In the realm of roofing, the underlayment is the unsung hero, providing an essential layer of protection between the roof deck and the external elements. For tile roofs, which are celebrated for their durability and aesthetic appeal, choosing the right underlayment is crucial to ensure the longevity of the roofing system. This comprehensive guide delves into the intricacies of tile roof underlayment, including types, costs, and key considerations for homeowners planning a replacement.

The Role of Underlayment in Tile Roofing Systems

Underlayment serves as a critical barrier against water infiltration, protecting the roof deck from moisture damage and enhancing the overall performance of the tile roof. Given the substantial lifespan of tile roofs, selecting a high-quality underlayment that matches the durability of the tiles is imperative to avoid premature failures and costly repairs.

Types of Tile Roof Underlayment

The choice of underlayment material can significantly impact the protection level, lifespan, and cost of the roofing system. The primary types of underlayment used in tile roofing include:

Asphalt-Saturated Felt: A time-tested option, felt underlayment offers basic water resistance and is favored for its cost-effectiveness. However, it may not provide the same level of durability and protection as more advanced materials.

Rubberized Asphalt: Offering superior waterproofing capabilities, rubberized asphalt underlayment adheres directly to the roof deck, creating a watertight seal that is highly resistant to water and temperature fluctuations.

Synthetic Underlayment: Made from polypropylene or polyester, synthetic underlayment is lightweight, tear-resistant, and provides excellent moisture protection. Its UV resistance also allows for longer exposure during the roofing process.

Cost Considerations for Tile Roof Underlayment Replacement

The cost of replacing underlayment on a tile roof varies based on several factors, including the type of underlayment, roof size and complexity, and regional labor rates. On average, homeowners can expect to encounter the following costs:

Asphalt-Saturated Felt: Ranges from $0.15 to $0.55 per square foot, making it the most budget-friendly option.

Synthetic Underlayment: Costs between $0.25 to $0.65 per square foot, offering a balance between performance and price.

Rubberized Asphalt: The most expensive option, ranging from $0.25 to $0.75 per square foot, due to its enhanced durability and waterproofing capabilities.

It’s important to note that these costs are for the underlayment material alone and do not include labor or additional expenses related to the removal of existing tiles or repairs to the roof deck.

When to Replace Tile Roof Underlayment

The lifespan of tile roof underlayment varies, but it generally lasts between 20 to 30 years. Signs that indicate the need for replacement include visible leaks, water stains on the ceiling, or damaged tiles. Regular inspections by a professional can help determine the condition of the underlayment and whether replacement is necessary.

Factors Influencing the Total Cost

Several variables can affect the total cost of underlayment replacement for a tile roof:

Roof Scale and Complexity: Bigger and intricate roofs demand additional resources and workforce, thereby escalating the total expenditure.

Regional Labor and Material Expenses: Costs fluctuate depending on the locality, with certain regions experiencing elevated rates for labor and materials.

Roof State: Pre-existing damages to the roof foundation or framework might mandate repairs prior to laying down the new underlayment, thereby increasing the project’s expenses.

Making an Informed Decision

Choosing the right underlayment for your tile roof involves weighing the benefits and costs of each option. Consider factors such as the local climate, the expected lifespan of the roofing system, and budget constraints. Consulting with a professional roofing contractor can provide valuable insights and ensure that the selected underlayment meets your specific needs.


The underlayment is a vital component of any tile roofing system, offering protection against moisture and extending the roof’s lifespan. By understanding the different types of underlayment, associated costs, and factors affecting replacement, homeowners can make informed decisions that ensure the long-term integrity of their roofs. At Planet Roof, located in Mcmurray, PA, our expertise in roofing solutions enables us to guide homeowners through the process of selecting and installing the ideal underlayment for their tile roofs, ensuring optimal performance and durability.