TinnerFlow™3rd YearRoof Work & CurbsYELLOW · Check First
A Doghouse is a vertical sheet metal enclosure built on a roof to house large horizontal duct transitions entering the side of a mechanical penthouse or building wall.
A Doghouse is a vertical sheet metal enclosure built on a roof to house large horizontal duct transitions entering the side of a mechanical penthouse or building wall.
To flash it, install an overhanging counter-flashing hood (shingle-style) above the duct penetration point. Run the lower sheet metal edges out over the roofing membrane so water sheds away from the opening like an umbrella canopy.
Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.