Types of Underlayment
Metal roof underlayment comes in a few types, and knowing them helps a Delphi homeowner understand the options. Here are the main ones.
Synthetic Underlayment
Synthetic underlayment is a modern material that has largely become the choice for quality metal roof installations, made from durable synthetic materials that resist tearing and hold up well. It offers advantages over traditional felt in durability, performance, and handling. For many quality installations, synthetic underlayment is the standard choice. It provides a tough, reliable secondary barrier beneath the panels. It is the modern, durable option.
Traditional Felt
Traditional felt, an asphalt saturated material, is the older type of underlayment, used for many years before synthetics became common. While it provides a moisture barrier, felt is generally less durable and tear resistant than modern synthetics. Felt is still used in some cases, but for metal roofing, synthetic underlayment is often preferred for its better performance. Felt is the traditional option that synthetics have largely improved upon. It is the older approach.
Self-Adhering Membranes
Self adhering membranes, sometimes called peel and stick, are a type of underlayment that adheres directly to the deck, providing a sealed barrier and often used in specific areas or for added protection. These membranes offer strong moisture protection and can seal around fasteners. They are used where extra protection is wanted, such as in vulnerable areas. Self adhering underlayment provides a robust, sealed barrier. It offers enhanced protection where needed.
High-Temperature Options
For metal roofs, which can get hot in the sun, high temperature rated underlayments are available and important, since the underlayment must withstand the heat beneath a metal roof. Choosing an underlayment rated for the temperatures under metal ensures it performs and lasts. This is a metal specific consideration in selecting underlayment. A high temperature rated product is suited to the conditions beneath metal panels. It handles the heat appropriately.
Choosing Among Them
The right underlayment depends on the roof, the application, and the specifics of your project, and a contractor experienced in metal roofing selects an appropriate, quality underlayment. For most quality metal installations, a durable synthetic, often high temperature rated, is a common choice, with self adhering membranes used where extra protection is warranted. Matching the underlayment to the roof is part of a quality installation. The choice fits the project. A contractor guides it.
The Types, in Short
Underlayment types include modern synthetic, the common choice for quality metal installations, traditional felt, the older option, and self adhering membranes for added protection, with high temperature rated products important beneath hot metal roofs. The right choice fits the project.
It also helps Delphi homeowners to know that underlayment has evolved, and that modern synthetic underlayments have largely become the standard for quality metal roof installations, which is worth understanding when comparing what different contractors propose. For many years, the traditional underlayment was felt, an asphalt saturated material that provided a basic moisture barrier and served adequately, and felt is still used in some applications. But synthetic underlayments, made from durable engineered materials, have become the common choice for quality metal roofing because they offer real advantages, they are generally more durable and far more resistant to tearing than felt, they hold up better over time and under the conditions beneath a roof, and they handle the heat that builds under metal panels well when a high temperature rated product is chosen. In addition to synthetics, there are self adhering membranes, sometimes called peel and stick, which adhere directly to the deck and form a sealed barrier, providing especially strong moisture protection and the ability to seal around fasteners, and these are often used in particularly vulnerable areas or wherever extra protection is warranted. The practical takeaway for a homeowner is not that they need to become an expert in underlayment products or specify them personally, but rather that an experienced, reputable metal roofing contractor will select an appropriate, quality underlayment for the roof, commonly a durable, high temperature synthetic, with added protection where it makes sense, and will install it correctly with proper overlap and detailing. The underlayment a contractor uses and how they install it is one of the quiet indicators of whether they build metal roofs to a high standard or cut corners on the parts that do not show.
One point worth making clear for Delphi homeowners is that the underlayment, although it is a layer you will never see once the roof is finished, is a genuine part of what makes a metal roof perform and last, and it is worth understanding for what it tells you about the quality of an installation. The underlayment is the material that goes down over the roof decking, the plywood or sheathing that forms the roof's surface, before the metal panels are installed on top. Its primary job is to serve as a secondary barrier against moisture, a backup to the metal panels themselves. The metal is the roof's main defense against water, and a properly installed metal roof sheds rain and snow effectively, but the underlayment provides insurance, so that if water ever does get past the panels, from wind driven rain forcing moisture under an edge, from ice, or from any other cause, the underlayment helps keep that moisture from reaching the deck and the home below. By keeping the deck dry, the underlayment also helps protect the structural sheathing the roof is built on, which supports the roof's and the home's longevity over the decades a metal roof serves. Underlayment also provides a smooth, consistent surface over the decking for the panels to be installed on. For metal roofs specifically, there is an added consideration, because metal panels can get quite hot in the sun, the underlayment beneath them needs to be able to withstand that heat, which is why high temperature rated products matter. A quality installation includes proper, appropriate underlayment as a matter of course, so it is a reasonable thing to ask a contractor about when gauging whether they do things right.
One point worth making clear for Delphi homeowners is that the underlayment, although it is a layer you will never see once the roof is finished, is a genuine part of what makes a metal roof perform and last, and it is worth understanding for what it tells you about the quality of an installation. The underlayment is the material that goes down over the roof decking, the plywood or sheathing that forms the roof's surface, before the metal panels are installed on top. Its primary job is to serve as a secondary barrier against moisture, a backup to the metal panels themselves. The metal is the roof's main defense against water, and a properly installed metal roof sheds rain and snow effectively, but the underlayment provides insurance, so that if water ever does get past the panels, from wind driven rain forcing moisture under an edge, from ice, or from any other cause, the underlayment helps keep that moisture from reaching the deck and the home below. By keeping the deck dry, the underlayment also helps protect the structural sheathing the roof is built on, which supports the roof's and the home's longevity over the decades a metal roof serves. Underlayment also provides a smooth, consistent surface over the decking for the panels to be installed on. For metal roofs specifically, there is an added consideration, because metal panels can get quite hot in the sun, the underlayment beneath them needs to be able to withstand that heat, which is why high temperature rated products matter. A quality installation includes proper, appropriate underlayment as a matter of course, so it is a reasonable thing to ask a contractor about when gauging whether they do things right.
Get Quality Underlayment
Delphi Metal Roofing installs metal roofing with quality, appropriate underlayment across Delphi and Carroll County. Call (765) 676-3491 for a free consultation on a metal roof built with the right underlayment for lasting protection.