When it comes to roofing, what you don't see can be just as important as what you do. Roof underlayment, the hidden layer beneath your shingles, serves as a crucial barrier against moisture and provides additional protection for your home. Let's delve into the various types of roof underlayment and their unique features.

Commonly known as felt paper, asphalt-saturated felt is one of the oldest and most traditional underlayment materials. It is made by saturating a felt material with asphalt to create a water-resistant barrier.

Pros: Cost-effective, provides a good level of protection against moisture, and is widely accepted in the roofing industry.

Cons: Susceptible to tearing during installation, and may not be as resistant to UV rays as newer materials.

Made from polyethylene or polypropylene, synthetic underlayment is a modern alternative to traditional felt paper. It is engineered to be more durable and weather-resistant.

Pros: Lightweight, resistant to tearing, and offers superior water resistance. Some products also have UV resistance for prolonged exposure during roof installation.

Cons: Generally more expensive than felt paper, but the added benefits may outweigh the cost for many homeowners.

This type of underlayment is infused with rubberized asphalt to enhance flexibility and water resistance. It often comes with a peel-and-stick adhesive backing for easy installation.

Pros: Provides excellent waterproofing and flexibility, making it suitable for various roofing applications. The peel-and-stick feature simplifies installation and enhances the overall seal.

Cons: Higher cost compared to traditional felt, but the added durability and ease of installation can justify the expense.

Specifically designed for areas prone to ice dams and heavy rainfall, ice and water shield is a self-adhesive membrane that creates a watertight barrier. It is often installed in vulnerable areas like eaves, valleys, and around roof penetrations.

Pros: Offers superior protection against ice dams and water infiltration. The self-adhesive nature ensures a tight seal.

Cons: More expensive than other underlayment options, and its use is often targeted to specific areas rather than the entire roof.

Also known as synthetic roof underlayment with breathable technology, this type allows for moisture vapor to escape while preventing water from entering. It is often used in ventilated roof systems.

Pros: Enhances roof ventilation, preventing the buildup of moisture. Provides a secondary layer of defense against water infiltration.

Cons: May not be necessary for all roofing systems, and its benefits are most pronounced in well-ventilated roofs.