Roofing Code: Chapter 15

Roofs and Roof Structures

Section 1504.1, Wind Resistance of Roofs

Roof decks and roof coverings shall be designed for wind loads in accordance with Chapter 16 and Sections 1504.2, 1504.3 and 1504.4.

Code Interpretation

This section implies that wind-engineering calculations should be completed for all roofs. Section 1603.1.4, “Wind Design Data,” states, “The following information related to wind loads shall be shown, regardless of whether wind loads govern the design of the lateral-force-resisting system of the building.” Wind design calculations should be completed in accordance with FM or ANSI and shall include the following criteria:

• Basic wind speed (3-second gust), miles per hour (km/hr).

• Wind importance factor and occupancy category.

• Wind exposure; if more than one wind exposure is utilized, the wind exposure and applicable wind direction shall be indicated.

• The applicable internal pressure coefficient.

• Components and cladding. The design wind pressures in terms of psf (kN/m2) to be used for the design of exterior component and cladding materials not specifically designed by the registered design professional.

This section also implies that each roof covering

- clay and concrete tiles, as well as mechanically attached, adhered and ballasted low-slope systems

- should be applied in accordance with attachment methods for localized wind requirements.

Waterproofing Code: Section 1805

Footings and Foundations

1805.7.3, Backfill

The backfill in the annular space around columns not embedded in poured footings shall be by one of the following methods:

1. 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 (102 mm) larger than the diameter of the column at its bottom or 4 inches (102 mm) larger than the diagonal dimension of a square or rectangular column.

2. Backfill shall be clean sand. The sand shall be thoroughly compacted by tamping in layers not more than 8 inches (203 mm) in depth.

3. Backfill shall be controlled low-strength material (CLSM).

Code Interpretation

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, backfill requires addressing from a waterproofing perspective. It also 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 in a manner that has no adverse effect on the substrate or the waterproofing or dampproofing material.