best underlayment for metal roof

Best Underlayment for a Metal Roof for Homeowners

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As a homeowner, I recommend investing in the best underlayment for a metal roof. In fact, a house with no roof underlayment can be quite loud whenever it's raining, be unbearable warm in the summer, and be frosty throughout the winter season. This post will guide you in choosing the right underlayment for residential and commercial projects. Read on!

Why Do You Need Metal Roof Underlayment?

Roof underlayment is a type of water-resistant material or vapor barrier installed beneath the top roofing layer to provide extra protection against moisture intrusion and weather impacts. You can install it underneath any roofing material, usually directly into the roof sheathing or decking.

Though metal roofing doesn't require an extra layer to offer a waterproof surface or maintain its structural integrity, it still benefits a lot from the underlayment. Even with the metal roofing, water can still find its way through the cracks, crevices, or loose joints. But with the best underlayment for metal roofs, you won't have to worry about infiltration or condensation accumulation in your roof space.

When choosing a roof underlayment for metal roofs, ensure it matches the lifespan of your roofing. For instance, if you are installing a 30-year roof, you need an underlayment that will last that long. That said, underlayment is essential since it protects your roof system and your home.

Now that we understand the importance of installing roofing underlayment let's check out the best options to invest in.

1. Mfm Peel & Seal Self Stick Roof Underlayment, 50036

Sale
Mfm Building Product 50036 Mfm Peel & Seal Self Stick...
  • The product is manufactured in united states
  • Package Length: 7.0"
  • Package width: 7.0"
  • Package Height: 8.0"

Mfm Peel & Seal Stick Roof Underlayment is made of aluminum composite foil, cross-linked polymer, and rubberized asphalt, making it flexible and self-adhering. It's ideal for roofs that aren't easy to waterproof, including metal roofs, sunroofs, RVs, and mobile homes. Installation is easy; no glues, tapes, or fasteners are required.

I used this underlayment on my newly constructed house, and I don't regret buying it. The good thing is, besides using it on my metal roof, I also used it for gutter repair to act as a waterproofing barrier. So one roll was able to cover a large surface. Additionally, the underlayment didn't warp, buckle or crack during installation.

Pros:

  • Easy to install
  • Doesn't warp, buckle or crack during installation
  • Strong and durable
  • One roll can cover a large surface

Cons:

  • It is expensive

2. Tyvek Protec 4' x 250' Roof Underlayment, 120

Tyvek Protec 120 Roof Underlayment 4' x 250' - 1 Roll
  • Compatible with roofs with asphalt shingles, cedar shingles and...
  • Use for repair, re-roofing and new construction applications
  • Trusted quality and durability from DuPont Tyvek
  • The unique embossed pattern allows for better traction and grip...

Tyvek Protec 120 Underlayment has a unique embossed pattern that offers better traction and grip while walking on the roof during installation. It also features a slip-resistance coating that prevents it from sliding after installation. You can use it under metal roofs, asphalt shingle roofs, or cedar roofs. Additionally, the underlayment is perfect for applications from renovation to new construction.

The roofing underlayment is made from woven polyethylene, providing a water barrier layer that expels water and debris and withstands UV exposure. The protection offers greater peace of mind. Besides, it has a wrinkle-free surface for easier installation. Moreover, you will enjoy the additional benefits of lightweight durability.

Pros:

  • Perfect for applications from renovation to new construction
  • Easy to install
  • It acts as a water barrier
  • Can withstand UV exposure

Cons:

  • It is expensive

3. Tyvek Protec 4' x 250' Roof Underlayment, 200

Tyvek Protec 200 Roof Underlayment - 4' x 250' - 1 Roll
  • Excellent walkability
  • Easy to chalk; accepts and holds chalk marks for more visible...
  • Lays flat for a more uniform shingled surface
  • Preserves the roof deck during installation and provides an...
  • Trusted DuPont(TM) Tyvek quality and durability

Tyvek Protec 200 is a synthetic sheet underlayment featuring a unique embossed non-woven DuPont technology. You can use it under various roofing materials, including; metal roofing, asphalt shingle, cedar, tile, cladding, or slate with a slope of 2:12 or higher. Besides, the underlayment has industry-leading walk-ability and offers performance even under oppressive conditions.

