An equipment curb interrupts the roof assembly. Its support, opening, flashing, and service connections must work together; adding surface sealant cannot correct an unsupported or poorly detailed curb.

What to check first

  • Inspect curb corners and the upper flashing termination.
  • Check penetrations for refrigerant lines and wiring.
  • Leave deck openings, equipment support, and electrical work to the appropriate professionals.

Follow the connection from top to bottom

  1. Find the upper entry point

    Inspect where flashing ends against a wall, curb, pipe, or other surface. Water entering behind that termination may bypass a patch lower down.

  2. Correct the underlying defect

    Loose metal, rotten wood, failed fasteners, and deteriorated membrane need a suitable repair before waterproofing. A surface bridge needs stable, compatible material on both sides.

  3. Keep the detail functional

    A repair should shed water without blocking outlets, weep paths, or intended movement. Use the specified reinforcement and dimensions for the product and detail.

Watch the field examples

These archive demonstrations show individual projects. Use the current guidance above and Bergstrom’s published instructions if an older video shows a different product or method. Torch work shown in installation videos is professional work.

Watch Rooftop A/C Curbs: Plan the Opening and the Flashing TogetherOpens on YouTube ↗

From the project archive

Air Conditioner Curb Installation - Preparing where the roof will be cut for the A/C curb
Historical project photo · Flat Roof Doctor
A/C Curb Installation - Removing Insulation
Historical project photo · Flat Roof Doctor
Metal roof exposed under the rubber membrane and insulation
Historical project photo · Flat Roof Doctor

Product reference: Bergstrom Industries’ published knowledge catalog. Follow the latest product label and safety information. Historical project examples are educational and are not a specification for every roof.