A Comprehensive Comparison of Steep Slope Roofing Underlayments in Michigan Quality Cost and Code Requirements
- rbeisel005
- Feb 10
- 5 min read
Choosing the right roof underlayment is a critical step in any roof replacement or new roofing project, especially for steep slope roofing common in Michigan. The underlayment acts as a protective barrier beneath the shingles or tiles, shielding your home from water infiltration, ice dams, and wind-driven rain. With several options available—felt paper, low-grade synthetic underlayment, high-grade synthetic underlayment, ice and water shield, and high-grade self-adhering underlayment—it can be challenging to decide which material offers the best balance of cost, quality, and compliance with Michigan’s roofing building code.
This article breaks down the key differences between these underlayments, compares their costs and durability, and explains the current building code requirements in Michigan. By the end, you will have a clear understanding of which underlayment suits your roofing needs and budget.
Types of Steep Slope Roofing Underlayments
Felt Paper (Tar Paper)
Felt paper, often called tar paper, is the traditional roofing underlayment. It is made from organic or fiberglass mats saturated with asphalt. Felt paper comes in two common weights: 15-pound and 30-pound.
Advantages
- Affordable and widely available
- Easy to install
- Provides basic moisture protection
Disadvantages
- Prone to tearing and wrinkling in windy conditions
- Absorbs water, which can reduce effectiveness
- Shorter lifespan compared to synthetic options
Felt paper remains popular for budget-conscious homeowners but may not offer the best protection in Michigan’s harsh winters.
Low-Grade Synthetic Underlayment
Low-grade synthetic underlayment is made from polypropylene or polyethylene woven fabrics. It is lighter and stronger than felt paper.
Advantages
- More tear-resistant than felt paper
- Lightweight and easier to handle
- Better water resistance
Disadvantages
- Lower slip resistance, which can be a safety concern on steep slopes
- May degrade faster under UV exposure
- Typically less expensive than high-grade synthetics but still pricier than felt
This type offers a middle ground between cost and performance but may not be ideal for long-term durability.
High-Grade Synthetic Underlayment
High-grade synthetic underlayment uses advanced polymers and often features a slip-resistant surface. It is designed for durability and superior moisture protection.
Advantages
- Excellent tear and puncture resistance
- High slip resistance improves safety during installation
- UV resistant for longer exposure times
- Lightweight and easy to install
Disadvantages
- Higher upfront cost compared to felt and low-grade synthetics
For homeowners seeking long-lasting protection and ease of installation, this option is a strong choice.
Ice and Water Shield
Ice and water shield is a self-adhering membrane made from rubberized asphalt with a sticky backing. It is designed to seal around nails and prevent water intrusion from ice dams and wind-driven rain.
Advantages
- Superior waterproofing, especially in vulnerable areas like eaves and valleys
- Adheres directly to the roof deck, preventing leaks
- Provides an extra layer of protection against ice dams
Disadvantages
- More expensive than traditional underlayments
- Installation requires care to avoid wrinkles and bubbles
- Typically used in specific areas rather than the entire roof
Ice and water shield is often required by building codes in Michigan for certain roof sections prone to ice damming.
High-Grade Self-Adhering Underlayment
This underlayment combines the benefits of synthetic materials with self-adhering properties similar to ice and water shield. It offers full roof coverage with a sticky backing.
Advantages
- Excellent waterproofing across the entire roof deck
- High durability and tear resistance
- Simplifies installation by reducing the need for fasteners
- Ideal for steep slope roofing where water infiltration risk is high
Disadvantages
- Highest cost among underlayment options
- Requires careful surface preparation for adhesion
This premium option is suited for homeowners who want the best protection and are willing to invest upfront.
