When it comes to roofing, there’s much more to consider than just shingles and flashing. The underlayment you choose can make a significant difference in the longevity and performance of your roof. In this blog, we’ll explore three popular roofing underlayment options: 30lb felt, synthetic felt, and wind and water shield. By the end, you’ll have a clear understanding of each, helping you make an informed decision for your roofing project.

1. 30lb Felt:

30lb felt, also known as asphalt-saturated felt paper, has been a staple in roofing for decades. Here’s what you need to know about it:


  • Affordability: 30lb felt is one of the most budget-friendly options, making it an attractive choice for many homeowners.
  • Water Resistance: It provides a good level of water resistance and can protect your roof deck from moisture intrusion.
  • Familiarity: Many roofing contractors are well-acquainted with 30lb felt, making it easy to install correctly.


  • Weight: As the name suggests, it’s quite heavy, which can make the installation process more labor-intensive.
  • Limited Breathability: It doesn’t allow for optimal ventilation, potentially causing moisture buildup.
  • Durability: While it offers decent protection, it may not be as durable as some newer alternatives.

2. Synthetic Felt:

Synthetic felt, often made from polyethylene or polypropylene, is a modern alternative to traditional felt paper. Let’s dive into its attributes:


  • Lightweight: Synthetic felt is much lighter than 30lb felt, making it easier to handle and install.
  • Durability: It’s known for its resistance to tearing, wrinkling, and moisture, ensuring a longer lifespan.
  • Breathability: Unlike traditional felt, synthetic felt provides better ventilation, reducing the risk of trapped moisture.
  • Eco-Friendly: Some synthetic felts are made from recycled materials, offering an environmentally conscious choice.


  • Cost: It tends to be pricier than 30lb felt, although the added benefits may justify the expense.
  • Less Familiarity: Not all roofing contractors are equally familiar with synthetic felt, so you’ll want to ensure you work with someone experienced in its installation.

3. Wind and Water Shield:

Wind and water shield, often referred to as ice and water shield, is a premium roofing underlayment designed for superior protection. Here’s what sets it apart:


  • Exceptional Waterproofing: Wind and water shield offers unparalleled waterproofing, even in extreme weather conditions.
  • Self-Sealing: It has a self-adhesive backing that seals around nails and fasteners, preventing water infiltration.
  • Flexibility: This underlayment can be used in critical areas of the roof, such as valleys, eaves, and around roof penetrations.
  • Extended Lifespan: Its robust construction typically translates to a longer lifespan for your roof.


  • Cost: Wind and water shield is the most expensive option among the three, but its premium qualities can be worth the investment.
  • Installation Expertise: Proper installation is crucial, so it’s essential to work with a knowledgeable roofing contractor.


Choosing the right roofing underlayment is a vital step in ensuring the longevity and performance of your roof. 30lb felt, synthetic felt, and wind and water shield each have their unique advantages and disadvantages. Your decision should depend on factors like your budget, climate, and the level of protection you require.

In summary, 30lb felt is a cost-effective choice, synthetic felt offers durability and breathability, while wind and water shield provides top-notch protection against the elements. To make an informed decision, consult with a professional roofer who can assess your specific needs and recommend the most suitable underlayment for your roofing project. Remember, a well-chosen underlayment is the foundation of a long-lasting and reliable roof.