When it comes to protecting your roof, choosing the right underlayment is crucial. Many homeowners and contractors often encounter the terms roofing felt and tar paper, sometimes used interchangeably but with subtle differences. Both materials serve as protective layers beneath shingles to improve waterproofing and durability.
This guide explains the distinctions between roofing felt and tar paper, their benefits, drawbacks, and best applications, helping American homeowners make informed decisions during roof installation or repair projects.
| Feature | Roofing Felt | Tar Paper |
|---|---|---|
| Material | Typically fiberglass or organic felt soaked in asphalt | Heavy paper saturated with tar or asphalt |
| Water Resistance | High water resistance but can absorb moisture with time | Good water resistance but less durable in extended exposure |
| Weight | Lighter, easier to handle | Heavier, more rigid |
| Durability | More durable, less prone to tearing | Less durable, prone to cracking and tearing |
| Cost | Generally more expensive | Typically lower cost |
What Is Roofing Felt?
Roofing felt is a ubiquitous underlayment material used in roofing applications. It consists of a base mat made primarily from organic or fiberglass materials that are saturated with asphalt to provide waterproofing.
Roofing felt typically comes in rolls of varying thicknesses, commonly known as 15-pound or 30-pound felt, referring to the weight per square. The fiberglass-based felt is now often preferred over organic felt due to its enhanced strength and resistance to mold.
Modern roofing felt offers superior tear resistance, easy installation, and better protection against weather elements, making it a popular choice among roofing professionals and DIY homeowners alike.
Understanding Tar Paper
Tar paper is an older roofing underlayment material composed of heavy paper soaked in tar or asphalt. It is less flexible and heavier than roofing felt.
Historically, tar paper served as the primary moisture barrier in roofing systems before advancements in underlayment technology introduced fiberglass-based felts and synthetic options.
While still used in some regions and applications due to its low cost, tar paper tends to be less durable and can degrade faster when exposed to prolonged moisture or sunlight, impacting its effectiveness over time.
Key Differences Between Roofing Felt and Tar Paper
- Material Composition: Roofing felt uses fiberglass or organic mats with asphalt saturation, while tar paper is essentially heavy paper coated with tar.
- Durability: Roofing felt generally withstands tearing, moisture, and weather better compared to tar paper, which can crack and degrade.
- Weight and Flexibility: Roofing felt is lighter and more flexible, facilitating easier handling and installation; tar paper is heavier and more rigid.
- Water Resistance: Both provide a moisture barrier, but roofing felt offers enhanced resistance to water penetration and mold growth.
- Cost: Tar paper tends to be less expensive, but roofing felt’s longer lifespan may offer better value.
- Environmental Impact: Some roofing felts now incorporate recyclable fiberglass, whereas tar paper’s heavy paper base has different environmental considerations.
Benefits of Using Roofing Felt
Roofing felt is valued for its balance of protection, ease of use, and durability. Its key benefits include:
- Superior Tear Resistance: Fiberglass felts resist tearing even under strong winds during installation.
- Better Waterproofing: Asphalt saturation creates a robust barrier against rain and moisture infiltration.
- Mold Resistance: Fiberglass mats do not retain water, reducing the chances of mold and mildew growth.
- Fire Resistance: Fiberglass roofing felt has a higher fire rating compared to organic or tar paper materials.
- Lightweight and Easy to Install: Thin, flexible rolls make installation quick and less labor-intensive.
Benefits and Drawbacks of Tar Paper
Tar paper remains in limited use due to its low cost and traditional application in roofing underlayments. Its benefits include:
- Affordable Material: Cost-effective for budget-conscious projects.
- Simple Moisture Barrier: Provides basic water resistance under shingles.
However, tar paper comes with significant drawbacks:
- Prone to Cracking and Tearing: Brittleness over time causes failures.
- Heavier and Harder to Handle: Makes installation laborious.
- Limited Longevity: Degrades faster with sun exposure and moisture.
- Less Fire-Resistant: More combustible than fiberglass felt.
Choosing the Right Underlayment for Your Roof
Selecting between roofing felt and tar paper depends on specific project needs, budget, and desired durability.
Roofing felt is recommended for most residential and commercial roofing projects due to its enhanced protection, longevity, and ease of handling. The additional investment often pays off with fewer repairs and increased roof performance.
Tar paper might be appropriate for low-budget or temporary roofing solutions where long-term durability is less critical.
It is also important to confirm local building codes and manufacturer compliance, as some jurisdictions require specific underlayment standards for fire resistance and waterproofing.
Installation Considerations for Roofing Felt and Tar Paper
Proper installation is essential to maximize the effectiveness of either underlayment. Key points include:
- Roll Orientation and Overlap: Both materials should be laid horizontally with sufficient overlap (usually 2-4 inches) to prevent water intrusion.
- Securing the Material: Use roofing nails or staples specifically designed to avoid damage; improper fastening can cause tears, especially in tar paper.
- Protection During Installation: Avoid walking heavily on the underlayment to prevent punctures or tears.
- Weather Conditions: Installation should be completed under dry conditions to ensure optimal adhesion and protection.
Environmental and Safety Aspects
Roofing felt, especially fiberglass types, are becoming more environmentally friendly due to the use of recyclable materials and reduced toxic emissions during manufacturing.
Tar paper involves tar, a petroleum-based product with associated environmental and health concerns during production and disposal.
From a safety perspective, fiberglass roofing felt generally offers better fire resistance and mold resistance, contributing to a healthier roofing environment.
Alternatives to Roofing Felt and Tar Paper
In addition to traditional roofing felt and tar paper, newer synthetic underlayments have gained popularity due to their superior durability and performance.
- Synthetic Underlayment: Lightweight, tear-resistant, water-resistant, and often with UV protection for longer outdoor exposure.
- Peel and Stick Membranes: Self-adhesive waterproof layers that provide excellent sealing but at a higher cost.
- Rubberized Asphalt Membranes: High-quality waterproof barriers typically used in challenging environments.
While these alternatives are increasingly favored, knowing the differences between roofing felt and tar paper remains important for evaluating options based on project needs.