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Safety Cue
Task-specific safety guidance for ordinary work hazards.
Chapter 9
Shingle a Roof Valley
Install one approved open, closed-cut, or woven asphalt-shingle valley, coordinating both adjoining roof planes over the required valley membrane and metal so that water is carried downslope without exposed fasteners or interrupted shingle laps.
Field Cue System
These cues appear at the point of work. They identify safety, code, manufacturer, and measurement issues before they become rework or hazards.
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Critical Safety Cue
Serious injury, fall, or major damage is possible.
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Field Safety Cue
Practical work-area safety: footing, weather, housekeeping, and access.
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Code Alert
Local requirements vary. Verify permit, inspection, and jurisdictional rules.
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Manufacturer Cue
Follow product-specific instructions for materials, fastening schedules, and equipment.
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Measurement Cue
Slope, span, clearance, and reference-point guidance.
Job Overview
This chapter qualifies you to install one complete asphalt-shingle valley, using the approved open, closed-cut, or woven method, on a dedicated valley assembly or on a roof where the adjoining shingle fields have been staged for integrated installation. The finished work product is a clean, continuous valley that carries water downslope without exposed fasteners, reverse laps, or interrupted shingle courses.
You will confirm the approved valley type and its compatibility with both adjoining roof slopes and the selected shingle product, verify that valley membrane and any approved valley metal are already in place, establish the valley centerline and fastener-exclusion zone, coordinate courses from both adjoining roof planes as they cross the valley, cut and finish the valley by the approved method, and inspect the completed valley for water-path integrity before higher courses or ridge work conceal it.
Valleys are the single highest-volume drainage feature on most sloped roofs. A valley built with a narrowed water channel, an exposed fastener, or a broken shingle lap will leak regardless of how well the rest of the roof is installed. This chapter treats the valley as its own controlled assembly, integrated with — not layered on top of — the surrounding shingle field.
Skills You Will Demonstrate
- RF-049 — Identify the approved valley type and confirm its compatibility with both adjoining roof slopes and the selected shingle product.
- RF-050 — Verify and prepare valley underlayment, self-adhered membrane, and any approved valley metal before shingle installation begins.
- RF-051 — Install valley shingles from both adjoining roof planes in coordinated, low-to-high sequence.
- RF-052 — Cut valley lines using the approved method for the selected valley type without cutting underlying materials.
- RF-053 — Maintain an unobstructed water path by keeping fasteners, debris, and sealant out of the valley channel.
- RF-054 — Inspect the completed valley for water-control integrity, including laps, cutlines, fastening exclusion, and drainage continuity.
Where This Skill Fits
This chapter depends directly on the roof-edge, membrane, and underlayment work completed in Chapters 3 through 5, and on the layout and starter-strip work completed in Chapters 6 and 7. The general shingle-field technique from Chapter 8 carries forward here, applied specifically to the valley intersection of two roof planes.
The valley must be built while the surrounding shingle courses are installed, one course at a time on each adjoining plane. It is not a detail that can be added after both fields are shingled. This coordination requirement carries forward into Chapter 10 (sidewall step flashing), Chapter 11 (headwall and apron flashing), and Chapter 12 (penetration flashing), which follow the same course-by-course integration principle, and into the Chapter 20 capstone, which installs any valley present on the approved shed design using this same procedure.
