Title: Roof-wall flashing: who owns the handoff | Cercha

Description: Assign roof-wall flashing before either crew starts. Use a responsibility table and a pre-siding check to coordinate roofing, siding, and gutters.

Canonical: https://cercha.pages.dev/guides/roofers-and-siding-crews/

# Roofers and siding crews: who flashes the wall

Working with trades

Assign each flashing operation in the subcontract, then inspect the connected water path before siding conceals it.

You are ready to roof an addition, but the siding crew expects someone else to finish the wall flashing. Agree on roof wall flashing responsibility before either crew finishes. Name who does each part, which detail they follow, and who checks it.

For asphalt shingles, [PNNL describes roofers installing step and kick-out flashing in coordination with house-wrap and siding installers](https://basc.pnnl.gov/resource-guides/step-and-kick-out-flashing-roof-wall-intersections). It also says the contract should assign the task to the appropriate trade for that job's workflow. Calling it roofing or siding work does not assign responsibility.

## Identify every roof-wall meeting point

Walk the elevations with the [roofer](/trades/roofing/) and [siding lead](/trades/siding/). Mark sloping sidewalls, roof ends against taller walls, dormers, porch intersections, and any nearby window. Give each location an identifier on a shared drawing. Make each junction easy to identify if someone misses it.

A sidewall runs beside the slope. A headwall crosses the upper end of a roof plane. Keep those details separate when requesting prices.

[PNNL's asphalt-roof guide treats flashing, underlayment, and roof covering as coordinated components](https://basc.pnnl.gov/resource-guides/asphalt-shingle-roofs). Do not transfer an asphalt detail unchanged to a metal or membrane roof.

Also identify where runoff leaves the wall. The kick-out detail belongs at the lower termination of the roof-wall junction. Trace the planned route through the gutter and downspout. [PNNL's gutter guidance connects roof collection with discharge away from the building](https://basc.pnnl.gov/resource-guides/gutters-and-downspouts).

Use the [trade handoff guide](/guides/trade-handoffs/) to turn that walk into a release between crews. A date on the schedule does not tell the next crew what is ready.

## Name who installs each layer

Use this worksheet to agree on scope. These proposed assignments do not set legal responsibility for a trade.

| Operation | Proposed owner to confirm | Evidence before release |
| --- | --- | --- |
| Select the assembly detail | Builder with designer and product support | Drawing and current instructions |
| Integrate roof underlayment and roof-side metal | Roofing contractor | Exposed installation photos |
| Install step flashing and lower kick-out | Roofing contractor, if included in its scope | Each junction checked before covering |
| Lap the wall drainage layer over flashing | Assigned WRB or siding installer | Visible continuity at the wall |
| Maintain siding termination and clearances | Siding contractor | Product-specific detail checked |
| Receive diverted water and finish discharge | Gutter contractor and assigned drainage trade | Connected path reviewed |
| Release the interface for concealment | Builder's named site contact | Dated acceptance and correction record |

Do not leave the wall-side operation inside a vague phrase such as “flashing by roofer.” Name who opens the WRB, who repairs it, and who returns if installation order changes. Record who supplies transition materials. For scope language, start with [inclusions and exclusions](/guides/inclusions-and-exclusions/).

[PNNL's drainage-plane guide explains that the wall's water-control layer must overlap exterior flashings](https://basc.pnnl.gov/resource-guides/drainage-plane-behind-exterior-wall-cladding). The worksheet must account for that overlap. If different crews install the layers, name who checks the connection.

## Agree on installation order before crews arrive

Bring the selected roofing and cladding details to the coordination meeting. Have both leads describe their installation order. Ask what each crew needs exposed when it arrives. Resolve an impossible sequence before materials reach the roof.

For shingle sidewalls, confirm how the flashing integrates with the roof courses and the wall drainage layer. Decide when the kick-out can be seen and checked. PNNL recommends inspection during installation, before later work hides the integration. [Its roof-wall guide illustrates the sequence](https://basc.pnnl.gov/resource-guides/step-and-kick-out-flashing-roof-wall-intersections).

Treat nearby openings as another interface. [PNNL's window and door guidance calls for flashing integrated with the wall drainage plane](https://basc.pnnl.gov/resource-guides/windows-and-doors-are-fully-flashed). If a window-head detail meets roof-wall work, put both details on the same marked elevation. Include the window installer in that discussion.

Do not use a generic online clearance dimension as the project's siding instruction. [James Hardie's architectural-panel guidance directs installers to the product instructions for clearance and flashing requirements](https://www.jameshardie.com/blog/for-siding-pros/how-to-install-hardie-architectural-panels/). Obtain the instructions for the actual product, assembly, and installation conditions. Ask the designer or manufacturer to resolve conflicts with the approved project detail.

## Check these items before siding starts

Inspect the water-control layers before crews cover them. Use safe access arranged by the responsible contractor. These are suggested coordination checks, not a substitute for required inspections or product instructions.

- Match each marked roof-wall location to the selected detail.
- Follow the wall drainage layer down onto the flashing.
- Confirm the intended laps continue through corners and terminations.
- Check that the kick-out outlet remains open and faces the planned collector.
- Look for torn WRB, damaged metal, displaced pieces, or later penetrations.
- Compare the planned siding termination with its installation instructions.
- Photograph the exposed junction and its location on the elevation.
- Identify any incomplete work and the person responsible for correction.

