Roofing
Roof Replacement in Dallas, TX

Key Takeaways

  • Underlayment and ice-and-water barrier are not the same thing. Underlayment covers the entire roof deck. An ice and moisture barrier is a heavier form of protection reserved for the places most likely to fail: valleys, around protrusions, along eaves and overhangs, and above roof nails.
  • Synthetic is what most roofers reach for. It’s an asphalt-saturated synthetic coated in fiberglass, highly resistant to rips and tears, and dimensionally stable. Woven reinforcement adds slip resistance for crews. It’s also flexible and breathable, which matters because breathability is what keeps mold from forming underneath.
  • Felt paper is the wrong choice for a low-slope roof. Asphalt-saturated felt is budget-friendly and works on steep slopes where water runs off fast. It’s water-resistant rather than waterproof. It has no adhesive backing, so it gets nailed down and doesn’t always lie flat, which can throw off the shingles above it.
  • Felt’s lack of breathability creates the real problems. Moisture that gets underneath has nowhere to go. That produces mold, mildew, foul odors, curling shingles, and warped substrate, and the damp conditions attract ants, mosquitoes, and other pests into the roof assembly.
  • Most underlayment failures trace back to installation. Shingles laid over underlayment still damp from morning dew won’t adhere properly, which sets up early failure. Heavy foot traffic during installation leaves ridges, wrinkles, and tears. And every type needs several inches of overlap, since gaps there are direct moisture paths.

When it comes to protecting the value, aesthetics, and overall integrity of your Dallas, TX home, few things are as crucial as its roof. This multi-layer system provides a watertight barrier against the outside elements.

It routes moisture toward your downspouts and away from the building. It also provides critical insulation and UV ray protection. Your roof’s underlayment is a key part of this system. The following are seven things every homeowner should know about roof underlayment.

1. Underlayment Is Applied Directly to the Roof Deck

Roof underlayment is a water-resistant material that roofers apply directly to the roof deck before placing shingles, tiles, or any other outer roofing material. Designed to protect roof sheathing, it offers an important, secondary layer of protection against heavy snow loads, rain, snow-melt, and ice. If your roof ever develops problems with loose, lifted, curled, or missing shingles, the underlayment will keep moisture from finding its way into the building.

You may have heard the term “ice and moisture barrier” used as part of a roof’s multi-layer design. Although ice and moisture barriers and roof underlayment both act as moisture shields, the former offer a significantly more robust form of protection. Thus, they are frequently used in the most vulnerable roofing areas, such as:

  • Roof valleys
  • Around roofing protrusions
  • Along eaves and overhangs
  • Above roof nails

More often than not, roofers reserve these applications for places that are most likely to sustain damage from wind-driven rain, ice dams, and pooling water. In comparison, underlayment is applied across the entire roof deck and ice and moisture barriers are found in limited locations.

2. There Are Several Roof Underlayment Options

There are multiple options for roof underlayment. These include:

Each one has its benefits and drawbacks, and some are better-suited to specific roofing types than others. When choosing underlayment, roofers consider factors like the local climate, roof slopes, roofing materials, building codes, and the homeowner’s budget.

Synthetic Underlayment

Synthetic underlayment is the preferred choice among roofers and for most standard applications. Coated in fiberglass, this underlayment is comprised of an asphalt-saturated synthetic material that’s both highly resistant to rips and tears and highly stable. For added slip resistance, synthetic underlayment can additionally have a woven reinforcement.

Many synthetic underlayment options are affordably priced. This material is also flexible and breathable. These attributes allow for easy and error-free installation while preventing roof mold.

Asphalt-Saturated Felt Paper

Also known as felt paper or tar paper, asphalt-saturated felt is a budget-friendly choice. However, although it’s water-resistant, asphalt-saturated felt falls short of being completely waterproof. This material works well on steeply sloped roofs with enough rise to promote rapid runoff, but it isn’t a great choice for flat roofs or low-sloped structures. Lacking an adhesive backing, felt underlayment is nailed down. As a result, it doesn’t always lie completely flat and may affect the position and efficacy of the overlying shingles or tiles.

Another important drawback of asphalt-saturated felt paper is its lack of breathability. When moisture finds its way beneath these applications, it can fester and cause problems like:

Trapped moisture can additionally create the ideal conditions for ants, mosquitoes, and other common rooftop pests.

Rubberized Underlayment

Comprised of rubberized asphalt, rubberized underlayment provides excellent waterproofing. However, it’s also the most expensive underlayment type. It comes with an adhesive backing that allows for quick, easy, and seamless installation. This creates a flat, waterproof surface that supports the accurate installation of overlying roofing materials. It’s a top choice in regions with extreme temperatures and harsh winters.

