inches larger than the diagonal dimension of a square or rectangular column.
- Backfill shall be clean sand. The sand shall be thoroughly compacted by tamping in layers not more than 8 inches in depth.
- Backfill shall be controlled low-strength material (CLSM).
This section implies that backfill material shall be in accordance with code requirements. This section was originally contained in the Waterproofing and Dampproofing Section of the BOCA code. In its original form it addressed backfill around foundations—a pertinent component of a waterproofing application. Therefore, it provides relevance and requires addressing from a waterproofing perspective.
This section implies that the excavation outside of the foundation shall be backfilled with soil that is free of all organic material, construction debris and large rocks. The backfill shall be placed in lifts—no more than 8 inches in depth—and compacted or tampered in a manner that has no adverse effect or cause damage to the substrate or the waterproofing or dampproofing material.