Scope and Intended Use
This chapter covers:
- confirming the approved valley type, membrane, metal, centerline, cutline, fastening-exclusion zone, and lap rules from the roofing-system specification and manufacturer instructions
- confirming that the selected valley method is permitted for both adjoining roof slopes and the chosen shingle product
- inspecting the valley deck, membrane, and metal for support, straightness, damage, debris, and adequate width before shingling begins
- installing shingles from both adjoining roof planes in coordinated, low-to-high sequence for open, closed-cut, or woven valleys
- cutting valley lines using the approved method for the selected valley type
- maintaining exposure, joint offset, and an unobstructed water channel through the valley
- inspecting and documenting the completed valley before it is covered by higher courses or ridge work
This chapter does not authorize the learner to:
- insert a new valley beneath two completed shingle fields; that work requires an approved repair detail and is outside this chapter's scope
- install valley membrane or valley metal; those tasks were completed in Chapters 3 and 4 and are only verified here
- select a valley method not permitted by the roofing-system specification for the roof slopes and shingle product involved
- substitute sealant for required laps, cutline placement, or fastening-exclusion zones
- represent the local water-path observation performed in this chapter as proof of whole-roof or whole-building watertightness
Reference Conventions
Establish these references before shingling begins, and use them consistently across both adjoining roof planes.
| Term | Definition |
|---|---|
| Open valley | A valley in which the approved valley metal remains exposed between trimmed shingle edges on both adjoining planes |
| Closed-cut valley | A valley in which shingles from one adjoining plane run continuously across the valley and are covered by shingles from the second plane, with the upper layer cut along an approved cutline |
| Woven valley | A valley in which shingle courses from both adjoining planes alternate, overlapping across the valley without a cutline, used only where the product and roof geometry permit it |
| Valley centerline | The reference line marking the low point of the valley, used to establish the cutline and the no-fastener zone |
| No-fastener zone | The marked area adjacent to the valley center or metal within which fasteners are prohibited |
| Cutline | The approved line, offset from the centerline by the specified distance, along which the upper shingle layer of a closed-cut valley is trimmed |
| Clipped corner | The upper corner of a valley-crossing shingle, trimmed at an angle where required to direct water into the valley |
Valley Work Record
Before beginning shingle installation, record the controlling references directly on the project record:
Project / address: ______ Approved valley type: ______ Roof planes joined: ______ / ______
Valley membrane and metal reference (Chapters 3–4 record): ______ No-fastener zone width: ______
Date started: ____________ Installer name: ____________
Prerequisites
- Approved valley type, roof slopes, shingle limitations, membrane, metal, centerline, cutline, fastening-exclusion zones, lap rules, and manufacturer details confirmed from the roofing-system specification
- Confirmation that the selected valley method is permitted for both adjoining roof slopes and the chosen shingle product
- Self-adhered valley membrane and any approved valley metal installed under Chapter 4 in low-to-high shingle-lap order
- Underlayment, roof-edge metal, layout lines, and starter strips complete on both adjoining roof planes per Chapters 3, 5, 6, and 7
- Roof-access and fall-protection systems from Chapter 2 accepted for the current work zone
- Weather conditions suitable for shingle installation and cutting operations
Common Field Fundamentals
A valley is not a repair to a finished roof plane; it is a coordinated intersection of two planes built together, course by course, from the lower end toward the ridge. The membrane and any metal installed in Chapters 3 and 4 already establish the water path beneath the shingles. This chapter's job is to keep that path clear as the shingle field crosses it — never to insert a valley after the fact and never to interrupt the shingle-lap order that carries water from upper courses onto lower ones.
Valley centerlineReference for cutline and no-fastener zone; verified against membrane and metal already in place
No-fastener zoneMarked width adjacent to the valley center; no fasteners permitted inside it
Closed-cut sequenceFirst plane runs across the valley; second plane laps over it and is cut to the approved cutline
Open valleyBoth planes trimmed to the approved opening, symmetrical cut edges, no fasteners in the metal
Woven valleyAlternating courses from both planes; used only where product and geometry permit
Clipped cornersUpper corners trimmed where required to direct water into the channel
Water channel housekeepingCutoffs, granules, nails, and sealant removed from the channel before covering
Verification methodApproved visual or controlled water-path observation, not a whole-roof leak test
Coordinating Both Roof Planes
Shingle both adjoining roof planes together as they approach the valley, matching course exposure and joint offset from each plane's own layout lines established in Chapter 6. Do not complete one entire roof plane and then start the second; the valley method you are using controls which plane crosses first and how the second plane laps over or weaves with it.
