When most homeowners think about a roof replacement, they picture brand-new shingles. However, one of the most important parts of the roofing system is hidden underneath those shingles. Roofing felt, often referred to as underlayment, provides a secondary layer of protection that helps keep water out if moisture gets past the shingles. Choosing the right underlayment can make a significant difference in the performance and lifespan of your new roof.
Traditional Asphalt-Saturated Felt
For many years, asphalt-saturated felt was the standard underlayment used beneath asphalt shingles. It is commonly available in 15-pound and 30-pound varieties. While both provide an additional moisture barrier, 30-pound felt is thicker and more durable than 15-pound felt, making it more resistant to tearing during installation.
Traditional felt still performs well on many roofing systems, but it can absorb moisture and wrinkle if exposed to the weather for extended periods before shingles are installed.
Synthetic Roofing Underlayment
Today, many professional roofing contractors install synthetic underlayment because it offers several advantages over traditional felt. Synthetic products are lightweight, extremely durable, water-resistant, and much more resistant to tearing during installation. They also provide better traction for roofing crews, improving safety while working on steep roofs.
Another benefit is that synthetic underlayment can often withstand temporary weather exposure better than traditional felt if installation is interrupted by changing weather conditions.
Ice and Water Barrier
Although technically different from standard felt, ice and water barrier is another important underlayment used during roof replacement. This self-adhering waterproof membrane is installed in the most vulnerable areas of the roof, including eaves, valleys, around chimneys, skylights, and roof penetrations.
Ice and water barriers create a watertight seal around roofing nails and help prevent leaks caused by ice dams, wind-driven rain, and melting snow. In Northeast Ohio, this additional layer of protection is especially valuable because of heavy snowfall and repeated freeze-thaw cycles.
High-Temperature Underlayments
Some roofing systems, particularly metal roofs or specialty roofing products, may require high-temperature underlayments. These products are designed to perform under increased heat while maintaining excellent moisture protection and durability.
Why Underlayment Matters
Underlayment serves as the roof’s backup protection. If shingles are damaged during a storm or blown off by high winds, the underlayment helps prevent water from immediately reaching the roof deck. It also protects the decking during the installation process before the finished roofing materials are in place.
A quality roof replacement includes much more than shingles. Properly installed underlayment, ice and water barriers, flashing, ventilation, and drip edge all work together as one complete roofing system. Choosing the appropriate underlayment for your home and local climate helps maximize the lifespan of your roof while providing dependable protection through every season.
Although homeowners rarely see the felt or underlayment after the roof is completed, it remains one of the most important components hidden beneath the shingles. Investing in high-quality underlayment today helps ensure your new roof is built to withstand years of rain, snow, wind, and changing weather conditions.
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