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Florida Roofing Underlayment Requirements (2023 Guide)

Your roof is designed to protect your home from the elements, and in a state like Florida, where the weather can be particularly challenging, it’s crucial to ensure that your roofing system is built to withstand the unique climate conditions.

One essential component of a robust and resilient roof is the underlayment. In this blog post, we’ll explore:

  • What underlayment is and what it does
  • The weather conditions that affect roofs in Florida
  • The specific Florida roofing underlayment requirements

Don’t waste your time trying to understand the Florida building code! Instead, let us make understanding underlayment requirements simple!

A house in Florida

What Is Underlayment, and What Does It Do?

Underlayment is a critical layer of material that is installed beneath the roofing shingles or other roofing materials. Its primary purpose is to provide an extra layer of protection to your roof by serving several key functions:

  • Water Resistance: Underlayment acts as a waterproof barrier, preventing water from infiltrating your roof and causing damage to your home’s structure. This is particularly important in Florida, where heavy rainfall and frequent storms are common.
  • Moisture Management: Underlayment helps manage moisture that may accumulate on your roof, whether from rain, condensation, or other sources. It helps channel water away from vulnerable areas and reduces the risk of mold and rot.
  • Temperature Regulation: Underlayment can provide some degree of insulation, helping to regulate the temperature in your attic space. In Florida’s hot and humid climate, this can be especially valuable for energy efficiency.
  • Protection Against Wind-Driven Rain: In hurricane-prone Florida, wind-driven rain can pose a significant threat to your roof’s integrity. Underlayment helps prevent water intrusion, even during high winds.
  • Secondary Barrier: Underlayment serves as a secondary layer of protection in case of shingle or roofing material damage. It helps keep your home watertight until repairs can be made.

5 Types of Underlayment

A roll of roofing underlayment

When it comes to underlayment for your roof in Florida, there are several types to choose from, each with its own advantages and suitability for specific situations. Here are some common types of underlayment materials:

1) Asphalt-Saturated Felt (ASF):

Asphalt-saturated felt, also known as roofing felt or tar paper, is a traditional underlayment material. It is made from organic or fiberglass mat saturated with asphalt and coated with a fine mineral finish.

ASF is widely used for its cost-effectiveness and versatility. It provides good water resistance and is suitable for most roofing applications. While it is a reliable choice, it may not offer the same level of durability and high-temperature resistance as some synthetic alternatives.

2) Synthetic Underlayment:

Synthetic underlayment is gaining popularity in Florida and elsewhere due to its superior performance characteristics. Made from materials like polyethylene or polypropylene, synthetic underlayment is lightweight, durable, and highly resistant to moisture. It also boasts excellent UV resistance.

Synthetic underlayment is an excellent choice for hurricane-prone areas like Florida, as it offers enhanced wind and water resistance. It is available in various thicknesses and grades to suit different roofing applications.

3) Rubberized Asphalt Underlayment:

Rubberized asphalt underlayment combines the flexibility of rubber with the durability of asphalt. It provides excellent waterproofing and is highly resistant to extreme weather conditions, making it a good choice for Florida’s climate.

This type of underlayment adheres well to the roof deck, reducing the risk of wind-driven rain infiltration. It also offers good thermal insulation and UV resistance.

4) Peel-and-Stick Underlayment:

Peel-and-stick underlayment, also known as self-adhering or self-sealing underlayment, is designed for easy installation. It has a peel-away backing that exposes an adhesive layer, allowing it to bond directly to the roof deck.

This type of underlayment provides an airtight and watertight seal, making it particularly suitable for flat and low-slope roofs. It offers excellent protection against wind-driven rain and is commonly used in coastal areas like Florida.

5) High-Temperature Underlayment:

High-temperature underlayment is designed to withstand the intense heat that Florida’s climate can generate. It is often used in conjunction with metal roofing systems or in areas with high sun exposure.