RF-049 – RF-054
Shingle Installation / Water-Path Control
Roof Valley Shingle Installation
A. Finished-Work Specification
Deliverable: one continuous open, closed-cut, or woven asphalt-shingle valley, built over the approved membrane and metal, with coordinated course exposure and joint offset from both adjoining roof planes, an unobstructed no-fastener zone, a straight and symmetrical cutline or opening where applicable, and a completed inspection record with photographs.
B. Governing Documents
| Document | Confirmed Current | Notes |
|---|---|---|
| Roofing-system specification (valley type) | ||
| Shingle manufacturer instructions | ||
| Valley membrane and metal manufacturer instructions | ||
| Chapter 4 membrane installation record | ||
| Chapter 6 layout record for both adjoining planes |
C. Acceptance Standards
| Check | Standard |
|---|---|
| Valley method | Matches the type authorized by the roofing-system specification for both adjoining slopes and the selected shingle product |
| Membrane and metal | Confirmed installed in low-to-high shingle-lap order before valley shingling begins |
| No-fastener zone | Marked at the specified width; free of fasteners on inspection |
| Cutline (closed-cut) or opening (open valley) | Straight, symmetrical, offset from centerline by the specified distance |
| Course coordination | Exposure and joint offset from both adjoining planes maintained through the valley |
| Water channel | Free of cutoffs, loose granules, nails, and excess sealant |
| Verification | Approved local visual or controlled water-path observation completed and documented, not represented as a whole-roof test |
D. Required Project Sequence
- Review the approved valley type, roof slopes, shingle limitations, membrane, metal, centerline, cutline, fastening exclusion zones, lap rules, and manufacturer details. Confirm every value against the roofing-system specification and record it on the Valley Work Record before proceeding.
- Confirm that the selected valley method is permitted for both adjoining roof slopes and the chosen shingle product. If the specification does not clearly authorize the method for both planes, stop and obtain confirmation before continuing.
- Do not attempt to insert a new valley beneath two completed shingle fields unless an approved repair detail specifically permits it. Verify that both adjoining fields have been staged, not completed, for integrated installation before beginning this chapter's work.
- Inspect the valley deck for support, straightness, damage, debris, and adequate width. Confirm findings against the readiness record from Chapter 1 and correct only items authorized under that chapter's scope.
- Verify that required self-adhered valley membrane and any approved valley metal are installed in low-to-high shingle-lap order. Confirm this against the Chapter 4 membrane record before placing any shingle in the valley.
- Establish the valley centerline and approved cutline or shingle-control lines. Snap the centerline from the membrane or metal reference and mark the cutline or control lines at the specified offset.
- Identify and mark the no-fastener zone adjacent to the valley center or metal. Mark the zone at the specified width on both adjoining planes before installing any valley-adjacent shingle.
- Begin shingle installation at the lower valley end and coordinate courses from both adjoining roof planes. Work upslope, matching each plane's own exposure and joint-offset references from Chapter 6.
- For a closed-cut valley, install the first roof plane across the valley by the required distance and fasten outside the exclusion zone. Extend the specified plane's shingles across the valley centerline and secure only fasteners located outside the marked no-fastener zone.
- Install the second roof-plane shingles over the first and mark the approved cutline. Lap the second plane's shingles over the first plane's valley-crossing courses and mark the cutline at the specified offset before cutting.
- Cut the upper shingle layer without cutting the underlying shingles, membrane, or valley metal. Use the hooked or straight utility-knife blade specified for this cut and control blade depth to the shingle thickness only.
- Clip upper corners where required to direct water into the valley. Trim the upper corner of each valley-crossing shingle at the angle specified by the manufacturer instructions where the detail requires it.
- Apply manufacturer-approved sealant only at specified concealed locations. Do not apply sealant to the cutline, exposed shingle edges, or any location not explicitly identified for sealant use.
