Choosing the Best Tesla Roof Underlayment for your Climate

solar roof underlayment

There are many decisions to make when getting a new roof, but homeowners usually think they only need to decide between standard shingles or metal roofing. Another decision one must make is the type of underlayment that goes directly between the shingles or metal and the roof deck and protects your house from further damage.

There are three main types of underlayment: fleece, synthetic, and rubberized asphalt, and the ideal choice of Tesla roof underlayment depends on the climate where you live and your type of roof. You should choose the best Tesla roof underlayment depending on the climate it will withstand.

Underlayment is laid under the roof’s covering and insulation and then lays on top of the deck. There are similar benefits to all types of roof underlayment, from being water and heat resistant to eliminating moisture from getting into the roof deck and home. Read on to find out more about what type of Tesla roof underlayment is ideal for your climate.

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Choosing the Best Underlayment for Your Climate

Underlayment is a barrier that goes between the roof’s deck and the top layer, whether it is shingles, tiles, or metal. It protects the home from water, moisture, and heat buildup, as well as chemicals that may leak from the shingles. It can also insulate the home from the noise of rain on a metal roof and insulate the attic from heat.

There are three types of underlayment that are offered when building a new roof:

  • Asphalt-saturated felt
  • Synthetic underlayment
  • Rubberized asphalt

Each type of underlayment has its pros and cons, from water-resisting and cost to safety of installation and heat resistance. When determining what type of underlayment in which to choose between the three to go under your Tesla Solar Roof, many individuals believe they just need to consider the type of roof.

In this case, the type of roof is a Tesla Solar Roof, and that has its own specifications. However, the climate in which you live is another important factor to consider since felt, synthetic, and rubberized asphalt have their pros and cons when it comes to dealing with snow, heavy rain and wind, and areas of extreme heat.

The type of underlayment depends on what your climate is most of the year and whether you need protection from rain, snow, heat, or wind. This is because the underlayment’s main job is to protect your home from the harms of weather and precipitation. Below are the benefits underlayment provides.

  • Water-resistant: The underlayment is what helps water slide off of the surface of the roof so that the roof does not weaken due to moisture buildup. All three of the options offer water-resistant protection, but felt is not waterproof, only water-resistant.
  • Barrier for heat and moisture: Most climates deal with sunlight, rain, and wind, and the underlayment will protect against the weather conditions that the top layer of your roof cannot endure.
  • Waterproofing: Some types of underlayment are waterproof, although many are simply water-resistant. A waterproof underlayment stops leaks during a heavy rainstorm. Waterproof rubberized asphalt and synthetic are better choices than felt for climates with lots of rain or tropical storms.

Choosing the correct underlayment for your climate is essential because damage from the elements can be catastrophic to a house’s foundation and roofing.

Asphalt-Saturated Felt for Colder Climates

Asphalt-saturated felt underlayment is a water-resistant paper made of organic cellulose or fiberglass, which is dipped in an asphalt, bitumen, and polyester mixture. Felt is the best choice for a traditional shingle roof and colder climates that are prone to heavy snowstorms and windstorms. Shingles should be installed immediately, so they lay flat.

Felt comes in 15-pound and 30-pound thickness options, and, although not waterproof, it is water-resistant. Therefore, it may not be ideal in wet areas that get a lot of rain. If you do live in a wetter climate and want asphalt-saturated felt, you should choose the 30-pound option because it is stiffer and thicker and protects roofs exposed to weather better.

Felt may not be recommended for a Tesla roof because the material cannot be left unexposed for more than a few hours, or it will dry out or leak oils in the heat and impact its moisture resistance. A Tesla roof may only take a day to install, but there have been roofs that have taken longer and have needed to leave the underlayment exposed.

Pros of felt:

  • Costs less than synthetic and rubberized asphalt underlayment
  • Better for shingles
  • Appropriate for colder climates that are prone to snow and windstorms

Cons of felt:

  • Disposed to tearing in winds during installation and cannot be exposed for more than a few hours.
  • Not ideal for very hot or wet climates.
  • Could wrinkle if exposed to felt, making it harder for the roof shingles to lie flat.
  • Harder to install because it weighs more and is slippery.
  • It may void the Tesla warranty if it requires a synthetic underlayment.

