Roofing Underlayment Guide

What Is Roofing Underlayment?

Most homeowners focus on shingles when thinking about a roof, but one of the most important parts of the roofing system is actually hidden underneath them.

Roofing underlayment is the protective layer installed between the roof decking and the exterior roofing material.

It serves as a secondary moisture barrier that helps protect the home from:

• Water intrusion

• Wind-driven rain

• Ice dams

• Snow melt

• Condensation

In Colorado, underlayment plays a critical role because roofs are constantly exposed to severe weather conditions.

Why Roofing Underlayment Matters in Colorado

Colorado roofs face unique environmental challenges, including:

• Hailstorms

• Heavy snow

• Freeze-thaw cycles

• High winds

• Intense UV exposure

• Rapid temperature swings

If shingles become damaged during a storm, the underlayment often becomes the temporary barrier protecting the home from leaks.

A quality underlayment system can help reduce the risk of:

• Moisture damage

• Rotting decking

• Interior leaks

• Mold growth

• Premature roof failure

The Main Types of Roofing Underlayment

There are several common types of underlayment used in residential roofing systems.

Each offers different levels of durability, water resistance, and performance.

Asphalt-Saturated Felt Underlayment

Often called “felt paper” or “tar paper,” this is one of the oldest roofing underlayment materials still used today.

Advantages of Felt Underlayment

• More affordable upfront

• Widely available

• Familiar to many contractors

• Provides basic moisture protection

Potential Drawbacks

• Heavier material

• Tears more easily

• Can absorb moisture

• Less durable during installation exposure

• May wrinkle when wet

While still used on some projects, many modern roofing systems now use synthetic underlayment instead.

Synthetic Roofing Underlayment

Synthetic underlayment has become increasingly popular because of its durability and weather resistance.

These products are typically made from engineered polymers designed for roofing applications.

Advantages of Synthetic Underlayment

• Lightweight material

• Strong tear resistance

• Better moisture protection

• Improved durability during installation

• Better UV resistance during temporary exposure

• Often safer for installers to walk on

Why Many Colorado Roofers Prefer Synthetic Materials

Because Colorado weather can change quickly, synthetic underlayment often performs better during:

• High winds

• Sudden rainstorms

• Snow exposure

• Temperature swings

Many homeowners also choose synthetic systems for their improved long-term durability.

Ice & Water Shield: Extra Protection in Vulnerable Areas

Ice and water shield is a specialized waterproof membrane used in areas more vulnerable to leaks.

Unlike standard underlayment, this material seals more tightly around nails and fasteners.

Common Areas Where Ice & Water Shield Is Installed

• Roof eaves

• Valleys

• Around chimneys

• Skylights

• Roof penetrations

• Low-slope sections

Why It Matters in Colorado

Colorado’s freeze-thaw cycles create ideal conditions for:

• Ice dams

• Snow melt backup

• Water intrusion

Ice and water shield provides an additional layer of protection in these higher-risk areas.

Underlayment Is Not All Installed the Same Way

Even high-quality underlayment can fail if installed improperly.

Installation mistakes may include:

• Incorrect overlap

• Improper fastening

• Poor sealing around penetrations

• Wrinkled installation

• Inadequate coverage

Proper installation becomes especially important during Colorado windstorms, where poorly secured materials may become vulnerable to uplift.

Roofing Material Affects Underlayment Choices

Different roofing systems may require different underlayment types.

Asphalt Shingles

Often paired with synthetic or felt underlayment.

Metal Roofing

May require high-temperature underlayment depending on the system design.

Tile Roofing

Sometimes uses heavier-duty underlayment systems because of the roof weight and lifespan expectations.

Low-Slope Roofs

May require specialized waterproof membranes for added protection.

The best underlayment depends on both the roofing material and local climate conditions.

Underlayment Helps Protect During Storm Damage

After severe hail or wind storms, shingles may become compromised before leaks appear inside the home.

In many cases, underlayment becomes the temporary defense layer protecting the roof decking from moisture intrusion.

A stronger underlayment system can sometimes help reduce immediate leak risks after storm events.

Can Old Underlayment Be Reused?

In most full roof replacements, old underlayment is removed and replaced.

Reusing older materials is generally not recommended because hidden wear or moisture damage may already exist beneath the surface.

A new roof system performs best when all protective layers work together properly.

Questions to Ask About Roofing Underlayment

Before starting a roofing project, homeowners should ask:

• What type of underlayment is being installed?

• Is synthetic underlayment included?

• Where will ice and water shield be applied?

• Does the system meet local code requirements?

• Is the underlayment compatible with the roofing material?

• How long can the underlayment remain exposed if weather delays occur?

These details can have a major impact on long-term roof performance.

A Roof Is More Than Just Shingles

While shingles get most of the attention, roofing underlayment plays a huge role in protecting homes from Colorado’s harsh weather conditions.

A properly installed underlayment system can help:

• Prevent leaks

• Protect roof decking

• Improve storm resistance

• Reduce moisture problems

• Extend roof lifespan

If you’re planning a roof replacement or have questions about your current roofing system, Colorado Front Range Roofing can help explain your options and recommend the best underlayment solution for your home.