Base flashing, counterflashing and reglets · Lesson 2 of 4

Base flashing, counterflashing and reglets: materials, standards and design constraints

Which document decides each number at a roof-to-wall joint: code, project specification, roof manufacturer and reglet manufacturer. Metal minimums, heights, laps, wedges and fills by source, reroofing reuse rules, and the OSHA silica and grinder rules for cutting reglets.

You will be able to: Name the documents that govern a roof-to-wall termination, compare the metal minimums, base flashing heights, laps, wedge spacings and fills they set, apply the reroofing rules for existing counterflashing, and state the silica and grinder rules that apply when reglets are cut.

9 min · 10 slides · 6 questions

All lessons in this module

Slide 1 of 10

Who governs the detail

Four documents can set the numbers: the adopted code, the project specification, the roof manufacturer's details and the reglet maker's instructions.

IKO's details say metal work should follow local code and/or project specifications and be reviewed and approved by a licensed design professional.

When they differ, the project documents name which one governs.

Sources

IKO detail T-T-9 Termination Bar at Tilt Up Panel Joint with Reglet Counter Flashing (issued 8/01/2025) - IKO Commercial
2021 Seattle Building Code, Chapter 15 Roof Assemblies and Rooftop Structures (IBC-based, locally amended) - City of Seattle, Department of Construction and Inspections
UFGS 07 60 00 Flashing and Sheet Metal (August 2023, Change 1 - 05/25), Part 3 Execution - U.S. Department of Defense, Unified Facilities Guide Specifications (Whole Building Design Guide)

Videos for this lesson

What this video shows: OSHA's short video on using the specified dust control method with handheld grinders for mortar removal, the Table 1 task closest to raking a reglet.

Video: Controlling Respirable Crystalline Silica: Handheld Grinders for Mortar Removal (Tuckpointing) by USDepartmentofLabor, on YouTube. AFS checked its description against this lesson.

What this video shows: OSHA's short video on using the specified dust control method with handheld power saws, as when a reglet is saw-cut in concrete or masonry.

Video: Controlling Respirable Crystalline Silica in Construction: Handheld Power Saws (Any Blade Diameter) by USDepartmentofLabor, on YouTube. AFS checked its description against this lesson.

Glossary

Lead wedge: A small wedge of rolled lead sheet tapped into a reglet to hold the counterflashing by friction; Levine says they are typically spaced 12 in on center, UFGS 07 60 00 allows up to 18 in apart.
Action level: In 29 CFR 1926.1153, an airborne respirable crystalline silica concentration of 25 micrograms per cubic meter as an 8-hour time-weighted average.
Table 1 (silica): The table in 29 CFR 1926.1153 that lists, task by task, the engineering controls, work practices and respirators an employer may use instead of measuring exposure.
Minimum flashing height: The lowest height the base flashing may stop above the finished roof surface; IKO's membrane details set 8 in (a manufacturer value, not a code number).