Shingle Roofing Installation Inspection

Per NBC (National Building Code of Canada) R905.2 and manufacturer specs, the roof deck must be smooth, dry, and structurally sound. Minimum 7/16" OSB or 1/2" plywood sheathing. All gaps >1/4" must be covered or filled. Deck must be fastened per NBC R803 (8d nails, 6" OC at edges, 12" OC field). H-clips required between rafters for spans >24" with 7/16" panels.

1. Verify sheathing type and thickness meet code minimum (7/16" OSB or 1/2" plywood)

2. Check for soft spots, rot, or delamination — walk the deck carefully

3. Confirm proper nailing pattern (6" edges, 12" field)

4. Check gaps between panels — must not exceed 1/8" (H-clips provide proper spacing)

5. Verify H-clips installed where required (check local code requirements)

6. Ensure deck is dry — moisture content below 19% before underlayment

- Rotted sheathing not replaced — new shingles sag or fail at soft spots

- OSB installed upside down (textured side should face up for grip)

- Missing H-clips — sheathing edges curl between rafters

- Deck too wet from rain — traps moisture under underlayment

Per NBC (National Building Code of Canada) R905.2.7, entire roof deck must be covered with approved underlayment. Ice and water shield required in climates where the average January temperature is 25°F (-4°C) or less — extending from eaves to at least 24" past the interior wall line. Synthetic underlayment preferred over felt for most applications. Overlap minimum 4" horizontal, 6" end laps.

1. Verify ice and water shield at eaves — extends minimum 24" past interior wall line

2. Check ice and water shield in valleys (full valley width, minimum 36" wide)

3. Confirm underlayment covers entire deck with proper overlaps (4" horizontal, 6" end)

4. Verify underlayment at penetrations (pipes, vents) — lapped over ice/water shield

5. Check drip edge installed at eaves UNDER underlayment, at rakes OVER underlayment

6. Confirm underlayment is not wrinkled or buckled (telegraphs through shingles)

- No ice and water shield in cold climate — ice dams cause interior leaks

- Ice/water shield not extending far enough past interior wall

- Drip edge over underlayment at eaves (should be under) — water wicks behind

- Underlayment wrinkles — visible lines through shingles

Per NBC (National Building Code of Canada) R905.2.8, flashing required at all roof-to-wall transitions, valleys, chimneys, skylights, and penetrations. Valley flashing: minimum 24" wide metal or woven/cut shingle method. Step flashing: minimum 4"×4" pieces at each course. Counter-flashing must be embedded in mortar joints or reglet. All flashing must be corrosion-resistant (galvanized, aluminum, or copper).

1. Verify step flashing at all roof-to-wall intersections (one piece per shingle course)

2. Check valley method: open metal (24" min), closed-cut, or woven per manufacturer spec

3. Inspect chimney flashing: step flashing + counter-flashing embedded in masonry

4. Verify pipe boot flashing properly installed (base under shingles on uphill side)

5. Check skylight flashing kit — continuous flashing, not just caulk

6. Confirm all flashing overlaps shed water downhill (upper over lower)

7. Verify kick-out flashing at roof-to-wall terminations (prevents water behind siding)

- Missing kick-out flashing — water runs behind siding, causes wall rot

- Step flashing too short — water bypasses during heavy rain

- Pipe boots cracked (rubber degrades in sun) — replace with metal or install new

- Valley flashing too narrow — overflow during heavy rain

Per manufacturer specifications and NBC 905.2, shingles must be installed with proper exposure (typically 5" for standard 3-tab, 5-5/8" for architectural/dimensional). Four to six nails per shingle depending on slope and wind zone. Nail placement per manufacturer's nailing zone (typically 1" above cutout or above adhesive strip). Shingles must be offset minimum 6" between courses.

1. Verify starter strip is installed at eaves and rakes (adhesive strip at drip edge)

2. Check shingle exposure — consistent across the roof (5" or per manufacturer)

3. Verify nail count: 4 nails standard, 6 nails for slopes >60° or high-wind areas

4. Check nail placement — in manufacturer's nailing zone (high nails blow off, low nails crack)

5. Confirm proper offset between courses (minimum 6" for dimensional shingles)

6. Verify shingles are not over-driven (nail heads flush, not cutting through mat) or under-driven

7. Check that shingle adhesive strips are aligned to seal to the course above

- High nailing — nails miss the double-thickness area, shingles blow off in wind

- Overdriven nails — cut through shingle mat, no holding power

- Insufficient offset — creates visible pattern and potential water channel

- Starter strip missing — first course lifts in wind, water enters at eave

Per manufacturer specifications, ridge and hip caps must be installed with proper overlap (exposure typically 5-5/8" for ridge caps). Nails must penetrate through the cap shingle and into the roof deck. Ridge vent, if installed, must be continuous and properly secured. Ridge caps installed opposite to prevailing wind direction.

1. Verify ridge cap shingles are proper type (not cut-down field shingles for dimensional roofs)

2. Check exposure is consistent (match manufacturer spec, typically 5-5/8")

3. Confirm nails are long enough to penetrate cap, ridge vent (if present), and deck

4. Verify ridge vent is continuous along entire ridge (no gaps except at hips)

5. Check that ridge vent baffles are intact (prevent rain/snow infiltration)

6. Confirm last cap shingle is sealed with roofing cement

7. Check hip cap installation from bottom to top with proper overlap

- Ridge vent gaps — rain infiltration at breaks

- Nails too short with ridge vent — cap blows off, vent exposed

- No sealant on last cap — wind lifts and breaks seal

- Wrong cap type for dimensional shingles — aesthetic mismatch and poor seal

Per NBC (National Building Code of Canada) R806, attic spaces must have ventilation ratio of 1:150 (net free area to attic floor area), reduced to 1:300 if balanced between upper and lower vents or if vapor barrier installed. Intake vents (soffit) and exhaust vents (ridge or roof) must be balanced. Do not mix ventilation types (ridge vent + powered fan = short-circuiting).

1. Calculate required net free ventilation area based on attic square footage

2. Verify balanced ventilation: approximately 50% intake (soffit) and 50% exhaust (ridge/roof)

3. Confirm soffit vents are not blocked by insulation (baffles installed at each rafter bay)

4. Check ridge vent is continuous and unobstructed

5. Verify no mixing of ventilation types (ridge vent with turbines or power fans)

6. Check for signs of inadequate ventilation: condensation, mold, ice damming, curled shingles

- Soffit vents blocked by insulation — no intake, ventilation fails completely

- All exhaust, no intake — negative pressure pulls conditioned air through ceiling

- Ridge vent + power vent — fan pulls rain through ridge vent

- Insufficient ventilation — premature shingle failure, voided warranty

Per manufacturer warranty requirements and contractor best practices, all debris must be removed from roof, gutters, and ground. Magnetic nail sweeper must be used on ground around entire perimeter. All leftover materials must be documented (for future repairs). Warranty registration must be completed within required timeframe.

1. Inspect entire roof from ground with binoculars — check for consistent appearance

2. Verify gutters are clean of debris and granules

3. Confirm magnetic sweeper was used around entire building perimeter

4. Check that all pipe boots, vents, and flashing are sealed properly

5. Verify attic interior — check for daylight (indicates missing shingles or flashing gaps)

6. Confirm manufacturer warranty registration is completed

7. Document leftover shingle bundles stored for future repairs (note color and lot number)

- Nails left in yard/driveway — tire punctures, foot injuries

- Gutters full of debris — first rain causes overflow

- Warranty not registered — 25-year warranty reduced to 10-year or voided

- No leftover shingles saved — difficult color match for future repairs