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newSchoolWorks.com › VoTechWorks › Building & Construction › Carpentry › Roofing: Systems, Materials, and Installation › Lesson 12
BLD-CARP03-04 · Lesson 12 · 16 clock hours · field

Integrated Roofing Lab: Full Roof System on Practice Structure

Objective. Students will complete a full residential roof assembly—sheathing through ridge vent—on the program's practice structure, meeting all dimensional and quality standards established in prior lessons.

Integrated Roofing Lab: Full Roof System on Practice Structure

This lab brings together every skill you have practiced in the preceding lessons. You and your crew will install a complete residential roof system—from sheathing through ridge vent—on the program's practice structure. The goal is not speed; it is a quality assembly that sheds water correctly and would pass a real inspection on a real house.

Why a Sequenced, Crew-Based Approach Matters

Roofing is almost never a solo trade. On a job site, crews divide labor by task so work flows without one phase blocking the next. Planning before you climb prevents wasted trips and unnecessary exposure on the roof. Before anyone sets foot above the eave, the crew must:

Fall Protection: Non-Negotiable Before Ascending

Fall protection is the most critical safety requirement in this lab. OSHA's construction standards require fall protection for roofing work at or above six feet. On this structure, every worker on the roof slope wears a full personal fall-arrest system: harness, lanyard or self-retracting lifeline, and anchored to a certified roof anchor. Inspect your harness for fraying, broken buckles, or damaged hardware before each use. A damaged harness must be removed from service immediately. The crew leader reads the fall-protection checklist aloud before anyone ascends. If a safety violation is observed during the lab—loose lanyard, unclipped harness, improper ladder placement—work stops, the violation is corrected, and a mandatory safety re-demonstration is required before your score is recorded.

Additional PPE for this lab: hard hat, safety glasses, work gloves, and slip-resistant footwear. When operating the pneumatic nailer, keep fingers clear of the nose of the tool and never bypass the safety tip. Before adjusting the nailer or clearing a jam, disconnect it from the air supply.

Installation Sequence and Quality Standards

Sheathing. Panels run perpendicular to rafters, long edge horizontal. Stagger end joints by at least one rafter bay. Leave a 1/8-inch expansion gap at panel edges. Fasten per the nailer schedule—typically 6d or 8d nails at 6 inches on panel edges and 12 inches in the field.

Drip edge. Install at the eave first, then the rake after underlayment is down. Lap end joints at least 2 inches, high side over low. Nail at roughly 12-inch intervals. Drip edge directs water into the gutter and away from the fascia.

Underlayment. Roll out parallel to the eave with the required head-lap (check the product specification—commonly 2 inches for 15-lb felt, more for synthetic). Lap each course over the one below, never under. Fasten with cap nails or staples as the product requires. Keep the surface flat; wrinkles telegraph through shingles and can trap water.

Valley flashing. Open valleys use metal flashing centered in the valley. Closed-cut or woven valleys use shingles. Follow the detail specified for this structure. Metal flashing laps a minimum of 6 inches at horizontal joints, high over low. Seal exposed nail heads in the valley with roofing cement.

Field shingles. Snap chalk lines for each course. The standard starter course overhangs the eave drip edge by 1/4 to 3/8 inch. Maintain consistent exposure (commonly 5 inches for three-tab shingles, varying for architectural). Offset vertical joints by at least 6 inches course to course. Nail placement follows the manufacturer's nailing zone—typically four nails per shingle, just above the adhesive strip, not on it. Misplaced fasteners void warranties and allow shingles to lift.

Step flashing at a wall. Each piece of step flashing integrates with one course of shingles: shingle over step flashing, next step flashing over shingle, and so on up the wall. Minimum 4-inch vertical leg against the wall, minimum 4-inch horizontal leg under the shingle. Never caulk step flashing as a substitute for correct overlap.

Pipe boot. Slide the boot flange under the upper shingles and over the lower shingles. Seal the flange perimeter with roofing cement; do not rely on caulk alone at the pipe collar.

Ridge vent and cap shingles. Cut the ridge slot to the manufacturer's specified width—do not over-cut. Install the ridge vent per manufacturer instructions, nailing through the vent into the ridge board. Cap shingles lap a minimum of 5 inches and are nailed so each nail is covered by the next cap shingle.

