Galvanized steel pitch pan on a built-up roof with various conduit penetrations.

 

A group of large pitch pans on a PVC roof provide a seal around angled equipment supports.

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Basic Information: A pitch pan is type of roof flashing. Pitch pans look like open-topped boxes, rings, or cylinders made out of sheet metal (almost always galvanized steel) or a molded polymer. Pitch pans function as containers for the relatively large amount of sealant typically applied around roof penetrations to prevent water from passing through the penetration. Pitch pans are used to flash roof penetrations which would be difficult to flash in any other way: small penetrations such as electrical conduits, irregularly-shaped penetrations such as I-beam supports, or multiple penetrations very close together. They are also called pitch pockets, penetration pockets, or sealant pockets.

Pitch pans are notorious as a source of leaks. Sealant shrinks and degrades over time, leading to eventual leaks. The item being flashed by the pitch pan may vibrate or shift in the wind and break the seal, especially as the sealant gets older. The relatively small flange commonly found on metal pitch pans makes it difficult to provide an adequate tie-in with the roof membrane; failed stripping is another source of leaks at pitch pans.

Because of these issues, pitch pans should be a high priority during preventative maintenance inspections, and should be checked twice a year. Inadequate sealant should be topped off immediately.

A pitch pan should be considered a flashing of last resort. At curbed HVAC units, conduit lines should be routed down into the building inside the curb, underneath the unit, if possible. A gooseneck penetration flashing is preferable to a pitch pan, and can accommodate flexible conduits or cables.

 

Construction detail for a pitch pan to be installed on an EPDM roof.

 

Useful Links:

  1. General: For a look at some retail-available prefabricated pitch pockets, see these pitch pockets on Amazon, or this page at the Home Depot.*

2. General: “Manual Elements: Penetration Pockets” is a short, decent introduction to pitch pans. From 2005, archived on the Professional Roofing magazine website.

3. General: Reasonable concerns and advice regarding pitch pockets can be seen over on Architekwiki. Don’t let “Pitch Pockets” scare you too much.

4. Building Codes: Pitch pans are not specifically mentioned in the model building codes of the International Code Council, but they are broadly covered by 1503.2 Flashing in the International Building Code and R903.2 Flashing in the International Residential Code. To see language in a building code that has been amended to mention pitch pans specifically, see 1514.2.5 Roof Penetration Flashing from the 2017 Florida Building Code.

5. Technical: See this product data bulletin for assembly and installation instructions for basic galvanized steel pitch pans. On the R. M. Lucas Co. website.

6. Technical: See this product data sheet for technical information about precast, non-sheet-metal (in this case, polyester resin) pitch pockets. On the Chem Link website.

7. Technical: See this product data sheet for technical information about pitch pans made from injection-molded TPO, intended for use with TPO roof systems.On the Johns Manville website.