Does BOMA Adjust for Sloped Walls?

BOMA

• Local affiliates represent BOMA, an international advocacy organization. BOMA reviews and advises on matters that impact property owners and managers. Together with the American National Standards Institute, BOMA has developed standards to measure space, prorate common areas and establish rentable area figures. BOMA standards have been prepared for a variety of buildings, such as office, industrial, and multi-unit residential, and they're a widely accepted method for calculating leasing space.

Usable Area and Rentable Area

• Tenants occupy a certain amount of space, but they also share common areas with other tenants. In the BOMA standard, usable area is the measured area of the actual space that tenants use. The standard also prorates lobbies, corridors, washrooms and other shared spaces, and combines the prorated figure with the occupied space total, referred to as rentable area. The rentable area of a building doesn't change unless the size of the building changes.

BOMA Measurements

• Measurements using BOMA criteria are taken for wall, ceiling and floor surfaces prepared for tenant use, excluding the thickness of finishing material, such as paneling and carpet. Stairs, elevator shafts, flues, pipe shafts and vertical ducts, and the walls that enclose them, that serve more than one floor of the building, are noted as major vertical penetrations. Construction details that impact on the usable space, such as sloped walls, are handled with the dominant portion measurement.

Sloped Walls

• The dominant portion is the part of the inside finished surface of the permanent outside wall that amounts to 50 percent or more of the floor-to-ceiling measurement. When a wall slopes, the dominant portion is measured to where the slope begins. If it slopes inward, it reduces the amount of space that can be occupied. If the slope is outward, the floor space ends at the bottom of the slope.