Peer Inspection and Debrief

At project completion, your crew swaps punch-lists with another crew and conducts a structured inspection: alignment within ±1/4 inch, correct lap dimensions at every layer, fastener pattern in the manufacturer's nailing zone, flashing laps that shed water (high over low throughout), and ridge vent slot width. Write down what you find—both what is correct and what needs correction. In the debrief, present findings professionally; you are building the habit of quality control that every journeyman carpenter is expected to practice.

Key terms9

Personal fall-arrest system (PFAS)A combination of harness, connecting lanyard or self-retracting lifeline, and a certified anchor point that stops a worker's fall and limits the force on the body; required by OSHA for roofing work at or above six feet.
Drip edgeA metal flashing installed along eaves and rakes that directs water off the roof deck and away from the fascia board into the gutter; installed at eaves before underlayment and at rakes after underlayment.
Head-lapThe vertical distance by which one course of underlayment or shingles overlaps the course two layers below it; a minimum head-lap is specified by the product manufacturer to prevent water infiltration.
Step flashingIndividual L-shaped metal pieces integrated course-by-course with shingles where a roof slope meets a vertical wall; each piece diverts water outward over the shingle below it.
Valley flashingMetal or shingle material installed in the concave intersection of two roof slopes to channel water from both slopes to the eave without leaking through the joint.
Pipe boot (pipe flashing)A pre-formed rubber or metal flashing collar that seals around a pipe penetrating the roof; the lower flange laps over shingles below, and upper shingles lap over the upper flange.
Ridge ventA continuous ventilation device installed along the roof ridge over a slot cut in the sheathing; allows hot, moist air to escape the attic and is covered by cap shingles.
Shingle exposureThe portion of each shingle course left visible and unprotected by the course above it; controlled by chalk lines and directly affects weather resistance and appearance.
Punch-listA structured written checklist used to identify incomplete or deficient work on a project; in roofing, it covers alignment, lap dimensions, fastener placement, flashing laps, and ventilation.

Worked examples4

1. The practice structure ridge is 16 feet long. You are installing cap shingles with a 5-inch exposure. How many cap shingles do you need to cover the ridge, and how many full rows of 3-tab cap pieces (each piece 12 inches wide) fit in 16 feet?
  1. Step 1: Convert ridge length to inches. 16 ft × 12 in/ft = 192 inches.
  2. Step 2: Determine how many cap shingles are needed. With a 5-inch exposure, each shingle advances 5 inches along the ridge. Number of shingles = 192 ÷ 5 = 38.4, so round up to 39 cap shingles.
  3. Step 3: Verify the last shingle. 38 shingles × 5 inches = 190 inches covered; the 39th shingle covers the remaining 2 inches at the ridge end and is trimmed or lapped as needed.
Answer: You need 39 cap shingles to cover a 16-foot ridge at 5-inch exposure.
2. Your underlayment roll covers the first course. The course must start with a 4-inch overhang at the eave and each subsequent course laps the previous by 2 inches (head-lap). The roof slope is 9 feet tall measured along the slope (rake length). How many underlayment courses are needed?
  1. Step 1: Convert rake length to inches. 9 ft × 12 in/ft = 108 inches.
  2. Step 2: Subtract the starter overhang from the total to find length that courses must cover above the first course position. The first course edge is at the eave, covering 36 inches of felt width. Effective advance per course after the first = 36 in – 2 in head-lap = 34 inches.
  3. Step 3: Remaining height after the first course = 108 in – 36 in = 72 inches.
  4. Step 4: Additional courses needed = 72 ÷ 34 = 2.12, round up to 3 additional courses.
  5. Step 5: Total courses = 1 (first) + 3 = 4 courses.
Answer: 4 courses of underlayment are needed to cover a 9-foot rake with a 2-inch head-lap.
3. You are laying three-tab shingles with a 5-inch exposure. The rake-to-rake width of the roof section is 24 feet. Shingles come in bundles covering 33.3 square feet per bundle, three bundles per square (100 sq ft). The roof section is one slope measuring 24 feet wide by 18 feet long (rake). How many bundles do you need for that slope, adding 10% for waste?
  1. Step 1: Calculate gross area. 24 ft × 18 ft = 432 square feet.
  2. Step 2: Add 10% waste. 432 × 1.10 = 475.2 square feet.
  3. Step 3: Divide by coverage per bundle. 475.2 ÷ 33.3 = 14.27 bundles.
  4. Step 4: Round up to the nearest whole bundle. You need 15 bundles.
Answer: Order 15 bundles of shingles for that slope.
4. The manufacturer requires step flashing pieces to have a minimum 4-inch vertical leg and a minimum 4-inch horizontal leg. You are cutting step flashing from a roll of metal that is 10 inches wide. What length must you cut each piece so it equals the shingle exposure of 5 inches plus an additional 2 inches of overlap onto the shingle below?
  1. Step 1: The horizontal leg of step flashing must cover the shingle exposure (5 inches) plus the overlap onto the shingle below (2 inches). Required length = 5 + 2 = 7 inches.
  2. Step 2: Verify the minimum horizontal leg. 7 inches exceeds the 4-inch minimum—acceptable.
  3. Step 3: The 10-inch wide stock is bent: 4 inches becomes the vertical leg, leaving 10 – 4 = 6 inches for the horizontal leg. 6 inches is less than the required 7 inches.
  4. Step 4: Adjust. Use 11-inch wide stock: 4 in vertical + 7 in horizontal = 11 inches total width. Cut each piece to a length that matches the course spacing—here each piece is 7 inches long (the dimension running up the slope).
Answer: Each step flashing piece should be cut from 11-inch wide stock and trimmed to 7 inches in the up-slope direction to achieve the required legs and overlap.