[PNNL's missing-flashing guide shows why roof-wall locations deserve a deliberate visual review](https://basc.pnnl.gov/diy-guides/look-missing-roof-and-wall-flashing). Inspect the junction itself. A wide photo of a finished roof does not show concealed laps.

Release only the checked locations. If the front porch is ready but a dormer remains incomplete, identify the open location in writing. Tell the siding lead which locations are ready and which must wait.

## Handle reroofs and siding replacements explicitly

For a reroof beside existing siding, agree on the removal and repair scope. Ask what must be removed to inspect or replace flashing. Identify who repairs cladding, finishes, and the drainage layer afterward. Separate that allowance from the base roofing price.

Likewise, a siding replacement does not give the siding crew permission to assume all existing flashing is usable. Plan an exposed-condition review. If the assembly differs from the bid assumptions, document it and obtain direction before hiding the junction. PNNL's [roof-wall flashing guidance includes retrofit considerations](https://basc.pnnl.gov/resource-guides/step-and-kick-out-flashing-roof-wall-intersections).

Use your [trade scope of work](/guides/trade-scope-of-work/) to state how discoveries become approved changes. Record the condition, proposed correction, price, and effect on the sequence. Keep the instruction with the project documents so the next supervisor can understand it.

## Keep a usable correction record

When you find a defect, name the location and the missing operation. Avoid an instruction such as “fix flashing,” which leaves both crews guessing. Attach the applicable detail and a photo showing the condition. Request a second photo after correction and before covering.

If water appears later, preserve observations before assigning fault. Record weather, visible entry locations, and any recent work nearby. Have the responsible professionals investigate the assembly. A stain below a junction does not tell you which subcontract obligation was breached.

At closeout, retain the scope worksheet, selected details, installation instructions, and exposed-condition photos. Use these documents when investigating a callback. They do not replace a workmanship assessment or a construction attorney's interpretation of the contract.

## Put one junction through the handoff

For a porch roof against an existing wall, mark the junction before requesting final prices. Ask the roofer what wall access is needed. Ask the siding lead who opens and restores that area. Have the builder identify who resolves any concealed damage discovered during removal.

Price the agreed operations and record the sequence. Before siding closes the wall, bring both leads to the marked location. Compare the exposed work with the selected detail and document any correction.

Release that junction only after the responsible site contact accepts the connected layers. This walk-through shows what each crew hands off. The contract still assigns responsibility.

## Where Cercha fits

The Cercha app lets roofing and siding businesses show project photos and portfolios, then contact each other through Messages. Use those conversations to identify comparable experience before assigning the work. Confirm flashing scope and the release for concealment in your project documents.

Published 2026.10.14. Updated 2026.10.14.

[More guides: Trade relationships](</guides/topics/trade-relationships/>)

## Related guides

- [Trade handoffs: who accepts the work before the next crew](</guides/trade-handoffs/>)
- [Writing a trade scope a sub can price](</guides/trade-scope-of-work/>)
- [Inclusions and exclusions in a trade bid](</guides/inclusions-and-exclusions/>)
- [Questions to ask a gutter installer before hiring](</guides/questions-to-ask-gutter-installer/>)

## Build your connections

[Ask about the beta](</beta/>)

## Sources

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1. Pacific Northwest National Laboratory. (2020, September 14). *Step and Kick-Out Flashing at Roof-Wall Intersections*. Building America Solution Center. https://basc.pnnl.gov/resource-guides/step-and-kick-out-flashing-roof-wall-intersections

<a id="source-2"></a>

2. Pacific Northwest National Laboratory. (2022, December 2). *Asphalt Shingle Roofs*. Building America Solution Center. https://basc.pnnl.gov/resource-guides/asphalt-shingle-roofs

<a id="source-3"></a>

3. Pacific Northwest National Laboratory. (2021, September 26). *Gutters and Downspouts*. Building America Solution Center. https://basc.pnnl.gov/resource-guides/gutters-and-downspouts

<a id="source-4"></a>

4. Pacific Northwest National Laboratory. (2020, September 9). *Drainage Plane Behind Exterior Wall Cladding*. Building America Solution Center. https://basc.pnnl.gov/resource-guides/drainage-plane-behind-exterior-wall-cladding

<a id="source-5"></a>

5. Pacific Northwest National Laboratory. (2022, September 9). *Windows and Doors are Fully Flashed*. Building America Solution Center. https://basc.pnnl.gov/resource-guides/windows-and-doors-are-fully-flashed

<a id="source-6"></a>

6. Emily Blackburn. (2025, July 22). *How to install Hardie® Architectural Panels*. James Hardie. https://www.jameshardie.com/blog/for-siding-pros/how-to-install-hardie-architectural-panels/

<a id="source-7"></a>

7. Pacific Northwest National Laboratory. (2025, September 11). *Look for Missing Roof and Wall Flashing*. Building America Solution Center. https://basc.pnnl.gov/diy-guides/look-missing-roof-and-wall-flashing