N.Y.C. Admin. Code § BC 1804: Section BC 1804: Excavation, Grading and Fill

1804.1 Excavations near foundations.

Excavations for any purpose shall not reduce vertical or lateral support for any foundation without first evaluating if underpinning or protecting the foundation against detrimental lateral or vertical movement, or both, is required. Where required, underpinning or shoring shall be provided in accordance with Section 1817.

1804.2 Placement of backfill.

The excavation outside the foundation shall be backfilled with soil that is free of organic material, construction debris, or boulders. A controlled low-strength material (CLSM) can be used as backfill in lieu of soil. Soil backfill shall be placed in lifts and compacted in a manner that does not damage the foundation or the waterproofing or dampproofing material.

Exception: Controlled low-strength material need not be compacted.

1804.3 Surcharge.

No fill or other surcharge loads shall be placed adjacent to any building or structure unless such building or structure is capable of withstanding the additional loads caused by the fill or the surcharge.

Exception: Grading for landscaping purposes shall be permitted where done with walk-behind equipment where the grade is not increased more than one foot (304.8 mm) from original design grade, or where approved by the commissioner.

1804.4 Site grading.

The ground immediately adjacent to the foundation shall be sloped away from the structure as needed, or an approved alternate method of diverting water away from the foundation shall be used, where surface water would detrimentally affect the foundation material (soil and/or rock). Grading shall not be detrimental to the bearing material of adjacent structures. Site grading shall also comply with Section 1101.11 of the New York City Plumbing Code.

1804.4.1 Seepage.

In an excavation where soil and groundwater conditions are such that an inward or upward seepage might be produced in materials intended to provide vertical or lateral support for foundation elements or for adjacent foundations, excavating methods shall control or prevent the inflow of ground water to prevent disturbance of the soil material in the excavation or beneath existing buildings. No foundation shall be placed on soil that has been disturbed by seepage unless remedial measures have been taken.

1804.5 Grading and filling in flood hazard areas.

Grading and/or filling in areas of special flood hazard shall not be permitted except as permitted in Appendix G.

1804.6 Compacted fill material.

Where foundations will bear on compacted fill material, the compacted fill shall comply with the provisions of a geotechnical report prepared, signed and sealed by the engineer, which shall contain the following:

1. Specifications for the preparation of the site prior to placement of compacted fill material.

2. Specifications for material to be used as compacted fill.

3. Test method(s) to be used to determine the maximum dry density and optimum moisture content of the material to be used as compacted fill.

4. Maximum allowable thickness of each lift of compacted fill material.

5. Field test method(s) for determining the in-place dry density of the compacted fill.

6. Minimum acceptable in-place dry density expressed as a percentage of the maximum dry density determined in accordance with Item 3.

7. Number and frequency of field tests required to determine compliance with Item 6.

8. Acceptable types of compaction equipment for the specified fill materials.

1804.7 Controlled low-strength material (CLSM).

Where footings will bear on controlled low-strength material (CLSM), the CLSM shall comply with the provisions of a geotechnical report prepared, signed and sealed by the engineer, which shall contain the following:

1. Specifications for the preparation of the site prior to placement of the CLSM.

2. Specifications for the CLSM.

3. Laboratory or field test method(s) to be used to determine the compressive strength or bearing capacity of the CLSM.

4. Test methods for determining the acceptance of the CLSM in the field.

5. Number and frequency of field tests required to determine compliance with Item 4.