When most homeowners think about their roof, asphalt shingles or metal roofs come to mind. But hidden beneath those outer layers lies a critical component that plays a vital role in protecting your home: roofing underlayment.
Often overlooked, roofing underlayment is the extra layer that helps your roof breathe, provides a moisture barrier, and offers additional protection against the elements. If you live in a region like Winnipeg, where harsh weather and extreme freeze-thaw cycles are the norm, understanding and choosing the right roofing underlayment is essential to avoid costly repairs and water damage.
A roof underlayment is a protective membrane installed directly onto the roof deck, beneath your shingles or metal panels. Think of it as the unsung hero of your roofing system—essential, yet mostly invisible.
Why is it often overlooked? Well, since it’s hidden from sight, most homeowners simply aren’t aware of its importance. But in climates like Winnipeg’s, where wind driven rain, ice dams, and high winds are a constant threat, the underlayment may be the one thing standing between a watertight roof and a major leak.
What Is Roofing Underlayment?
Roofing underlayment is a water resistant underlayment layer installed between your roof deck (typically made of plywood or OSB) and the shingles or metal roofing material. Its main job? To act as a secondary moisture barrier, preventing water penetration if your shingles loose or become damaged.
There are several types of underlayment, including:
- Felt underlayment (also called tar paper or asphalt saturated felt paper)
- Synthetic roofing underlayment
- Rubberized asphalt underlayment
Historically, felt paper made from natural plant fibers and soaked in asphalt was the go-to. But with new technologies, synthetic underlayment has become increasingly popular due to its water resistance, durability, extra protection and UV exposure resistance.
The Role of Underlayment in Your Roofing System
Your roof’s main job is to keep the elements out—and that’s exactly what roofing underlayment protects against. Here’s how it helps:
- Acts as a secondary barrier: If shingles are damaged or lifted, underlayment keeps water from seeping in, preventing water damage.
- Protects against wind-driven rain and ice dams: Winnipeg winters bring snow, sleet, and ice dams—all of which can trap water under shingles.
- Prevents wood rot and structural damage: Keeping water off your roof deck helps stop mould, mildew, and fungal growth.
- Extends the lifespan of your roof: A well-installed underlayment means fewer leaks and less maintenance over time.
Types of Roofing Underlayment
Let’s break down the three main options when choosing roofing underlayment for your home.
a. Asphalt-Saturated Felt (Traditional Roofing Felt Underlayment)
- Known as felt underlayment or asphalt saturated felt
- Made from natural plant fibres soaked in asphalt
- Affordable and easy to install
Pros and Cons:
- ✅ Cost-effective
- ✅ Decent water resistance
- ❌ Heavier and more prone to tearing
- ❌ Shorter lifespan compared to modern options
Still a good choice for budget-friendly roofing projects or as an extra layer under certain conditions.
b. Synthetic Underlayment
- Lightweight, durable, and popular in modern roofing
- Made from polypropylene or polyethylene materials
Key benefits:
- ✅ Superior water resistance
- ✅ Higher fire ratings
- ✅ Better for steeply sloped roofs
- ✅ Resists UV exposure, meaning it can be left exposed for longer
Synthetic roofing underlayment is often the top pick for professional roofers, especially in areas with severe weather conditions.
c. Rubberized Asphalt Underlayment
- The premium choice in waterproof underlayments
- Often comes with a self-adhesive backing
Why choose it?
- ✅ Excellent for roof valleys, edges, and around vents—areas prone to water penetration
- ✅ Best for preventing leaks in flat roofs and low-slope areas
- ❌ Higher cost, but offers superior protection
If you’re planning a roof replacement and want maximum peace of mind, this could be your best bet.
Roofing Underlayment and Manitoba Weather
Living in Manitoba means dealing with freeze-thaw cycles, snow dams, and heavy storms. This creates a unique set of challenges for your roofing system and shingle installation.
- Ice dams can form along the roof edge, backing water up under shingles
- Wind driven rain can lift shingles and force moisture underneath
- Constant moisture can lead to rot, mould, and leaks
Installing roofing underlayment and the right roofing material designed for cold climates—especially rubberized asphalt underlayment—adds essential waterproofing and extra protection.
Is Roofing Underlayment Necessary?
Yes—roofing underlayment is necessary, even if your roof looks intact.
Here’s why:
- Local building codes in Canada require it on most residential roofs
- Insurance providers often mandate it for warranty coverage
- Misconceptions like “shingles alone are enough” can lead to moisture damage and expensive repairs
Proper underlayment is a vital component of a modern, compliant, and resilient roofing project.
How Underlayment Is Installed
While DIY-savvy homeowners might be tempted, installing roofing underlayment properly is a job for reputable roofing contractors.
- Installation Process: The underlayment is rolled out over the entire roof deck, secured with nails or adhesive, then overlapped for full coverage.
- Professional Touch: Correct placement—especially around roof penetrations, valleys, and eaves—is key to preventing leaks.
- At Above All Roofing & Exteriors, our expert team ensures precise underlayment placement on every job for long-lasting results.
Roofing Felt vs. Synthetic Underlayment: Which Is Better?
Here’s a quick comparison to help you decide.
| Feature | Asphalt Felt | Synthetic Underlayment |
|---|---|---|
| Durability | Moderate | High |
| Weight | Heavy | Lightweight |
| Water Resistance | Decent | Excellent |
| Cost | Lower | Mid-range to High |
| Installation Ease | Basic | Easier to handle |
For most modern roofs, especially steeper roofs, synthetic underlayment offers the best balance of waterproofing and ease of use.
Why Trust Above All for Roofing in Winnipeg
- Decades of local expertise with Winnipeg’s unique climate
- Every project uses high-quality underlayment, tailored to your roof type
- Trusted by homeowners for residential and commercial roofing
- We don’t just meet building codes—we aim to exceed them
We’re proud to help most homeowners get peace of mind from a strong, durable roof.
Final Thoughts: Protect What’s Under Your Roof
So, is roofing underlayment necessary? Absolutely. Whether you’re upgrading your current roof or planning a new roof installation, never skip this essential layer of protection.
From improving water resistance to extending the life of your roof, underlayment plays a huge role in keeping your home dry, safe, and secure.
💡 Thinking about a roofing project in Winnipeg? Let the experts at Above All Roofing & Exteriors help. Contact us today for a free roof inspection or estimate. Protect your home from leaks, strong winds, and moisture damage—starting from the bottom up.