When it comes to roofing, most people only know of asphalt shingles and metal roofs. However, roofing underlayment is another technique that has recently gained popularity. There are various roofing underlayment, but synthetic roof underlayment is the most common.
This blog post will discuss the pros and cons of synthetic roof underlayment and some of the problems that can occur when using this product. We shall also highlight types of synthetic roof underlayment that are available today.
What Is Roof Underlayment?
Roofing underlayment is a layer made of various materials installed under the shingles or metal roofing to provide an extra layer of protection. The underlayment is waterproof/water-resistant and acts as a barrier between the roofing material and the roof sheathing.
Underlayment is installed after the roof decking and protects against harsh elements, moisture, and leaking. In addition, the roof underlayment increases the roof’s stability and helps prevent wind damage.
Types of Roofing Underlayment
There are three commonly used roofing underlayments: synthetic, felt, and self-adhered. Each type has its benefits and drawbacks. Here is a short description of each underlayment type:
Synthetic Roofing Underlayment
Synthetic roof underlayment is an artificial product that protects the roof deck from weather damage. It is usually made from laminated Polypropylene, polyethylene plastic, polyester, and fiberglass- which are durable and waterproof materials. Synthetic roof underlayment is available in different thicknesses, but the most common thicknesses are 30, 40, and 50 mils.
Synthetic materials are generally lighter and thinner than felt paper. They provide better tear resistance, UV resistance, and puncture resistance. Synthetic underlayment can last up to 20 years, longer than traditional asphalt felt paper.
Synthetic roof underlayment is also easier to install. It is available in rolls that are easy to handle and can be installed with staples, nails, or adhesive. They also require no special equipment for installation.
However, synthetic underlayment are more expensive than felt paper and can be more challenging to repair if damaged. In addition, synthetic underlayment have restrictions in some building codes.
Asphalt Felt Roofing Underlayment
Felt underlayment is one of the oldest roof underlayments used in the roofing system. Felt is made from organic materials like wood pulp combined with asphalt to create a mat. This mat is rolled out and attached to the roof decking with nails or other fasteners.
Felt underlayment comes in two types- No.15 and No.30. No.30 felt is composed of a heavier base mat with a thicker asphalt coating and is used in areas prone to high winds.
No.15 felt is composed of a lighter base mat with a thinner asphalt coating and is typically used on sloped roofs where leaks are less likely to occur.
One problem is that the organic materials in the felt can rot when they get wet. This can cause the underlayment to break down and no longer be effective at protecting the roof decking from water damage. In addition, UV exposure can cause the asphalt to break down, making the underlayment less effective at keeping water out.
Self-Adhered Roofing Underlayment
Think of a sticky tape, and you can get a pretty good idea of how self-adhered roofing underlayment works. The membrane is coated with an aggressive adhesive that bonds to the roof deck when pressed into place. No fasteners or mechanical attachments are required, making this underlayment quick and easy to install.
This underlayment comes in two layers. The top layer (60 mils) provides excellent puncture, tear, and UV resistance, while the bottom layer (55 mils) forms a solid bond to the roof deck.
One significant advantage of self-adhered roofing underlayment is that it creates a continuous barrier against water and air. This is because the adhesive bond between the membrane and the roof deck is solid, eliminating the possibility of gaps or leaks.
Self-adhered roofing underlays are also very lightweight, making them easy to transport and handle during installation.
Types of Synthetics Roof Underlayments
There are various types of synthetic roofing underlayments available. Some include;
Polyester
Polyester is a type of synthetic material made from synthetic fiber. It’s lightweight and easy to install. In addition, polyester is breathable, which helps keep your home cooler in the summer and warmer in the winter. However, polyester is not as strong as some other types of synthetic roofing underlayments.
Polypropylene
Polypropylene is another type of synthetic roofing underlayment created using recycled materials. It is also lightweight and easy to install. In addition, Polypropylene is moisture resistant and does not rot or mildew. However, like polyester, Polypropylene is susceptible to damage from harsh elements.
Fiberglass
Fiberglass is a type of synthetic roofing underlayment that is made from glass fibers. It is lightweight and easy to install. Fiberglass is also moisture resistant and does not rot or mildew.
However, fiberglass can be damaged by sun ultraviolet (UV) rays and is not as strong as other synthetic roofing underlayment.
Polyethylene
Polyethylene is made from plastic and is the most common type of synthetic roofing underlayment. It is lightweight and easy to install. Polyethylene is also moisture resistant and does not rot or mildew. However, the Polyethylene face gets damaged by the sun’s ultraviolet (UV) rays.
Benefits of Synthetic Roof Underlayment
We created a list of benefits of synthetic roof underlayment to help you make an informed decision about whether or not to use it on your property.
Water-Resistant
The ability to resist water is one of the primary benefits of synthetic roof underlayment. This material is often used in areas that experience a lot of moisture and precipitation. It is also an underlayment for shingles because it can help prevent leaks.
Lightweight
Most roofing contractors prefer Synthetic roof underlayment since it’s much lighter than traditional felt paper. This makes it easier to work with and less likely to cause damage to your roofing during installation.
Easy to Install
The installation of synthetic roof underlayment is quick and easy. It can be rolled out over the entire roof surface and then fastened with nails or staples. This material is also less likely to tear than traditional felt paper.
Tough and Durable
Synthetic roof underlayments are made of materials that are tough and durable. They are designed to withstand the elements and last for many years.
This type of material is often used in commercial applications where it needs to be able to stand up to heavy traffic and wear and tear. They are also ideal for areas that experience a lot of extreme weather conditions.
Longevity
A roofing project is a costly investment. You want to ensure that the products you use will last for many years. Synthetic roof underlayments are designed for longevity and can resist UV rays and extreme temperatures.
