Base counterflashing and reglet fabrication · Lesson 1 of 4

Base counterflashing and reglet fabrication: principles and terminology

The two pieces at a roof-to-wall joint, the two meanings of reglet and of base flashing, how the top edge is held, and where AFS work ends and site work begins.

You will be able to: Define base flashing, counterflashing, reglet, raggle and receiver in both the senses the trade uses, name the ways the top edge is held, and state the safety boundaries at the wall and in the shop.

13 min · 12 slides · 10 questions

All lessons in this module

Slide 1 of 12

Two pieces at one joint

Base flashing turns up the wall from the roof; counterflashing laps down over it from the wall above.

In the CDA details, counterflashing diverts water running down the wall onto the base flashing.

In the CDA details, the base flashing is designed to accommodate building movement.

This module covers both pieces and the reglet or receiver that holds the top of the counterflashing.

Sources

Copper in Architecture Design Handbook - 9.2 Counterflashing - Copper Development Association

Videos for this lesson

What this video shows: GAF's installation overview of a parapet wall flashing with a counterflashing detail for its TPO and PVC single-ply systems: here the base flashing is the roofer's membrane. A manufacturer detail.

Video: Parapet Wall Flashing with Counterflashing Detail | TPO Commercial Roofing | GAF Drawing 301 by GAF Roofing, on YouTube. Chosen from the video's published description.

What this video shows: GAF's installation overview of a termination at a rooftop unit with counterflashing, for its TPO and PVC systems: counterflashing used at a curb, not only at walls. A manufacturer detail.

Video: Termination at R.T.U. with Counterflashing Detail | TPO Commercial Roofing | GAF Drawing 503B by GAF Roofing, on YouTube. Chosen from the video's published description.

Glossary

Base flashing: The flashing at the joint between a roof and a vertical surface. In the CDA details and in this module, metal; to NRCA, plies or strips of roof membrane.
Counterflashing (cap flashing): The piece that laps down over the top of the base flashing and diverts water onto it.
Reglet: Either a groove in a wall for attaching counterflashing (CDA) or a sheet-metal receiver for it (NRCA). AFS's products and FlashDraft profiles named Reglet are metal parts.
Raggle: NRCA: a groove or slot often cut in a masonry wall, into which a component such as a reglet is inserted.
Receiver: NRCA: a component of a two-piece counterflashing, surface-mounted, set in a raggle or built in behind cladding.
Lead wedge: A wedge of rolled lead sheet (Levine: 4 lb lead) driven into a reglet to hold the flashing in it.