Best Felt Paper Options for Roofing: Types, Benefits, and Installation Tips
Choosing the best felt paper for roofing is essential to protect your home from water damage, enhance roof durability, and meet building code requirements. Felt paper acts as a critical moisture barrier beneath roofing materials, preventing leaks and improving insulation.
| Type of Felt Paper | Material Composition | Weight (lb per 100 sq ft) | Key Benefits | Common Uses |
|---|---|---|---|---|
| Asphalt-Saturated Felt | Organic or fiberglass base saturated with asphalt | 15 or 30 | Reliable moisture barrier, affordable, easy to install | Standard underlayment for shingle roofs |
| Synthetic Felt | Polypropylene or polyester materials | Varies (often lighter than asphalt felt) | Improved durability, tear resistance, lightweight | Modern underlayment for shingles and metal roofs |
| Rubberized Asphalt Membrane | Rubberized asphalt with a peel-and-stick backing | Varies | Superior waterproofing, self-adhesive, excellent for valleys | Critical area protection and high-slope roofs |
Understanding the Role of Felt Paper in Roofing
Felt paper is a protective underlayment installed between the roof deck and the outer roofing material. It offers waterproofing protection, preventing moisture infiltration from rain or melting snow. Felt paper also functions as a secondary defense layer if the primary roofing surface is damaged. It improves the lifespan of the roof by reducing the chance of mold growth and wood rot beneath shingles or tiles.
Furthermore, felt paper enhances fire resistance and assists with roofing code compliance. It provides a slip-resistant surface for roofers during installation.
Types of Roofing Felt Paper
Asphalt-Saturated Felt
Traditional asphalt-saturated felt is made with organic materials like wood fibers or fiberglass mats, soaked in asphalt to make them waterproof. This type is typically available in 15-pound or 30-pound weights—which refer to the weight per 100 square feet.
15-pound felt is lighter and easier to handle but less durable, while 30-pound felt offers better robustness and resistance against tearing and water penetration. Asphalt felt is cost-effective and widely used for residential roofing under shingles.
Synthetic Roofing Felt
Made from polypropylene or polyester, synthetic felt is designed to overcome the shortcomings of asphalt felt. It is lighter, stronger, and more tear-resistant and often comes with enhanced water-shedding capabilities.
This material dries out faster and is less prone to wrinkling or buckling during installation. Some synthetic felts have UV-resistant coatings to allow longer exposure before shingles are installed.
Rubberized Asphalt Membrane
Rubberized asphalt membranes provide an extra layer of waterproofing and typically feature a self-adhesive peel-and-stick backing to ensure tight sealing around roof penetrations, valleys, and edges.
While more costly, this membrane offers the highest level of protection against water intrusion and is commonly used in vulnerable areas or on steep slopes.
How to Choose the Best Felt Paper for Your Roofing Project
Several factors influence the choice of felt paper for roofing:
- Climate Conditions: In areas with heavy rain or snow, opt for synthetic or rubberized membranes for superior waterproofing.
- Roof Type: Asphalt shingles generally pair well with 30-pound felt or synthetic felt. Metal roofs benefit from synthetic due to better durability.
- Budget: Asphalt felt is budget-friendly, while synthetic and rubberized options cost more but provide enhanced performance.
- Local Building Codes: Always check local requirements as some regions mandate specific underlayment types for safety and durability.
- Installation Environment: Synthetic felts are easier and quicker to install and can handle longer exposure to sunlight during construction.
Comparing Roofing Felt Paper: Asphalt vs. Synthetic vs. Rubberized
| Feature | Asphalt Felt | Synthetic Felt | Rubberized Membrane |
|---|---|---|---|
| Water Resistance | Good but can retain water | Excellent quick drying and repel | Superior waterproof seal |
| Tear Resistance | Moderate; easy to rip | High; resists tearing and wrinkling | Very high with adhesive backing |
| Weight | Heavier | Lighter | Varies; heavier due to membrane thickness |
| Cost | Lowest | Medium | Highest |
| UV Exposure Resistance | Limited (must be covered quickly) | Good (some rated for long exposure) | Excellent |
Installation Tips for Roofing Felt Paper
Proper installation of felt paper is crucial for maximizing its protective benefits. Follow these best practices:
- Start with a clean, dry roof deck free of nails, dust, and debris.
- Roll out felt horizontally from the eaves upward to the ridge, overlapping each row by at least 2-4 inches.
- Secure the felt with roofing nails or staples spaced according to manufacturer guidelines, typically every 6-8 inches along overlaps.
- Use special care around chimneys, vents, and valleys by applying additional layers or product-specific membranes.
- Avoid walking excessively on the felt paper to reduce tearing during roofing installation.
Maintenance and Replacement Considerations
Roofing felt paper generally requires no direct maintenance once shingles or other roofing materials protect it. However, when re-roofing or inspecting a roof, check for signs of wear under the shingles such as:
- Rips or tears in visible felt areas
- Signs of water stains or mold beneath roofing materials
- Damage caused by prolonged UV exposure if underlayment was exposed too long
Replacing felt paper during major roofing repairs ensures lasting protection and adherence to roofing warranties.