Felt used to be the most popular type of underlay until the availability of asphalt declined, leaving a hole for synthetic underlayment. That being said, felt is probably going to be more affordable than synthetic underlayment and could be used for the standard shingles in colder climates as long as your roof has a quick turnaround time.

Synthetic for Extremely Hot or Wet Climates

Synthetic underlayment has advantages over felt and is ideal for metal roofs because it is more heat resistant to protect metal roofs that trap heat more easily than other types of roofs. It is made from a mixture of polymers and polypropylene and is ideal in hot and wet climates because it resists moisture better and protects from the sun than felt.

You should do your research before deciding to use synthetic underlayment because different brands vary in quality. Tesla has been known to use a standard roofing underlayment for metal roofs called Firestone’s CLAD-GARD SA-FR. Unlike felt, this option is safer for the installers because it weighs less and is slip and skid resistant.

Synthetics are superior over felt in very wet areas because they are waterproof, stronger, tear-resistant, and elastic. Because synthetics do not absorb moisture, they are also fighters of fungal growth and wrinkles. They are also ideal in very hot weather because synthetics protect your roof’s surface from extreme heat and are UV resistant.


  • Moisture-resistant and waterproof
  • Resistant to tears
  • Fast and safe to install because it weighs less and is slippery-resistant
  • Ideal for extremely hot or wet climates
  • Resistant to both wrinkles and fungus since they do not absorb moisture

The only real con of synthetic underlayment is the price compared to the felt underlayment. If you live in a very hot or very wet climate, synthetic underlayment is a viable option for using a Tesla roof. In fact, the Firestone option fits into this category if it is still offered by Tesla. And, it is probably cheaper than the third option, rubberized asphalt.

Rubberized Asphalt Works in Any Climate

If your climate includes fighting off rain, tropical storms, or, worse, hurricanes, rubberized asphalt may be the right choice to protect your home. Rubberized asphalt is a waterproof underlayment that contains high amounts of asphalt and rubber polymers. Rubberized asphalt is the only choice that uses a 100 percent waterproof seal.

How is rubberized asphalt waterproof?

  • The mixture of high concentration of rubber polymers and asphalt create the 100 percent waterproof seal, the only type of underlayment that has this option.
  • It is a seal-sealing underlayment, which works well with fasteners, and includes fiberglass or a polyester film to prevent moisture buildup.

Rubberized asphalt may be designed to resist extreme heat, but they are also excellent for colder regions that deal with snow since it is waterproof and moisture resistant. They can also be safe since rubberized asphalt is non-skid and light in weight. However, all of these benefits come with a much higher price than both felt and synthetic underlayment.

Due to being ideal in both extreme cold and extreme heat, rubberized asphalt can be installed under metal roofs in the most severe environments. It also protects against the most common roofing problem, which is the leakage of water. That being said, those on a budget or who have financial limitations may want to stick with the synthetic option.

Which Type of Underlayment Does Tesla Offer?

In 2020, reports came out that a customer who purchased a Tesla Solar Roof was left without a roof and only tarps covering his home for months. There were numerous reasons for the delay, but one of them may have been when they started laying the roofing underlayment. The report said the company was trying a new product.

Tesla soon realized they made a mistake with the new underlayment, stating it was too thin and the clips that held the boards could allow water in when it rained. Note that the main point of an underlayment is to protect the home from water. Therefore, it is important to have an understanding of what underlayment is being used for protection.

Some Tesla customers have reported that the company is now offering underlayment from FT Synthetics, and the horror story above did not use the Firestone product, but the official website is showing the Firestone CLAD-GARD SA-FR. This underlayment that is featured on the Tesla Website as their weatherproofing layer has its benefits:

  • Waterproof
  • The service temperature is a maximum of 230 degrees Fahrenheit
  • Slip-resistant and safe for the installers
  • Safe to be exposed for up to 90 days during the roof’s construction (although the roof should not take that long)

The roof itself has a 25-year warranty on the tiles, the power, and the weatherization, along with impressive wind and fire ratings, so you may not think you need to worry about the type of underlayment. However, Tesla customers have been touting other underlayment products, so it may depend on the climate in which you live.

