HVAC – What Is An Adjustable Pitch Curb?

Have you ever notice a rooftop which was not flat, but angled? Of course, we all have. Now imagine you must install a HVAC Rooftop Unit (RTU) on to the roof.

Perhaps you’re thinking, so what if the RTU is angled on the roof. Valid statement. Valid, but problematic… for starters HVAC rooftop units are designed to externally drain internal condensation, depending upon the angle, this could cause the condensation to collect and leak into the building, or cause rust issues by collecting on internal components.

The primary factor is weight distribution. A Roof Curb is designed for the weight of a RTU to be distributed directly downward. If you set a flat curb on an angled roof you are redistributing the weight disproportionately throughout the roof curb, and altering the RTU’s center of gravity. This could cause the roof curb to physically fail, and the RTU to fall off the rooftop; especially in storm and wind conditions which would pose little to no danger to a well seated, flat lying curb.

A Fixed Pitch Curb

Often when choosing a pitched curb, a specific fixed angle “Welded Pitch Curb” must be custom ordered. The pitch angle of the roof must be measured, and the exact placement and orientation of your RTU’s supply & return must be considered.

The Adjustable Pitch Curb is designed to pitch in any direction, and ships knockdown. It is less expensive than a fixed welded pitch curb, and offers job-site flexibility. All MicroMetl Adjustable Pitch Curbs are designed to pitch up to 1 in 12 inches in any direction. Meaning they will set level on a roof which the roof pitch increases, or decreases 1 inch in height, for every 12 inches of roof extension or run.

The Adjustable Pitch Curb allows an installer to inventory less curbs, allows job site flexibility, and reduces wait time from manufacturing, while offering peace of mind knowing the incorrect “Welded Pitch Curb.” won’t be mistakenly ordered.

Adjustable Height – The Added Bonus

Most manufacturers construct a standard height 14 inch tall curb. Other standards (speaking specifically of MicroMetl), often consist of an 8, 11, 14, and 24 inch fixed height curb. Therefore, if you desire a height outside of the standard, you will experience a slight premium for breaking the standard. The Adjustable Pitch Curb can save you the additional cost by acting as an Adjustable Height Curb.

Therefore, the same curb you could inventory for a pitched roof can save you money by allowing height requirement flexibility. Because the curbs are designed for a maximum of 1 in 12 inch pitch, the height adjustment will vary from curb to curb. Please feel free to contact the MicroMetl Customer Service Department to verify height requirements, or post your questions on our Open Forum!