Most synthetic roof underlayments will last 20 years or more with proper care and maintenance. They will not rot or deteriorate like other materials, making them an excellent choice for roofing projects.
Pliable and resilient
Synthetic roof underlayment is very flexible, which allows it to conform to the contours of your roof. This underlayment is less likely to crack or break when exposed to extreme temperatures.
Protects Against UV Rays
Synthetic roof underlayment can help to protect your home from the damaging effects of UV rays. This material is often used in areas that experience a lot of sun exposure. It can help reflect the heat away from your home and keep it more relaxed during summer.
Safe
Many homeowners are concerned about the safety of synthetic roofing materials. However, synthetic underlayment is very safe to use. It does not contain any asbestos fibers or other harmful chemicals.
Problems with Synthetic Roof Underlayment
Below are some drawbacks associated with synthetic roof underlayment;
1. High cost
High cost is the biggest disadvantage of synthetic roofing underlayment. The initial investment in synthetic underlayment is significantly higher compared to its counterparts. The high-cost limits homeowners who operate under a tight budget. However, this cost is justifiable, given the benefits that come with it.
2. Complicated Installation Process
Synthetic roofing underlayment is complicated to install and requires the expertise of a professional roofer. The material is also harder to work with because it doesn’t conform to irregular surfaces as quickly as felt paper. This makes the installation process more time-consuming and expensive.
3. Increased risk of Leaks
Although synthetic roofing underlayment has higher water resistance, it’s not entirely waterproof. If installed incorrectly, it can lead to leaks. Also, if there are holes or punctures in the synthetic underlayment, water can seep through and cause damage to your roof.
Unsure Warranties and Exposure Limits
Most synthetic roofing underlayments manufacturers list a time limit of between two to 30 months for exposure to weather. This means that the underlayment should be covered with roofing material within this time frame, or it will start to degrade.
However, this period is not scientifically proven, and there is no test to determine if the underlayment has reached its expiration date. This leaves many homeowners in the dark about when their synthetic underlayment will start to degrade and whether or not the warranty still covers it during this period.
To avoid such problems, we recommend installing your synthetic underlayment as soon as possible after receiving it. This will ensure that you don’t have to worry about the expiration date and whether or not the warranty still covers the product.
5. Longevity
While synthetic roofing underlayment can last up to 20 years, there have been reports of problems arising in only a few years. In some cases, the products have been known to degrade in UV light, become brittle in cold weather, or degrade when exposed to certain chemicals.
6. Restricted in Some Building Codes
Building codes in some areas do not allow synthetic roofing underlayment. This is because it doesn’t provide the same level of fire protection as felt paper.
Additionally, synthetic underlayment materials are not as biodegradable as their natural counterparts, which can be a problem if disposed of in a landfill. If your area has strict building codes, you may not be able to use synthetic underlayment on your roof.
7. Mil Thickness
The thickness of synthetic roofing underlayment is usually measured in mils. However, most brands range from 30 to 60 mils, with the higher number indicating a thicker product.
Unfortunately, most brands have been targeting customers with thick synthetic underlayments of poor quality. A 30 or 40-mil synthetic underlayment from a reputable manufacturer will outperform a 60-mil product from a lesser-known brand.
To ensure you get the best synthetic underlayment, we recommend you look at the weight and tear resistance of the underlayment before making a purchase.
8. Moisture is Trapped in the Attic
Most synthetic underlayments have a permeance rating of 0.1 perms or less. This means that the underlayment does not allow moisture to pass through, leading to condensation and trapped moisture in the attic.
This can be a severe problem if you live in a hot and humid climate, as it creates the perfect environment for mold and mildew to thrive.
To avoid this problem, ensure your attic is well ventilated to allow any trapped moisture escape. You should also consider using an airtight vapor barrier over the synthetic underlayment to prevent moisture from being trapped in the first place.
How to Choose the Right Roof Underlayment
While selecting an underlayment roofing system can be challenging, it doesn’t have to be. With the proper research and due diligence, you can find a plan that will work well for your home or commercial building.
Here are a few factors to keep in mind when choosing an underlayment roofing system:
Climate
The climate is one of the most important factors when choosing an underlayment for roof installation. Different types of underlayment roofing systems are better suited for different environments.
For example, if you live in an area with a lot of rainfall, you’ll want to ensure that the underlayment you select will handle the additional moisture.
Similarly, if you live in an area with extreme temperatures, you’ll want to ensure that the system can withstand both the heat and the cold.
Building Use
The building you’re using the underlayment roofing system for will also play a role in your decision-making process. If you’re using the underlayment for a commercial building, choosing a system that can handle the increased foot traffic is essential.
On the other hand, if you’re using the system for a residential home, you may get away with a less durable (and less expensive) underlayment.
Budget
Of course, budget is always a consideration when making any major purchase. Luckily, various underlayment roofing systems are available at different price points. Finding a design that fits your needs and your budget is crucial.
The Type of Roofing
Most underlayment manufacturers do not recommend the type of roofing that you should use with their products. However, using a breathable roofing system such as asphalt shingles would be beneficial if you have a vapor-permeable underlayment and live in a hot and humid climate. This will allow the moisture to escape from your home, preventing mold or mildew growth.
On the other hand, if you have a non-permeable underlayment, you can use any roofing system. However, ensuring that the nails used to secure the roofing are long enough to penetrate through the underlayment and into the decking beneath is essential. However, ensure you seek advice from a roofing contractor before purchasing.
Conclusion
While synthetic roof underlayment has many benefits, there are also some potential problems that homeowners should be aware of. These include the possibility of leaks, the need for regular maintenance, and the case of damage from high winds. Therefore, homeowners considering synthetic roof underlayment should weigh the pros and cons carefully before deciding.