This type of underlayment is typically reinforced and has a higher melting point, ensuring it remains effective in extreme conditions.

When selecting the right underlayment for your Florida roof, it’s important to consider factors such as your roof’s slope, the roofing material being used, and the specific weather challenges in your region. Consulting with a professional roofing contractor can help you make an informed choice based on your unique requirements.

Weather Conditions That Affect Roofs in Florida

Florida’s climate presents unique challenges for roofing systems. Understanding the specific weather conditions can help you appreciate the importance of underlayment in this region:

  • Heavy Rainfall: Florida experiences a high amount of rainfall, especially during the summer months. Without proper underlayment, water can seep into your roof and cause extensive damage over time.
  • Hurricanes and Tropical Storms: Florida is vulnerable to hurricanes and tropical storms, which can bring not only strong winds but also torrential rain. Underlayment is crucial for protecting your home during these extreme weather events.
  • High Humidity: Florida’s humidity levels are consistently high, which can create an environment conducive to mold and rot. Underlayment helps manage moisture and prevent these issues.
  • Intense Sunlight: The Sunshine State lives up to its name with plenty of sunshine year-round. UV radiation from the sun can deteriorate roofing materials over time, and underlayment can provide an extra layer of defense against this.
  • Temperature Fluctuations: Florida’s temperatures can vary widely, with hot summers and mild winters. Underlayment can help regulate the temperature in your attic, reducing the strain on your HVAC system.

8 Requirements for Underlayment in Florida

Given the unique weather conditions in Florida, there are specific requirements for underlayment to ensure your roof’s durability and longevity:

1) Material Choice:

Underlayment materials suitable for Florida’s climate include asphalt-saturated felt, synthetic materials like polyethylene, and rubberized asphalt. These materials offer excellent water resistance and durability.

2) Water Resistance:

The primary function of underlayment in Florida is to keep water out. Roofing codes typically require underlayment to have a water resistance rating of at least 2.5 pounds per square foot. Additionally, it should meet ASTM D226 and ASTM D4869 standards.

3) Installation Method:

Proper installation is crucial for underlayment effectiveness. It should be installed with a 2-inch overlap, with seams sealed to prevent water infiltration. A drip edge should also be installed to help direct water away from the fascia.

4) Wind Uplift Resistance:

Florida’s frequent storms necessitate underlayment that can withstand strong winds. The underlayment should be rated for wind uplift resistance and comply with local building codes, which often require adherence to the Florida Building Code (FBC).

5) High-Temperature Performance:

Florida’s scorching summers can lead to high attic temperatures. Underlayment should have a high-temperature rating to prevent warping or degradation. Look for products that meet the ASTM D4869 Class V standard.

6) UV Resistance:

To protect against the harsh Florida sun, choose underlayment with UV resistance. Some synthetic underlayment materials have superior UV resistance properties.

7) Building Code Compliance:

Always ensure that your roofing system, including the underlayment, complies with local building codes. Florida’s building codes are designed to address the state’s specific weather challenges, and adherence is essential for safety and insurance purposes.

8) Professional Installation:

Hiring a licensed and experienced roofing contractor is crucial to ensure that your underlayment is installed correctly. Proper installation is key to the underlayment’s effectiveness in protecting your home.

Leave It To the Pros!

In Florida, where the weather can be both beautiful and challenging, your roof plays a vital role in keeping your home safe and comfortable. Underlayment is an essential component of your roofing system, providing protection against heavy rainfall, hurricanes, humidity, and intense sunlight. To meet Florida’s unique requirements, choose the right underlayment material, ensure proper installation, and adhere to local building codes.

Got a question? Greentek Roofing is here to help. Contact us today to learn how to craft a durable roof that is up to code.


“GreenTek was awesome to work with. My rep James was easy to get in contact with and answered all my questions and made the process quick and smooth. The roof came out great and everything was finished on time and they handled everything with my insurance company so I didn’t have to. It made the process stress free for me.”

-Dylan O.

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