Why Nails, Screws, and Sealants Matter

A typical roof uses 5,000-10,000 fasteners. Each one is a potential failure point. Use the wrong nail, install it incorrectly, or skip a fastener to save time, and you've created a weak point that wind will exploit.

This guide covers the fasteners and sealants used in roofing, why specific types matter, and how proper fastening techniques prevent failures.

Roofing Nails

Standard Roofing Nails (Asphalt Shingles)

Specifications:

• Length: 1-1/4 inches (minimum for new construction)
• Shank: Smooth or ring-shank
• Head: 3/8 inch diameter minimum
• Material: Galvanized steel or stainless steel

Ring-Shank vs. Smooth-Shank:

Ring-Shank (Our Standard in High-Wind Areas):

• Rings along shank provide superior holding power
• 40% more wind uplift resistance than smooth-shank
• Required in Hope and exposed Chilliwack areas
• Cost: $5-10 more per box (negligible on full roof)

Smooth-Shank:

• Adequate for low-wind areas
• Easier to drive (faster installation)
• Lower cost

Our Policy: We use ring-shank nails in Hope, exposed Chilliwack slopes, and any property with documented high-wind history. The $50-100 cost difference is worth the peace of mind.

The 4-Nail vs. 6-Nail Debate:

BC Building Code: 4 nails per shingle in most zones

Our Standard in High-Wind Areas: 6 nails per shingle

Why:

• Each nail adds approximately 10% wind uplift resistance
• 6 nails = 50% more holding power than code minimum
• Cost difference: $50-100 per roof (about 2,000 extra nails)
• We've seen 4-nail installations fail in Hope windstorms

Metal Roofing Screws

Exposed-Fastener Panels:

• Type: Self-drilling screws with neoprene washers
• Length: 1-1/2 to 2 inches (depends on panel profile and deck thickness)
• Head: Painted to match panel color
• Washer: EPDM rubber (UV-resistant)

Critical Detail: Screws must be driven to proper torque — not too tight (crushes washer), not too loose (allows water entry). This is where inexperienced installers fail.

Standing Seam Clips:

• Concealed fastening system
• Clips attach to deck, panels snap onto clips
• Allows thermal expansion/contraction
• No exposed fasteners to leak or corrode

Sealants & Adhesives

1. Roofing Cement (Asphalt-Based)

What It Is:

Thick, tar-like sealant used for flashing, repairs, and sealing penetrations.

Types:

Plastic Cement:

• General-purpose sealant
• Used for flashing, pipe boots, small repairs
• Not paintable

Lap Cement:

• Thinner consistency
• Used for bonding overlapping materials
• Not for exposed applications

Flashing Cement:

• Fiber-reinforced
• Extra adhesion for vertical surfaces
• Used for chimney flashing, sidewalls

Our Use: We use roofing cement sparingly and only where appropriate (under flashing, around penetrations). We don't use it as a substitute for proper flashing.

2. Polyurethane Sealant

What It Is:

Flexible, paintable sealant that adheres to most roofing materials.

Advantages:

• Excellent adhesion to metal, wood, masonry
• Flexible (accommodates thermal expansion)
• Paintable
• UV-resistant
• 20-30 year lifespan

Our Use: Metal roofing seams, flashing terminations, skylight perimeters.

3. Silicone Sealant

Advantages:

• Superior UV resistance
• Extreme temperature tolerance (-40°C to +150°C)
• Excellent adhesion to glass and metal
• 30+ year lifespan

Disadvantages:

• Not paintable
• Expensive
• Difficult to remove if replacement needed

Our Use: Skylight glazing, metal-to-metal seams on premium projects.

4. Butyl Tape

What It Is:

Sticky, rubber-like tape used for sealing metal roofing seams and flashing.

Advantages:

• Excellent adhesion
• Conforms to irregular surfaces
• No curing time required
• Works in cold temperatures

Our Use: Standing seam metal roofing seams, flashing laps, ridge cap sealing.

Common Fastening Mistakes

1. Under-Nailing

Using fewer nails than required to save time or materials. This is the #1 cause of shingle blow-offs.

Code Requirement: 4 nails per shingle (6 in high-wind zones)

What We See: Contractors using 3 nails or even 2 nails to speed installation

Result: Shingles blow off in first major windstorm

2. Over-Driving Nails

Driving nails too deep, cutting through shingle and creating a hole.

Proper Depth: Nail head flush with shingle surface, not embedded

Result of Over-Driving: Water penetrates through nail hole, causing leaks and deck rot

3. Under-Driving Nails

Not driving nails flush, leaving head protruding.

Result: Shingle above doesn't seal properly, wind can lift shingle

4. Wrong Fastener Placement

Nails placed too high or too low on shingle.

Proper Placement: Just below adhesive strip, above slots (for 3-tab) or in designated nail zone (for architectural)

Result of Improper Placement: Reduced wind resistance, visible nail heads, potential leaks

5. Using Caulk as a Substitute for Proper Flashing

This is the worst mistake we see. Contractors use caulk instead of installing proper step flashing, counter flashing, or crickets.

Why This Fails:

• Caulk degrades in 3-5 years (UV exposure, thermal cycling)
• Caulk doesn't direct water — it just blocks it temporarily
• When caulk fails, water pours into wall cavities

Our Policy: We never use caulk as a substitute for proper flashing. Ever.

The Bottom Line

Fasteners and sealants are small, cheap components. But they hold your entire roof together. Using the right fastener, installing it correctly, and sealing it properly is the difference between a roof that lasts 30 years and one that fails in 10.

At RJ Roofing Bros, we don't cut corners on fasteners. Ring-shank nails in high-wind areas. Six nails per shingle where needed. Proper sealants in the right applications. No caulk substitutes.

Questions about installation standards? Call (604) 997-1292 and we'll explain our process.