Cost Comparison of Roofing Underlayments
| Underlayment Type | Approximate Cost per Square (100 sq ft) | Durability (Years) | Notes |
|--------------------------------|-----------------------------------------|--------------------|----------------------------------------|
| Felt Paper (15 lb) | $15 - $25 | 5 - 10 | Cheapest option, basic protection |
| Low-Grade Synthetic | $30 - $50 | 10 - 15 | Better durability, moderate cost |
| High-Grade Synthetic | $50 - $70 | 15 - 25 | Long-lasting, safer installation |
| Ice and Water Shield (Rubberized) | $100 - $150 | 20+ | Used in critical areas, excellent seal |
| High-Grade Self-Adhering | $120 - $180 | 20+ | Full roof coverage, premium protection |
Costs vary based on brand, roof size, and contractor pricing. While felt paper is the most affordable, synthetic underlayments offer better value over time due to longer lifespan and improved protection.
Quality Comparison and Performance
| Feature | Felt Paper | Low-Grade Synthetic | High-Grade Synthetic | Ice and Water Shield | High-Grade Self-Adhering |
|------------------------------|------------|---------------------|---------------------|---------------------|-------------------------|
| Water Resistance | Moderate | Good | Excellent | Excellent | Excellent |
| Tear Resistance | Low | Moderate | High | High | High |
| UV Resistance | Poor | Moderate | High | High | High |
| Slip Resistance | Moderate | Low | High | High | High |
| Installation Ease | Easy | Easy | Easy | Moderate | Moderate |
| Cost Efficiency | High | Moderate | Moderate | Low | Low |
High-grade synthetic underlayments and self-adhering membranes provide the best overall protection, especially in Michigan’s climate where ice dams and heavy snow are common. Felt paper may be suitable for mild climates but offers limited protection against water intrusion and damage.
Michigan Roofing Building Code Requirements for Underlayment
Michigan’s building code follows the International Residential Code (IRC) with specific amendments for roofing underlayments. Key points include:
Minimum Underlayment
- At least one layer of underlayment is required beneath steep slope roofing materials.
- Felt paper or synthetic underlayment is acceptable.
Ice and Water Shield Requirements
- Ice and water shield or a self-adhering membrane must be installed in areas vulnerable to ice dams.
- This includes eaves, valleys, around chimneys, skylights, and roof penetrations.
- The minimum coverage is typically 24 inches inside the exterior wall line.
Underlayment Overlaps
- Overlaps must be at least 2 inches horizontally and 4 inches vertically to prevent water infiltration.
Fastening
- Underlayment must be fastened securely with roofing nails or staples, except for self-adhering membranes.
Manufacturer Instructions
- Installation must follow the underlayment manufacturer’s guidelines to maintain warranty and code compliance.
These requirements ensure that roofing systems in Michigan can withstand the region’s weather challenges, including heavy snow, ice buildup, and wind-driven rain.
Choosing the Right Underlayment for Your Michigan Home
When selecting roof underlayment, consider these factors:
Climate and Weather
Michigan’s cold winters and frequent freeze-thaw cycles increase the risk of ice dams. Ice and water shield or self-adhering membranes are essential in vulnerable areas.
Roof Slope and Material
Steep slope roofing requires underlayments with good slip resistance and durability. High-grade synthetic options provide safer installation and longer life.
Budget
While felt paper is affordable, its shorter lifespan may lead to higher costs over time. Investing in high-grade synthetic underlayment can save money on repairs and replacements.
Building Code Compliance
Follow Michigan’s roofing building code to avoid inspection issues and ensure your roof performs well.
Installation Quality
Proper installation is as important as material choice. Hire experienced roofing contractors familiar with local codes and best practices.
Summary
Selecting the right roof underlayment is vital for protecting your home from Michigan’s challenging weather. Felt paper offers a low-cost option but lacks durability and water resistance. Low-grade synthetic underlayment improves on felt but may fall short in safety and longevity. High-grade synthetic underlayment balances cost and performance, providing excellent protection and ease of installation. Ice and water shield is critical for preventing leaks in vulnerable areas, while high-grade self-adhering underlayment offers premium, full-roof protection at a higher price.