Effective Use of Furring Strips for Metal Roof Installation and Repair

Furring strips play a crucial role in metal roof installations and repairs by creating a secure base for attaching roofing materials. These thin strips of wood or metal help level surfaces, provide ventilation, and improve insulation under metal roofing. This article explores how furring strips enhance metal roof performance, their installation techniques, and best practices to maximize durability and weather resistance.

Aspect	Description
Purpose	Establishing a level and ventilated substrate for metal roofing
Materials	Wood (typically treated pine) or metal strips
Benefits	Improved airflow, insulation, moisture control, and secure panel attachment
Installation	Attached perpendicular to roof rafters or roof deck
Applications	New metal roofs, retrofit projects, and repairing damaged roofs

The Role of Furring Strips in Metal Roof Systems

Furring strips are narrow strips of wood or metal fastened to roof decking or framing. Their primary function is to create a level surface for metal roofing panels when the underlying structure is uneven or when additional airflow is needed beneath the metal roof.

These strips raise the metal panels slightly above the deck, allowing space for insulation or ventilation. This ventilation layer helps reduce heat buildup, prevents moisture condensation, and minimizes the risk of rust or mold.

Materials Used for Furring Strips in Metal Roofs

Common materials for furring strips include:

• Treated Wood Strips: Typically made from pressure-treated pine or cedar to resist rot and insects.
• Metal Strips: Steel or aluminum strips offer enhanced durability and fire resistance, especially useful in areas prone to wildfires.

Using treated wood remains popular due to availability and cost-effectiveness, but metal strips are gaining preference for their longevity and compatibility with metal roofing.

Benefits of Using Furring Strips Under Metal Roofing

Furring strips provide several advantages in metal roof installations:

• Improved Ventilation: The gap created between the metal panels and roof deck allows air circulation, reducing heat and moisture accumulation.
• Enhanced Insulation: Space beneath strips can house insulation materials, boosting energy efficiency by maintaining indoor temperatures.
• Level Surface Creation: They compensate for irregularities in the roof deck, ensuring metal panels are installed flush and securely.
• Prevents Water Damage: Elevated panel installation reduces the risk of water infiltration and subsequent damage to sheathing.

Steps for Installing Furring Strips on a Metal Roof

Correct installation of furring strips is essential for metal roof performance. The following outlines the step-by-step process:

1. Inspect the Roof Deck: Evaluate for damage, moisture, or uneven areas that need repair before furring strip installation.
2. Select Furring Strip Material: Choose wood or metal strips based on project requirements and environmental conditions.
3. Measure and Cut Strips: Cut strips to the roof’s width, ensuring consistent sizing for even panel attachment.
4. Attach Strips Perpendicularly: Fasten the strips perpendicular to roof rafters or decking using corrosion-resistant screws or nails.
5. Space the Strips Evenly: Typical spacing ranges from 16 to 24 inches, depending on metal panel size and local building codes.
6. Check for Levelness: Use a level to confirm strips provide an even surface for metal panels.

Common Applications and Situations for Furring Strips

Furring strips are widely used in various metal roof scenarios to improve installation quality and roof longevity.

New Metal Roof Installations

When installing metal roofing on uneven or older surfaces, furring strips help create a uniform base that maximizes fastening strength and reduces roofing material wear.

Retrofitting Existing Roofs

Furring strips allow placing new metal roofing over old shingles or uneven sheathing, improving insulation and ventilation without expensive tear-offs.

Roof Repair and Maintenance

In damaged roof sections, these strips can assist in leveling surfaces, securing replacement panels, and enhancing structural integrity.

Considerations When Choosing and Installing Furring Strips

Several factors influence selecting and installing furring strips for metal roofing:

• Moisture Resistance: Use treated wood or metal strips to prevent rot and corrosion.
• Compatibility: Choose strip material that works well with the metal roofing material to avoid galvanic corrosion.
• Building Code Compliance: Follow local building codes for strip spacing, fastening, and fire safety specifications.
• Weight and Load Support: Ensure strips and fasteners support the metal panel weight and expected environmental loads (snow, wind).

Maintenance Tips for Furring Strips on Metal Roofs

Proper maintenance extends the functionality of furring strips and the metal roofing system:

• Inspect strips periodically for signs of rot, warping, or corrosion.
• Ensure fasteners remain secure and replace any rusted or loose screws.
• Clean gutters and roof valleys to prevent water buildup near strips.
• Repaint or reseal wooden strips periodically to maintain moisture resistance.

Cost Factors and Economic Benefits of Using Furring Strips

The upfront cost of furring strip materials and installation can vary but offers long-term savings by extending the life of metal roofing. Benefits include:

• Reduced need for roof repairs due to improved ventilation and moisture control.
• Lower energy bills from better insulation and reduced heat transfer.
• Minimized structural damage due to even load distribution on roofs.

Wood furring strips are generally more cost-effective, while metal strips offer greater durability with a higher initial investment.

Innovations and Trends in Furring Strip Use for Metal Roofs

Modern construction incorporates advanced materials and techniques for improved furring strip performance:

• Composite Furring Strips: Made from recycled plastics combined with wood fibers, resisting rot and reducing environmental impact.
• Factory-Pretreated Strips: Enhanced for fire resistance and corrosion protection before installation.
• Integration with Solar Panels: Furring strips designed to support metal roofing combined with solar panel mounts.

These innovations address durability and sustainability concerns in roofing applications.

Summary Table: Furring Strip Characteristics and Benefits

Characteristic	Wood Furring Strips	Metal Furring Strips
Durability	Moderate, requires treatment to resist rot	High, corrosion-resistant with coatings
Cost	Lower initial cost	Higher initial cost
Fire Resistance	Lower, depends on treatment	High, non-combustible
Installation Ease	Simple with standard tools	Requires specific fasteners and tools
Environmental Impact	Natural, biodegradable	Recyclable metals