3. Roof Underlayment Problems Often Start With Poor Installation

Many things can cause a roof’s underlayment to fail, requiring roof repair or even full replacement. However, many of the most common causes can be attributed to poor or incorrect installation.

Damp Underlayment

Even a light coating of morning dew can make roof underlayment less than ideal for roof installation. Applying shingles over wet underlayment can inhibit adhesion and set the stage for early shingle failure and future roof leaks.

Insufficient Ventilation

Choosing the right underlayment type for every application is essential. While asphalt-saturated felt is a safe and economical choice for some homes, it can cause serious problems on others. For roofers, there’s a delicate balance between ensuring that roofs are watertight and that they have adequate ventilation. With insufficient attic ventilation and underlayment that lacks breathability, both the underlayment itself and the overlying roofing materials could fail.

Careless Workmanship

Having too much foot traffic on your roof when its underlayment is being installed can lead to ridges, bumps, wrinkles, rips, and other structural damage.

Insufficient Overlap

All underlayment types should overlap by several inches. This limits the risk of gaps that let moisture in even in the event of heavy foot traffic during installation. The applicable Dallas building codes set the minimum standards for overlap according to individual roof slopes, underlayment types, and roofing materials.

4. Quality Underlayment Protects Rough Framing

When shingles or tiles fail, underlayment keeps the rough framing of homes protected until homeowners schedule the necessary roof replacements or repairs. Failing to address underlayment problems can lead to warped and rotted wood, sagging roof sections, and other serious structural harm.

5. Flashing Problems Can Affect Roof Underlayment

Flashings are thin, flexible sheets of metal that roofers apply in moisture-vulnerable areas. You’ll find flashings around all roofing protrusions, at your roof’s eaves, and along your roof’s valleys. These are also the same locations where roofers apply ice and water barriers just above roof underlayment. If your roof has ripped or loose flashings or separation at its valleys, the nearby underlayment is poised to fail.

6. Damaged Roof Protrusions Can Cause Underlayment Problems, Too

It’s important to take good care of the protrusions that flashing protects. These include your skylights, exhaust vents, and chimneys. When these features are offset, cracked, poorly installed, or have other issues, your roof can sustain damage at all levels.

7. You Can Detect Underlayment Problems Early On

Although roof underlayment lies beneath your shingles or tiles, there are ways to detect underlayment problems without removing these things. Common signs of damaged or failing underlayment include:

  • Water stains on interior walls and ceilings
  • Warped or discolored siding
  • Buckling or curling shingles
  • Light entering the attic
  • Recurring problems with rooftop pests or mold

However, the best way to catch and correct underlayment problems before they affect other roofing elements or spiral out of control is by scheduling regular roof inspections.

We’ve proudly served the Dallas-Fort Worth Metroplex since 2004. With extensive experience in the roofing industry, we offer expert roof inspection, installation, maintenance, and repair services. We install gutter guards and provide gutter cleaning. Our company also installs solar panel systems.

If you need a new roof or help verifying and protecting the integrity of your exiting one, get in touch with KPost Company now.

FAQs

It is a small share of the total, which is why upgrading it is usually the cheapest performance decision in a roofing project. Labor, tear-off, disposal, and the shingles themselves carry most of the cost, and the difference between felt and a quality synthetic across an entire roof is modest by comparison. That ratio is worth knowing, because underlayment is often where a low bid quietly saves money.

For a short window, yes. A roof left dried in with underlayment and no covering will shed rain for a limited period, which is what allows a crew to tear off one day and finish the next. It is not a season-long solution. UV exposure degrades the material, wind works at the fasteners, and the exposure limit is set by the manufacturer rather than by how the roof looks. After storm damage, a tarp over the affected area is the safer bridge until the repair happens.

Often yes, because those assemblies run hotter and last longer. Metal panels transfer a great deal of heat into the layer beneath them, so high temperature rated underlayment is specified to keep the material from softening or losing adhesion. Tile roofs create a different problem, since the tile can last 50 years while standard underlayment cannot, which is why the underlayment under tile is the component that eventually forces the work. Our clay and concrete tile roofing team specifies underlayment to the life of the tile rather than to the life of a shingle.

Three places tell you. The original invoice or the manufacturer warranty document usually names the product. The attic side sometimes shows the underside of the deck and any staining that suggests a failure. Beyond that, lifting a small area at an inconspicuous spot shows it directly. If you are buying a house, ask for the roofing paperwork rather than assuming, since underlayment is not visible in an inspection photograph.

It can be repaired in place. The covering above the affected area is removed, the failed underlayment is cut out and replaced with an overlap into the sound material, and the covering goes back on. That works well for a defined area such as a valley or the section around a penetration. Where the failure is spread across the roof, or where it stems from the wrong product being used to begin with, replacing the covering is usually the more economical answer.
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