This underlayment is perfect for new construction, sloped residential and commercial roofs, and re-roofing applications. It's easy to chalk since it usually accepts and retains chalk marks for more visible lines and a great finished product. Besides, the underlayment preserves the roofing deck during installation and adds additional protection against UV exposure and moisture.

Pros:

  • Easy to install
  • Has industry-leading walk-ability
  • Can withstand UV exposure
  • You can use it under various roofing materials

Cons:

  • It is expensive

4. ArmorLay 4' x 250' Synthetic Roof Underlayment, 25

ArmorLay 25 Synthetic Roof Underlayment 4' x 250'
  • 10 square roll covers 1,000 square feet
  • Meets performance characteristics ASTM D4869 and ASTM D226...
  • 60 Day exposure to UV
  • Slip resistant polymer applied to the bottom surface. Unique...
  • Won’t buckle, warp, or crack , Water resistant

If you are looking for the best underlayment for a metal roof that's easy to install, count on the ArmorLay 25 Roofing Underlayment. The underlayment is a 10-square roll that covers up to 1,000 square feet. Besides, you can use it under various roofing materials, including metal roofs, asphalt composite roof shingles, and steep slope roofs.

The roofing underlayment won't warp, buckle or crack during installation. On the other hand, this ArmorLay 25 Roof Underlayment has a slip-resistant slip-resistant polymer on the bottom surface and a unique textured fabric, which usually allows steep slope walk-ability.

Pros:

  • Extremely easy to install
  • It offers a large roof coverage
  • Allow steep slope walk-ability
  • You can use it under various roofing materials

Cons:

  • It is expensive

5. DuPont 42' x 286' Roof Protector Underlayment Roll

Sale
Roof Protector Underlayment Roll - 42" x 286'
  • Lightweight for easy handling and installation with 90 day UV...
  • Superior tear resistance compared to roofing felt for increased...
  • Ideal for for sloped (>= 2:12) commercial and residential roofs...

DuPont Roof Protector Underlayment has a high strength to weight ratio, making it easy to install. Besides, the roof underlayment has a four-layer design, providing excellent traction to the roof deck, great grip-ability for slip resistance, and strength to reduce tearing at the fastener spots. Conversely, you can use it for sloped residential and commercial roofs and roofing applications under metal cladding or asphalt roofs.

The underlayment is a 10-square roll; therefore, you can expect maximum roof coverage. On the other hand, there are fewer overlaps, fasteners, and seams, which helps reduce labor. In addition, the roof underlayment can withstand severe circumstances due to its superior durability and thermal stability.

Pros:

  • Easy to install
  • It offers a large roof coverage
  • You can use it for sloped residential and commercial roofs
  • It offers great gripability for slip resistance

Cons:

  • Some users complain of the underlayment shrinking in the sun.

Types of Underlayment for Metal Roofing system?

1. Felt Underlayment

Felt underlayment (tar paper, felt paper or asphalt saturated felt ) is the most common material for steeper-sloped metal roofing. It's made of natural fibers, including fiberglass, polyester base, wood cellulose, or synthetic fibers.

One of the main reasons homeowners prefer it is because it's the least expensive material option. It's also reliably water-resistant. We recommend using a double layer of 15# under metal roof panels or 30# felt underlayment.

Though it's a cheaper option, it has some drawbacks. One of them is that it can't handle high temperatures for extended periods. Also, it has a shorter life span, meaning you will need to replace it before your roof.

Pros

  • It comes at an affordable price.
  • It's water-resistant, preventing water from getting to the surface in case of leaks through the roofing structure.
  • It's available virtually anywhere.

Cons

  • Installation can be difficult since asphalt-based products will likely bend and wrinkle during installation.
  • Requires a slip sheet - This is a layer of construction paper usually installed beneath the roofing material to prevent the felt underlayment from sticking or damage that can happen when it comes into contact with metal panels. The slip sheet makes installation a bit costly.
  • It's not suitable for high-temperature environments.
  • It has a shorter lifespan.
  • The material raises concerns about fire resistance since it's made from petroleum, which is highly flammable.
  • It cannot be exposed for an extended period. It's prone to rips from severe winds.

