A curb is a structural frame or raised base that elevates HVAC equipment above the roofline, preventing water accumulation and improving drainage around installations. Curbs typically stand 12 to 24 inches above the roof surface and include integral flashing that integrates with roof membranes. Proper curb installation is critical to preventing water infiltration and extending equipment service life by 5 to 10 years.
Construction Standards
Curbs are fabricated from galvanized steel, aluminum, or stainless steel with wall thicknesses of 0.075 to 0.125 inches. Roof curbs must support equipment loads up to 150 pounds per square foot plus wind forces up to 120 mph. Integral flashing must extend 12 to 18 inches across the roof deck and include secondary drain provisions.
Installation Benefits
Curbs eliminate standing water that causes premature corrosion, reducing maintenance costs by 20 percent. Proper curb installation improves ventilation airflow around equipment coils by 15 to 25 percent, enhancing cooling efficiency. Secondary drain pans and drain lines provide protection against catastrophic water damage to interior ceilings and equipment below.