- For an open valley, trim shingles to the approved opening and keep cut edges straight and symmetrical. Cut both adjoining planes to the same offset from centerline and check the opening width at intervals along the valley length.
- For a woven valley, weave courses only when the product and roof geometry permit it and keep joints out of the valley center. Alternate courses from each plane across the valley according to the manufacturer's weave sequence and confirm no shingle joint lands within the marked centerline zone.
- Maintain course exposure and joint offsets as shingles cross or approach the valley. Check each course against the horizontal and vertical control lines established in Chapter 6 before fastening.
- Remove cutoffs, loose granules, nails, and sealant from the water channel. Clear the channel after each cutting or fastening operation, not only at the end of the chapter.
- Inspect the full valley for reverse laps, exposed fasteners, punctures, uneven cutlines, trapped debris, narrow water paths, and unsupported shingle edges. Walk the full valley length from an approved position and record each finding.
- Correct defects before installing higher courses or ridge work. Complete every correction identified in Step 18 and recheck the affected section before shingling continues above the valley.
- Conduct the approved visual or controlled water-path observation without overstating it as a whole-roof leak test. Perform only the observation method authorized by the roofing-system specification and record its limits in the project record.
- Photograph and document valley type, membrane, metal, fastening exclusion, cutline, and completed condition. Attach photographs to the project record before higher courses conceal the valley.
Common Valley Installation Checks
Apply the same checks to every valley, regardless of the roof's overall size or configuration.
- Method-authorization check: confirm the selected valley method is permitted for both adjoining slopes and the shingle product before the first valley-crossing shingle is installed.
- Membrane and metal check: confirm Chapter 4 membrane and any valley metal are complete and accepted before shingling begins.
- No-fastener zone check: confirm the marked zone width matches the specification and remains free of fasteners on inspection.
- Cutline or opening check: confirm the cutline or opening is straight, symmetrical, and at the specified offset along the full valley length.
- Coordination check: confirm exposure and joint offset from both adjoining planes are maintained through the valley.
- Housekeeping check: confirm the water channel is free of cutoffs, granules, nails, and sealant before the valley is covered by higher courses.
Complete the Valley Inspection Record in the Inspection Checklist section below before installing higher courses or beginning ridge work.
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Failure Points and Troubleshooting
Cleanup
This chapter ends with a clean, inspected valley and a documented record, not exposed cutoffs or unmarked corrections.
- Remove all shingle cutoffs, loose granules, nails, and packaging from the valley channel and surrounding roof surface
- Dispose of removed material using a method that does not discharge it from the roof edge or the ground below
- Wipe excess sealant from any exposed surface adjacent to approved concealed sealant locations
- Store unused shingles, matched by product and lot, for use in the adjoining field courses
- Compile the Valley Work Record, photographs, and inspection findings into the project record before installing higher courses or beginning ridge work
Field Terms
- Open Valley
- A valley in which approved valley metal remains exposed between trimmed shingle edges on both adjoining planes.
- Closed-Cut Valley
- A valley in which one plane's shingles run continuously across the valley and are covered by the second plane's shingles, cut along an approved cutline.
- Woven Valley
- A valley in which courses from both adjoining planes alternate and overlap across the valley without a cutline.
- Valley Centerline
- The reference line marking the low point of the valley, used to establish the cutline and no-fastener zone.
- No-Fastener Zone
- The marked area adjacent to the valley center or metal within which fasteners are prohibited.
- Cutline
- The approved line, offset from the centerline, along which the upper shingle layer of a closed-cut valley is trimmed.
- Clipped Corner
- The upper corner of a valley-crossing shingle, trimmed at an angle where required to direct water into the valley.
- Water Channel
- The clear path within the valley through which runoff drains downslope, kept free of fasteners, debris, and excess sealant.