Underlayment for Solar Roof

The Tesla roof does cost more than simply adding solar panels to an existing roof, but it also comes with numerous benefits. Basically, the company has found a way to use a building-integrated photovoltaic (BIPV) product that incorporates solar panels into the roof shingles. The roof then generates solar energy without the need for solar panels.

Some individuals have found Tesla’s Solar Roof to be a perfect combination of using energy-saving solar capabilities while also having the aesthetics of a sleek roof, not solar panels on top of a roof. Many solar users have voiced how visually unappealing solar panels are, so installing an entire Solar Roof has alleviated this complaint.

The cost of an entire Solar Roof is estimated at more than $30,000 – quite higher than replacing a standard roof but coming in with all of the savings on your electric bill. Tesla is advertising its Solar Roof at $1.99 per watt, which is below the average of $2.99 per watt for solar panels. But a roof comes with other decisions, including the underlayment.

Tesla Offers Solar Panels and Full Roof Replacement

Tesla offers both Solar Panels and an entire Solar Roof. If you are just purchasing solar panels (or, in some states, renting), you do not need to worry about what underlayment you currently have on your roof. The underlayment is determined by the type of roof you have, whether it is shingles, metal, or clay, and the climate in which you live.

Tesla has a team of professionals who will remove your existing roof, install underlayment for waterproofing, install the new roofing tiles, and then clean up and activate the new Solar Roof. The roof comes with a Tesla solar inverter so that the DC power that is generated from the sun can be converted to AC power for your home.

If you have discussed replacing your entire roof with a Tesla Solar Roof, then you definitely need to determine what type of underlayment will go under the roof and above the deck. For a long time, Tesla was using Firestone’s CLAD-GARD SA-FR, which is a typical underlayment for metal roofs, and this is the example illustrated on their website.

The Tesla Solar Roof comes in four designs of glass tiles:

  • Tuscan
  • Slate
  • Textured
  • Smooth

What type of underlayment is best for glass? Is it the Firestone CLAD-GARD SA-FR that is featured on the Tesla Website or another version? There are many benefits to choosing the correct underlayment that compliments your type of roof, including the glass tiles used by Tesla. If you do not choose the right one, the benefits may be moot.

Balancing Climate with the Needs of Glass Tiles

A Tesla Solar Roof can be a great way to fully replace your roof while saving money on your electric bills and helping the environment. As discussed, there are different reasons why one type of underlayment will work in a particular climate over others, and you need to recognize what weather-related issues your house endures over the year.

  • Felt – The most affordable option and could be used in colder climates.
  • Synthetics – Ideal for very wet areas and climates that deal with extreme heat.
  • Rubberized Asphalt – The most expensive option, but it could be used in all climates, including very wet areas with rain, tropical storms, and hurricanes, areas of extreme heat, and colder regions that deal with snow.

Because a Tesla Solar Roof uses glass tiles, you will need to balance the needs of the climate in which you live with the needs of glass tiles. If you do not want to use the Firestone CLAD-GARD SA-FR option and you live in a colder region, you may be able to use a heavier felt to save money. However, you need to focus on the water barrier.

Glass tiles used by Tesla are said to be three times stronger than standard tiles and are engineered to have all-weather protection. The Firestone CLAD-GARD SA-FR is a synthetic roofing underlayment for roofing slopes that are steeper than 5.12 and is said to be water and fire-resistant. If your climate is compatible, it may be an easy choice.

The Firestone option may also come with a 20-year Firestone warranty, and this should be researched before making an underlayment decision (although most underlayment choices should have a warranty). In the end, you should speak with a professional and then choose an underlayment that meets the waterproofing and heat needs of your climate.


Weather can destroy a roof, cause leaks, and even have heat-related problems, and the proper choice in underlayment is key for protection. Tesla offers options for underlayment for their Solar Roof, including the Firestone option illustrated on their Web site and other options discussed by customers. Determining which one is best depends on the climate.

Firestone is an appropriate synthetic option and works well for wet areas and climates that deal with extreme heat. Felt underlayment could save money in colder areas, but is the money savings worth the protection the home may not receive? Rubberized asphalt works everywhere but is expensive and may not be under a Tesla warranty.

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The articles here on are created by Greg, a Tesla vehicle and Tesla solar expert with nearly half a decade of hands-on experience. The information on this site is fact-checked and tested in-person to ensure the best possible level of accuracy.

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