The math in this lesson1

Learners count ridge caps at 5 in exposure, underlayment courses with laps, and shingle bundles at 33.3 sq ft each.
N-Q.1
Brush up in the math halls at newSchoolWorks.com:
In class: Working in a crew of three to four, plan the day's sequence of tasks, assign roles (sheathing team, underlayment team, shingle team), and review fall-protection setup as a group before ascending the roof. · Execute the complete installation sequence—sheathing, drip edge, underlayment, valley flashing, field shingles, step flashing at a wall, pipe boot, and ridge vent/cap shingles—with instructor coaching at each transition point. · Conduct a peer quality inspection at project completion using a structured punch-list checklist covering alignment, fastening, lap dimensions, flashing laps, and ventilation, then present findings in a brief oral debrief.
Materials: All materials from Lessons 5–9 (sheathing, drip edge, underlayment, shingles, flashing, ridge vent, fasteners), pneumatic nailer, compressor, circular saw, chalk line, tape measure, speed square, utility knife, full PPE including fall-arrest system; punch-list checklist; field notebooks
Check: Instructor scores the completed roof using the program's 20-point roofing quality rubric (alignment ±1/4 inch, lap dimensions, fastener pattern, flashing water-shedding, ventilation slot width); minimum passing score is 16/20; any safety violation during the lab results in a mandatory safety re-demonstration before the score is recorded.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

OSHA 10 – Fall Protection
1. Before any crew member ascends the roof on lab day, what must the group do as a team?
NCCER Carpentry – Roofing Systems
2. At which eave location is drip edge installed relative to the underlayment?
OSHA 10 – Tool Safety / Lockout-Tagout
3. A worker's pneumatic nailer jams on the roof. What is the correct first action?
NCCER Carpentry – Roofing Quality Control
4. The roofing quality rubric requires shingle course alignment within ±1/4 inch. You snap a chalk line and your first three courses are straight, but the fourth course drifts 1/2 inch off the line at mid-span. What is the best corrective action before laying more shingles?
NCCER Carpentry – Roofing Systems
5. Which statement correctly describes the water-shedding principle that governs every flashing lap on a roof?
NCCER Carpentry – Ventilation and Roofing Quality
6. During the peer punch-list inspection, you find that the ridge vent slot is cut 1 inch wider than the manufacturer specifies. Why is this a deficiency worth noting?
NCCER Carpentry – Flashing Installation
7. Step flashing is installed where a roof slope meets a vertical wall. Which installation method is correct?
OSHA 10 – Worksite Safety Accountability
8. The program rubric requires a minimum passing score of 16 out of 20 points, and any safety violation triggers a mandatory safety re-demonstration before the score is recorded. A crew finishes with a quality score of 17/20 but the instructor observed one worker with an unclipped lanyard for several minutes. What happens to that crew's score?
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