Roofing Tar Paper Cost and Installation Guide

Roofing tar paper, commonly known as roofing felt, is a foundational material used under shingles to provide moisture protection and a stable base. Understanding the cost of tar paper helps homeowners estimate project expenses accurately and compare options among felt grades and installation methods. This guide covers price ranges, materials, and practical tips to help homeowners plan a roofing project efficiently.

What Is Tar Paper And Why It Matters

Tar paper is an asphalt-saturated felt used as an underlayment in many roofing systems. It serves as a secondary barrier against moisture, protects the roof decking during installation, and aids in weather resistance when shingles are absent or damaged. Tar paper comes in different weights and weather-performance ratings, which influence cost as well as durability in varied climates. Knowing the role of tar paper helps justify the investment and choosing the right type for a given roof helps avoid premature leaks and repairs.

Common Types And Their Costs

Tar paper is typically sold as rolls or bundles and priced by square foot or per roll. The most common types are 15-pound and 30-pound asphalt-saturated felts, with newer synthetic underlayments offering higher performance at different price points. In most residential projects, 15-pound felt is the baseline option, while 30-pound felt provides greater tear resistance and longer life in exposed or high-traffic roof decks. Synthetic underlayments, which are lighter and more durable, may cost more upfront but can offer labor savings and better performance in severe weather.

Typical cost ranges for tar paper materials (before tax and installation):

15-pound asphalt-saturated felt: $0.20 to $0.50 per square foot
30-pound asphalt-saturated felt: $0.40 to $0.90 per square foot
Synthetic underlayments (high-performance): $0.50 to $1.50 per square foot
Per-roll costs vary by width and length; common widths are 3 feet or more, with roll lengths of 100 to 400 feet

Note: One “square” of roofing is 100 square feet. Pricing is often quoted per square or per roll, so converting to squares helps align with typical roofing bids. For example, a 3-foot-wide roll that is 36 feet long yields 108 square feet, costing roughly $22 to $90 depending on the type.

Factors That Influence Tar Paper Pricing

Several variables affect the final tar paper cost for a roofing project:

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Material type (felt vs. synthetic, 15-pound vs. 30-pound) and brand
Roof area total square footage drives the number of rolls needed
Roof pitch and complexity, which can affect waste and labor, indirectly affecting cost
Local building codes requirements, which may require specific underlayment types in certain climates
Climate exposure—areas with heavy rain, wind, or snow may justify higher-performance underlayments
Labor availability and regional price variations for roofing contractors

Estimating Costs For A Typical Project

To estimate tar paper costs, start with the roof’s area and select the underlayment type. Calculate rolls needed and multiply by the price per roll or per square foot. Example: A 1,500-square-foot roof using standard 15-pound felt at $0.30 per square foot would require approximately 15 rolls of 3-foot-wide material to cover 1,500 square feet, translating to about $450 in underlayment material before tax and disposal. If a higher-grade 30-pound felt or synthetic underlayment is chosen, the material cost could rise to $900–$2,250 for the same roof area, depending on product specifications.

When budgeting, consider waste: most roofers plan for 5–10% waste due to overlaps, cuts, and complex roof lines. Labor adds a separate cost category, often calculated per square foot or per square, and can vary by region. It’s common for the underlayment portion of a roofing job to account for 5% to 15% of total material expenses, depending on roof complexity and local labor rates.

Where To Buy Tar Paper And What To Look For

Tar paper and underlayments are widely available at home improvement centers, roofing supply stores, and online retailers. When buying, consider the following:

Refunds and warranties—look for product warranties and supplier return policies
Warranty compatibility—ensure the underlayment is compatible with the roof covering (asphalt shingles, metal, tile, etc.)
UV resistance—some felts break down quickly under prolonged sun exposure before installation
Installation guidelines—some products require specific nailing patterns or overlaps for performance

Installation Basics And How It Affects Cost

Underlayment installation is generally straightforward but requires proper alignment and overlap to prevent leaks. Typical practices include:

Installing from the eave to the ridge with an overlap of 2 to 4 inches
Shingle-style overlay for asphalt shingles to shed water effectively
Securing the underlayment with nails or staples, following manufacturer guidelines
Ensuring a dry, clean decking surface before application

Labor considerations can significantly impact total costs. A professional roofer may factor in removal of old roofing, decking inspection, and any repair work needed prior to applying underlayment. In areas with severe weather, specialized installation methods may increase labor time and cost but improve long-term performance.

Maintenance, Longevity, And Alternatives

Tar paper is not a permanent weatherproofing layer on its own. Over time, exposure to moisture and sun can degrade felt underlayment, especially if the roof is not properly vented or shingles are damaged. Regular maintenance, including inspecting for lifted edges or tears after storms, helps catch issues early. In some climates, builders increasingly use synthetic underlayments or self-adhering membranes, which can extend life and improve ease of installation, albeit at higher upfront cost.

Alternatives to traditional tar paper include: