Underlayment is one of the most important protective components in any roofing system, even though it is rarely seen once the roof is completed.
At Providence Roofing, we consider underlayment a critical layer of defense that helps keep homes and buildings protected from moisture, wind-driven rain, and long-term roofing damage.
While shingles or metal panels are the most visible parts of a roof, underlayment is what provides essential backup protection beneath the surface.
Roofing underlayment is a protective barrier installed directly on top of the roof deck, underneath the final roofing material. It is typically made from synthetic materials or asphalt-based felt and serves as an added waterproof layer between the roof structure and the exterior elements.
Once installed, the underlayment covers the entire decking area before shingles, tiles, or metal roofing panels are placed above it. This layer plays a major role in preventing moisture from reaching the wood framing or interior of the building.
The primary purpose of underlayment is to act as a moisture-resistant shield. Roofing systems are designed to shed water, but no roof is completely immune to heavy storms, ice buildup, or wind-driven rain. Underlayment provides an extra level of protection in case water slips past the outer roofing material.
Key functions of underlayment include:
Underlayment is installed directly on top of the roof sheathing, which is usually plywood or OSB decking. It is positioned beneath all exterior roofing materials, making it the second layer of the roof system after the deck itself.
Because it spans the full roof surface, underlayment plays a role in protecting every section of the roof, including:
Underlayment is especially important in vulnerable areas where water collects or flows heavily.
There are several types of underlayment used depending on roof design, climate, and material choice:
Often called felt paper or tar paper, this traditional underlayment has been used for decades. It provides basic moisture protection and is cost-effective, though it is less durable than modern synthetic options.
Made from advanced polymer materials, synthetic underlayment is lighter, stronger, and more resistant to tearing. It performs well in harsh weather and is now one of the most common choices for residential and commercial roofing.
This peel-and-stick membrane is used in high-risk areas, especially in valleys and along roof edges. It offers superior waterproofing and is essential in regions prone to ice dams or heavy rainfall.
At Providence Roofing, we help select the best underlayment based on the roof type and local conditions.
Underlayment may not be visible once the roof is complete, but it plays a major role in the roof’s long-term reliability. Without proper underlayment, even a high-quality roof can become vulnerable to leaks and hidden damage.
It also supports proper installation by creating a smooth surface for shingles and helping ensure consistent performance across the entire roof structure.
Proper underlayment installation requires skill and attention to detail. Seams must be overlapped correctly, fasteners must be placed properly, and vulnerable sections of the roof need additional waterproof layers.
At Providence Roofing, we treat underlayment as a core part of every roofing system, not an afterthought. Our team ensures every roof has the right protective foundation to handle years of weather exposure.
Underlayment is one of the most valuable components of a durable roof, providing hidden protection that keeps your home safe, dry, and structurally sound for the long haul.
