Flash a Plumbing Vent or Roof Penetration

A. Finished-Work Specification

Deliverable: one compatible flashing boot or curb installed over one authorized roof penetration, integrated course-by-course with the underlayment and asphalt-shingle field, fastened and sealed only at manufacturer-approved locations, with surrounding shingles cut neatly and drainage preserved over the flange, supported by a completed local water-path observation and flashing record.

B. Governing Documents

Document	Confirmed Current	Notes
Approved penetration location and framing clearance
Pipe or curb size specification
Flashing product manufacturer instructions
Roof-slope range for the selected product
Material compatibility and service-temperature rating
Chapter 1 roofing-readiness decision

C. Acceptance Standards

Check	Standard
Penetration authorization	Confirmed secured, plumb where required, and extended to the specified height; matches framing and ventilation plans
Flashing product selection	Matches pipe diameter, roof slope, roofing type, climate, and service temperature per manufacturer instructions
Shingle integration	Lower flange over lower shingles; upper flange beneath upper shingle courses; full drainage preserved over the flange
Fastening	Located only at manufacturer-approved zones; no fasteners in the exposed lower flange or exclusion zone
Sealant	Applied only at exposed or designated fastener locations using a compatible product; no excess sealant substituting for laps
Shingle cuts	Neat, close enough to support the flashing without binding the collar, no unsupported narrow strips
Verification	Local water-path observation or hose test completed only when permitted and safe, and not represented as a whole-building test
Documentation	Penetration type, flashing product, integration sequence, fasteners, sealant, and test limits recorded before the area is considered complete

D. Required Project Sequence

1. Review the approved penetration location, roof-framing clearance, pipe or curb size, flashing product, roof-slope range, temperature rating, material compatibility, and manufacturer instructions. Confirm each document's revision or date before using it as a reference and record it on the Governing Documents table.
2. Confirm that the penetration is authorized and does not require unapproved cutting of rafters, trusses, or structural decking. Compare the penetration location and framing clearance to the Chapter 1 readiness record and the current framing plan. Stop work and route to the responsible authority if the penetration does not match.
3. Verify the pipe, vent, or penetration is secured, plumb where required, and extended to the specified height. Measure the extension height against the approved specification and correct or refer any deficiency before flashing.
4. Inspect the surrounding deck, underlayment, membrane, and shingle courses for damage or contamination. Record any deficiency and correct only what is authorized before proceeding.
5. Select the correct flashing boot or curb for penetration diameter, roof slope, roofing type, climate, and service temperature. Reject a boot outside the manufacturer's stated fit range for the measured pipe diameter.
6. Dry-fit the flashing and mark the shingle and underlayment integration limits. Use a chalk line to mark the cutline on the surrounding shingles before removing the flashing.
7. Extend or patch self-adhered membrane around the penetration where required by the approved detail. Lap new membrane over the existing membrane in shingle-lap order, low to high.
8. Install lower shingle courses up to the penetration. Maintain the established exposure and offset pattern from Chapter 6 layout lines.
9. Cut the lower shingles closely enough to support the flashing without binding against the pipe. Use the utility knife and the marked cutline; do not leave a gap that would leave the flashing unsupported.
10. Slide or place the flashing over the penetration without tearing the boot or deforming the flange. Seat the boot collar fully against the pipe before positioning the flanges.
11. Position the lower flange over the lower shingles and the upper flange beneath the upper shingle courses. Confirm the shingle-lap relationship before fastening: lower flange on top of lower shingles, upper flange underneath upper shingles.
12. Fasten the flashing only at manufacturer-approved locations using compatible roofing fasteners. Keep fasteners out of the exposed lower flange and any zone identified as an exclusion zone.
13. Seal exposed or designated fasteners using the approved compatible sealant. Apply sealant only where the manufacturer specifies; do not use sealant as a substitute for the flange lap itself.
14. Install side and upper shingles around the flashing while preserving full drainage over the flange. Maintain the established exposure and offset pattern and confirm each course laps correctly over the upper flange.
15. Keep nails out of the exposed lower flange and prohibited water-path zones. Recheck fastener locations against the exclusion zone before covering them with the next course.
16. Cut shingles neatly without leaving unsupported narrow strips or blocking the boot collar. Verify the collar remains clear and functional after all surrounding shingles are trimmed.
17. Install storm collars, counterflashing, clamps, or accessory seals where specified. Follow the manufacturer's installation sequence for each accessory.
18. Inspect for cracked boots, improper fit, reverse laps, exposed fasteners, blocked drainage, open upper corners, and excessive sealant. Correct any defect found before proceeding to the verification step.
19. Perform the approved local water-path observation or hose test only when permitted and safe. Limit the observation to the penetration area and record the test duration and conditions.
20. Correct defects and repeat the local inspection. Reinspect the corrected area using the same standard as the original check.
21. Photograph and record the penetration type, flashing product, integration sequence, fasteners, sealant, and test limits. Attach photographs to the flashing record before the assembly is considered complete.