Skill Check
- What must be confirmed about a valley method before it is used, and where is that confirmation found?
- Why is inserting a new valley beneath two completed shingle fields outside this chapter's authorized scope?
- What is the purpose of the no-fastener zone, and how is its width determined?
- Describe the coordinated sequence for installing a closed-cut valley, including which plane crosses first and how the cutline is established.
- Why must valley-crossing courses be checked against each plane's own Chapter 6 layout lines rather than against each other?
- Where is sealant permitted in a valley assembly, and where is it prohibited?
- What must be removed from the water channel before higher courses are installed over the valley?
- What is the difference between the local water-path observation performed in this chapter and a whole-building leak test?
- Why must defects found during the water-path observation be corrected at their source rather than sealed over?
- Why must the completed valley be photographed and documented before it is covered by higher courses or ridge work?
Competency Rubric
| Competency | Independent Pass Standard | Not Demonstrated | With Assistance | Independently |
|---|---|---|---|---|
| RF-049 | Correctly identifies the approved valley type and confirms its compatibility with both adjoining roof slopes and the selected shingle product before installation begins | |||
| RF-050 | Verifies valley membrane and any approved valley metal are complete and correctly sequenced before installing valley shingles | |||
| RF-051 | Installs valley shingles from both adjoining roof planes in coordinated, low-to-high sequence with matched exposure and joint offset | |||
| RF-052 | Cuts valley lines using the approved method for the selected valley type without cutting underlying shingles, membrane, or metal | |||
| RF-053 | Maintains an unobstructed water path, keeping fasteners, debris, and sealant out of the valley channel | |||
| RF-054 | Inspects and documents the completed valley for laps, cutline accuracy, fastening exclusion, and drainage continuity before it is covered |
Mark one column per competency. Only Demonstrated Independently awards the competency; Demonstrated with Assistance authorizes additional supervised practice but does not complete the requirement.
Inspection Checklist — Valley Inspection Record
| Item | Condition Found | Correction Required | Corrected (Y/N) | Reinspection Result |
|---|---|---|---|---|
| Valley method authorization | ||||
| Membrane and metal condition | ||||
| No-fastener zone | ||||
| Cutline / opening straightness and offset | ||||
| Course exposure coordination | ||||
| Clipped corners (where required) | ||||
| Sealant locations | ||||
| Water channel housekeeping | ||||
| Local water-path observation |
Valley completion decision: ______ (Proceed to Higher Courses / Corrections Required / Stop-Work) Date: ____________ Installer name: ____________
Performance Check
With the valley complete, review the Valley Inspection Record against the Acceptance Standards table and confirm the valley method matches the approved specification for both adjoining slopes, membrane and metal were verified before shingling, the no-fastener zone is clear on inspection, the cutline or opening is straight and symmetrical at the specified offset, course exposure and joint offset are coordinated between both planes, the water channel is free of debris and excess sealant, and the approved local water-path observation is complete and documented with its limits stated. Correct every outstanding item and recheck the affected section before installing higher courses or beginning ridge work.
Chapter Closeout
You have completed the roof-valley chapter in the shingle-installation sequence: integrating two adjoining roof planes into one continuous, water-controlled valley. This chapter required you to identify the approved valley type and confirm its compatibility with both roof slopes and the shingle product (RF-049), verify valley membrane and metal preparation (RF-050), install valley shingles in coordinated sequence (RF-051), cut valley lines using the approved method (RF-052), maintain the water path (RF-053), and inspect the completed valley for water-control integrity (RF-054).
You now have a documented, inspected valley that the surrounding shingle field and every later chapter depend on. That record carries forward into the remaining flashing chapters, which use the same course-by-course integration principle at sidewalls, headwalls, and penetrations, and into the Chapter 20 capstone, which applies this exact valley procedure to the approved shed design where a valley condition is present.
Store the completed Valley Work Record, photographs, and inspection findings with the project record before installing higher courses or beginning ridge work.