Do I Need Closure Strips for Metal Roofing

Do You Need Closure Strips for Metal Roofing?

When installing a metal roof, one common question is whether closure strips are necessary. Closure strips play a significant role in providing a weatherproof seal, preventing pest entry, and improving the overall integrity of metal roofing systems. This article explores the purpose, types, and benefits of closure strips in metal roofing to help homeowners and contractors make informed decisions.

What Are Closure Strips in Metal Roofing?

Closure strips are thin foam or rubber materials designed to fill gaps between metal roofing panels and the structural supports beneath them. These strips conform to the corrugations or shape of metal panels, creating a tight seal along edges, ridges, and eaves. They typically come pre-cut to match the profile of metal roofing panels and can be attached easily during installation.

Closure strips are essential accessories that complement metal roofing systems by preventing water infiltration, reducing air leakage, and blocking pests like birds and insects from entering the attic or roof cavity through small openings.

Types of Closure Strips for Metal Roofs

Different closure strip materials offer various benefits depending on the roofing system and environmental conditions.

• Open-Cell Foam Closure Strips: These allow some airflow while sealing gaps. They are usually less effective against pests and water.
• Closed-Cell Foam Closure Strips: Dense and waterproof, these provide excellent sealing against moisture and wind. They are common in most installations.
• Rubber Closure Strips: Durable and resilient, rubber strips provide a tight seal and resist deterioration from UV and weather exposure.
• Vinyl Closure Strips: Flexible and weather-resistant, vinyl strips also offer a good seal but may have a shorter lifespan compared to rubber.

Choosing the appropriate closure strip depends on the metal panel profile, local climate, and budget.

Why Closure Strips Are Important for Metal Roofing

Weatherproofing and Leak Prevention

Metal roofing panels usually have corrugated or ribbed profiles, leaving small spaces when fastened. Without closure strips, rainwater and wind-driven moisture can seep into these gaps, causing leaks and water damage to the roof deck and insulation below. Closure strips seal these gaps effectively, enhancing the weatherproof nature of a metal roof.

Pest Blockage

Gaps beneath metal roofing can become an entry point for insects, birds, and rodents. These pests can create nests, damage insulation, and compromise the roofing structure. Closure strips act as a physical barrier that prevents the intrusion of unwanted wildlife and insects, maintaining a cleaner and safer roof cavity.

Improved Energy Efficiency

Metal roofs can experience temperature fluctuations due to air leakage. Closure strips reduce these leaks by sealing air gaps, which helps maintain indoor temperatures and reduce energy costs associated with heating and cooling.

Noise Reduction

Wind and rain striking a metal roof can cause significant noise. Closure strips help dampen these sounds by absorbing vibrations and blocking airflow, leading to a quieter indoor environment.

Extending Roof Service Life

Moisture infiltration and pest damage can shorten the lifespan of metal roofing components. Closure strips protect the roof structure from these threats, contributing to increased durability and longevity of the roofing system.

When Are Closure Strips Necessary for Metal Roofing?

While many metal roofing manufacturers recommend using closure strips, some conditions make their use particularly critical:

• Exposed edge areas: Eaves, ridges, and rakes where panels terminate are especially vulnerable to moisture and pests.
• High wind or heavy rainfall regions: Areas with severe weather benefit significantly from enhanced sealing.
• Pest-prone areas: Rural or wooded locations where insects and animals are prevalent.
• Metal panels with large corrugations or rib profiles: Larger gaps require effective sealing to avoid moisture and pest entry.

In some situations, such as low-slope roofing or specialized waterproof membrane installations, closure strips might be optional or replaced by alternative flashing and sealing methods.

How to Install Closure Strips on a Metal Roof

Proper installation is key to the effectiveness of closure strips. Here is a step-by-step overview:

1. Measure the metal panel profile: Select closure strips matching the panel’s corrugation shape.
2. Clean the roof deck surface: Remove dirt, debris, and moisture to ensure a good seal.
3. Cut closure strips to length: Use utility scissors or a knife to match panel dimensions.
4. Place strips beneath metal panels: Align strips carefully to fit into every ridge or valley.
5. Secure metal panels: Attach panels over the closure strips using proper fasteners.
6. Check seals: After installation, inspect for gaps or displaced strips and adjust accordingly.

Proper sealing with closure strips is a simple yet critical step to ensure a weather-tight and pest-resistant metal roof installation.

Do Closure Strips Increase Metal Roofing Costs?

Closure strips are relatively inexpensive, adding only a small fraction to the total roofing cost. The advantages they provide in protecting against water damage, pest issues, and energy loss far outweigh the modest expense. Considering the long-term benefits, skipping closure strips can result in costly repairs and reduced roof lifespan.

Typically, closure strips cost between $0.25 and $0.75 per linear foot depending on material and profile. Installation time is minimal, which helps keep labor costs low.

Alternatives to Closure Strips and When They Apply

Some metal roofing systems or building codes allow alternatives, such as:

• Metal foam tape or sealants: Acting as a flexible filling for gaps in place of foam strips.
• Special flashings and trims: Designed to cover gaps along edges and ridges.
• Spray foam insulation: Used in some retrofit or residential projects to seal gaps from beneath.

However, these alternatives must provide equal or better protection against weather and pests and be approved by roofing product manufacturers and local codes.

Choosing the Right Closure Strips for Your Metal Roof

To select closure strips compatible with your roof:

• Match the profile: Identify the contour of your metal roofing panels (e.g., 1-inch corrugation, 2-inch ribs) and buy strips designed for that profile.
• Material durability: For harsh climates, choose closed-cell foam or rubber that resist UV degradation and moisture.
• Thickness and compression: Strips should compress tightly without losing shape to seal effectively.
• Brand compatibility: Use products recommended or approved by your metal roofing manufacturer.

Summary Table: Key Benefits of Using Closure Strips