Ideal protection for asphalt shingles
As the protective layer between the shingles and the roof deck, roof underlayment provides essential defense against moisture, wind, and other environmental factors that can damage your home. But what is the best roof underlayment for asphalt shingles? Learn about the top three options to consider each type's cost, longevity, and effectiveness.
| Types of Underlayment | Cost Per Square |
|---|---|
| Asphalt-saturated felt | $5–$55 |
| Synthetic | $18–$60 |
| Rubberized asphalt | $50–$75 |
As the name suggests, asphalt-saturated felt consists of a base layer of organic felt material saturated with asphalt to create a barrier that helps shield the roof deck from water. Also known as tar paper, it’s available in 15- and 30-pound weights and is a popular and cost-effective option.
The price per square varies widely, averaging between $5 and $55. When properly maintained, asphalt-saturated felt can last 20 to 30 years.
| Pros | Cons |
|---|---|
| Cost-effective | Less durable |
| Readily available | May absorb moisture |
| Straightforward installation | Heavy and bulky |
| Fire resistant | Short life span |
Best for:
Homeowners seeking cost-effective roofing options
Areas with mild or moderate weather conditions
DIY roofing projects
Synthetic roof underlayment is a modern alternative to felt and is made from high-strength materials like polypropylene or polyethylene. It provides a durable and lightweight layer of protection that resists tearing, moisture, and UV exposure. Due to its lightweight nature, synthetic underlayment is easy to handle and install, and its non-slip surface can enhance safety during installation.
Synthetic roof underlayment cost per square ranges between $18 and $60 and can last 25 to 50 years. The versatility of this material also makes it one of the best underlayment for metal roofs.
| Pros | Cons |
|---|---|
| Easy and safe installation | High cost |
| Durable | Limited breathability |
| Moisture protection | Requires special fasteners |
| Lightweight | Not biodegradable |
Best for:
Areas with severe weather conditions
Homeowners seeking safety-conscious projects
Roofs with extended exposure to underlayment
Rubberized asphalt underlayment is best for asphalt shingle roofs in areas prone to extreme weather. The material is made from a combination of asphalt and rubber polymers, which gives it excellent waterproofing and the ability to self-seal around nails and fasteners. This type of underlayment is ideal for areas vulnerable to leaks, such as valleys, eaves, and around roof penetrations, and is particularly effective in preventing ice dams and water infiltration.
It costs between $50 and $75 per square. However, with a life span of up to 50 years, rubberized asphalt proves durable and is worth the higher cost for many.
| Pros | Cons |
|---|---|
| Excellent waterproofing | High cost |
| Ice dam protection | Challenging installation |
| Durable | Difficult to remove |
| Strong adhesion | Not suitable for all roofs |
Best for:
Cold climates and high moisture areas
Complex roof designs
Homeowners seeking long-term durability
Choosing a roof underlayment for your asphalt shingles requires looking at your specific needs as well as local conditions. Below are key factors to consider as you make your decision.
Climate: Rubberized asphalt is ideal for cold or wet areas prone to ice dams, while synthetic materials perform well in regions with high winds or prolonged sun exposure due to their tear resistance and UV stability. Felt would be a better option for those living in areas with moderate climate conditions.
Moisture resistance: In regions prone to heavy rain, snow, or ice dams, opt for underlayments with superior moisture protection. Rubberized asphalt provides excellent waterproofing and self-sealing around nails, which prevents leaks and water damage.
Budget: Your budget will affect the choice between more economical options like asphalt-saturated felt and higher-end materials like synthetic or rubberized asphalt underlayments. While felt is less expensive, synthetic and rubberized asphalt offer better long-term value due to their durability and performance benefits.
Durability: Consider the expected life span of your roof when choosing underlayment. Synthetic and rubberized asphalt underlayments offer enhanced durability and longer life spans, lasting up to 50 years. These materials are suitable for long-term installations while felt, with a maximum lifespan of 30 years, is best for shorter-term or lower-cost projects.
Installation: Consider the weight and flexibility of the underlayment, which affect ease of installation and handling. Lightweight materials like synthetic underlayments are easier to carry, cut, and install, potentially reducing labor costs and time on the job site. If there will be a delay between underlayment installation and shingle placement, you'll need to know how long can roof underlayment be exposed. Choose materials with good UV resistance, like synthetic underlayments.
Building codes and regulations: Ensure your chosen underlayment complies with local building codes, which may have specific requirements regarding fire resistance, moisture protection, and material type. Non-compliance can result in fines or costly modifications. Roof underlayment replacement costs range between $1,100 and $4,200.
Working on a roof is a job best left to a professional. However, if you have the necessary skills and experience, both felt and synthetic roof underlayment can be DIY-friendly. Asphalt-saturated felt is the most DIY-friendly option because it's straightforward to install, readily available, and requires minimal specialized tools. The material is easy to cut, lay down, and secure with nails or staples, making it a suitable choice for homeowners with advanced roofing DIY skills and tools. Synthetic underlayment can also be manageable for DIYers, as it's lightweight and easy to handle, but it may require more careful handling to avoid damage during installation.
Rubberized asphalt underlayment is less suited for DIY installation due to its self-adhering properties and the need for precise placement to avoid wrinkles and adhesion problems. This material is more challenging to work with, particularly in hot temperatures, and mistakes can be costly to fix since it bonds tightly to the roof deck. Given the high cost, you want to avoid mistakes by hiring a local roof insulation professional or a roofer near you. Knowing how to choose a roofer ensures the job is done well.