2. Synthetic Sheet Underlayment

Synthetic underlayment is quickly gaining popularity in the metal roofing industry as a superior, more advanced alternative for felt type. It's a roofing accessory that combines polyethylene (or polypropylene) with a polymer to form a strong protective barrier between the underlayment and the metal roof deck.

Synthetic underlayment has a longer lifespan than felt type since the thermoplastic polymers are resistant to various types of damage, making them more durable. Also, it performs well in hotter temperatures; thus, areas that receive a lot of sunlight might benefit from installing such an underlayment.

However, synthetic sheet underlayment is often considerably more expensive than felt models, and while it has a low permeability rating, this feature means it's difficult to get optimum ventilation.

Pros

  • It has a longer lifespan.
  • It comes in a mid-to-lighter gray hue, meaning it retains less heat from the sun and does not get as hot.
  • It's durable since it's made of thermoplastic polymers. Also, it's less prone to ripping, shifting, and other damages.
  • It has a Class-A fire rating, meaning that when combined with a Class-A fire-rated roof assembly, it gives the best resistance to combustion or catching fire.
  • It can handle high-temperature environments.
  • It weighs roughly 2 to 4 pounds per roofing square, compared to 15 to 30 pounds per square for roofing tar paper.
  • It's made of polyethylene and propylene, which are both recyclable materials.

Cons

  • It is expensive.
  • It has a low permeability, meaning there is poor ventilation.

3. Self-Adhering Membrane Underlayment

Self-adhering membrane underlayment, as the name suggests, is a peel and stick product designed for direct application to the roof decking. You peel and stick. It's made from butyl-based adhesive or rubberized asphalt, which is mounted on a polyethylene carrier sheet.

This underlayment outperforms felt models in high-temperature conditions, making it a great option for installation in high-pressure places. Due to this ability, it's often sold as High Temp Underlayment rather than a Self-Adhering Membrane. Besides, this underlayment is ideal when a stronger air barrier is required. Plus, if your roof has large valleys and dormers, you will have superior ice dam protection in those areas as well as the eaves.

However, self-adhering membrane underlayment does not work well in low-temperature environs. Another issue with the self-adhering membrane is getting it installed correctly. Also, if not handled properly, a faulty installation might cause your membrane to peel back over time, leaving your roof exposed to infiltration.

Pros

  • Ideal option for high-temperature environments
  • Protects high-risk spots on the roof
  • Handy in making low slope roofs weather-tight.
  • It acts as an excellent air barrier and offers ice dam protection.
  • The rubberized properties keep it from ripping easily, offering continuous protection while installed and against extreme weather.
  • It can offer protection in areas with extreme temperatures up to 240oF.

Cons

  • Quite expensive when compared to other options
  • Installation is not easy as you would expect
  • Not ideal for environments with extended periods of low temperatures

Factors to Consider Before Buying the Best Underlayment for a Metal Roof

1. Function

Before buying the best underlayment for a metal roof, pay attention to the functionality. The higher the functionality of the underlayment, the more extensive specifications it will have. Therefore, check its specifics and determine if it's what you are looking for.

2. Brand

You might be wondering, does brand matter? The short answer is yes. Besides, a branded product wouldn't last a decade if it did not have its significance. Therefore, though brands differ from one thing to the next, you should always compare the brands of your products before purchasing them.

3. Customer reviews

When shopping for the best underlayment for a metal roof, ensure you go through the customer reviews. Reviews usually have the power to influence your buying decisions. In addition, we recommend evaluating other customers' experience with the underlayment to determine its reliability. Besides, this is a wise approach to getting a decent understanding of anything before purchasing it.

4. Price

Before purchasing the best underlayment product for your standing seam metal roof, consider the price. Besides, everyone wants to get the best deal possible. Don't get the impression that an underlayment will only be the best value when it costs more. Put into consideration all other factors before making the buying decision.

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About the author

Jacky Chou

Jacky Chou is an electrical engineer turned marketer. He is the founder of Indexsy, Far & Away, Laurel & Wolf, a couple FBA businesses , and about 40 affiliate sites. He is a proud native of Vancouver, BC, who has been featured on Entrepreneur.com, Forbes, Oberlo and GoDaddy.