Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.
Whether you are putting up a roof on a new house or re-shingling an old one, you need to take into account which underlayment is best for you to use. Building a roof is a big project that takes a long time, and you will want to ensure you choose an underlayment that works for your roof, your climate, and your circumstances.
You have many different options when choosing the underlayment for your roof. Choose the best underlayment for your roof so that you don’t have to redo your roofing anytime soon.
The Gator-Skin Synthetic Roof Underlayment has very positive customer ratings and seems to be one of the most reliable you can purchase.
This product is compatible with “asphalt shingles, residential metal, and cedar shake roofing in place of #15 and #30 organic felt.” It also “exceeds performance requirements of ASTM D4869 and ATSM D226.” These are standard specifications developed by ASTM International for asphalt-saturated organic felts.
One huge advantage of this underlayment is its use of Safe-Step technology. This technology is designed to make it safer to walk across the roof while doing the roofing work. It is supposed to increase walkability and traction to prevent dangerous slips while working. Gator-Skin also resists tearing, which is super helpful in avoiding having to buy a new roll because the first one tore in too many places.
This underlayment also has a Class A Fire Rating (UL 70). Since it is a Class A material, that means that it has the strongest fire resistance possible. So, this is a great choice, especially for those who live in areas prone to fires. It doesn’t only protect against fire, though! The company notes that this product can “withstand desert heat, pouring rains, and high winds!”
This product is applied by rolling it onto the roof, and it can cover a 1000.000 sq. ft. area. It is 42 inches wide by 285.8 feet long. Another thing that stands out is that it is only 23 pounds, making it easy to carry onto the roof. It also has a 25-year warranty to keep you protected.
One huge advantage of buying this underlayment is that it is part of the GAF Lifetime Roofing System. This system says that if you “Install any GAF Lifetime Shingle and add at least 3 qualifying GAF accessories and you will get a Lifetime ltd. Warranty on your shingles and all qualifying GAF accessories!”
So, making a roof with GAF products is a good way to make sure you are covered.
On the specification of this underlayment, like the previous one, it is made to improve traction for those working on the roof. Although, it does not implement the same technology as Gator-Skin synthetic to do this.
The product is also built to create less heat, which makes it more comfortable for those working with it. Its rough synthetic construction makes it so that the material resists tearing. Also, it does not absorb moisture, which in turn helps prevent wrinkling. It has a “non-asphaltic polypropylene construction,” which means that it will last longer than older felts that can fall apart over time.
This also has a Class A Fire Rating!
One roll of FeltBuster covers an area of 1000 sq. ft. It is 48 inches wide by 250 feet long—the product weight 27 pounds, which is still relatively light enough to carry onto a roof. FeltBuster is applied onto the roof through the use of nails.
This is another highly rated option for roof underlayment. The great part about it is that it is much less expensive than the previous two options! It meets ASTM D226 standards.
Although it is felt, it is still a highly rated product. Despite the advantage of synthetic materials, felt is still used by many professional roofers and should not be knocked despite being “old school.”
One slight disadvantage is that you may have to buy more rolls, as it only covers 200 sq. ft. Because it covers a smaller area, this would be a great choice for a smaller project such as a shed!
Also, it does weigh 57 pounds, which may make it hard to carry for some. Again, this further shows it will be best for those smaller projects you are taking on.
It should be noted that this product does have a Prop 65 Warning for California residents.
Although it may not be as impressive as the other two products, keep in mind that it has a 100% customer satisfaction rating and is a great option for roofing on the cheap. It does come with a 1-year limited warranty too.
This is yet another highly rated synthetic overlay. Lowes notes that this is stronger than felt underlayment and that it is sustainable in high winds. Also, like others, it is slip-resistant. This one is even slip-resistant in wet conditions!
You can also leave it exposed for up to six months! So, if you are doing a DIY roofing project, you don’t need to worry about getting it done all in the same weekend! Another bonus is that it can be used under “all major roof coverings.” This one size fits all idea is great for those who are unsure about what roofs can have what underlying!
This roll covers 1000 sq. ft. of the surface. It is 48 inches wide by 250 feet long. Also, like other synthetic underlayments. It only weighs 28 pounds, too! According to Lowes, it also has a 25-year limited warranty. So, it is a great way to be covered, especially since a roof is such a long-term investment.
The first thing you should know about this underlayment is that it ONLY works with asphalt shingles. So, this is not compatible if you are using any other roofing material.
If you are putting down asphalt shingles, though, this is a great option to choose! It is able to resist rearing around the areas where you fasten it to the roof. That way, you don’t have to worry about getting a sheet down only to tear it after getting most of it down.
They also have dual-surface slip resistance. This, similar to other underlayments, is a technology that helps prevent slipping, making it easier to work on the roof. One roll will get you 1000 sq. ft. of coverage. It is 42 inches wide by 286 feet long. Also, it is on the lighter side weighing only 25 pounds.
Also, this underlayment comes with a 10-year limited warranty.
This is another smaller roof underlayment great for those working on a budget and/or just doing a small roofing project! Since this is a felt underlayment, it does not have the same technology as its synthetic counterparts. But, this is still a great product, especially considering its low price!
This product is designed to lay down flatter when you are rolling it out. This should reduce the amount of wrinkling, compared to other felt underlayments. Also, compared to others, the asphalt saturation is stronger, which makes it more resistant to water and other destructive elements.
It also shares the slip-resistant technology that many others have. The extra peace of mind this brings is well worth the extra price you may pay. They have put lay lines printed onto the felt, which makes laying it out easier and more even. It covers an area of 216 square feet, and it 36 inches wide by 72 feet long. It is on the heavier end, though, weighing 36 pounds.
It should be noted that no warranty comes with this underlayment. Also, for California residents, it does have a Prop 65 warning.
This is another product that is part of the GAF Lifetime Roofing System! So, you can be sure that you are covered in your long-term rooming investment! According to their page on Lowes, this product is specifically made to protect those awkward areas in your roof, such as the area around your chimney.
For those that live in areas with snow, this underlayment protects against ice dams. In case you don’t know, an ice dam is, it is a “ridge of ice that forms at the edge of a roof and prevents melting snow from draining off the roof. The water that backs up behind the dam can leak into the home.”
So, you can see that this is definitely something you need to protect against, especially if you live in an area where there is high snowfall. This polypropylene roof underlayment is reinforced with fiberglass, which, similar to the synthetic underlayment, resists wrinkling.
It is also noted that it uses “dual-sided selvage (an edge produced on woven fabric to prevent unraveling) and split-back release film to help reduce labor.” This covers 150 sq. ft. and is 36 inches wide by 50 feet long. It does have a pretty hefty weight though, clocking in at 64 pounds.
It also has a Prop 65 warning. Despite this, though, it is still a great option, especially for those that live in those very snowy areas. It has a limited lifetime warranty, too! So, this is a great one to consider
GCP, who has been around for 35 years, boasts a host of advantages with this product, so I will highlight some of the most standout ones. It is supposed to adhere strongly to the roof deck, creating a seal that will keep out harsh weather conditions such as heavy rain and ice dams. It also creates strong seals around nails.
They have a “Ripcord split release on-demand,” which makes it easier to waterproof tight areas, such as those around chimneys. It is also compatible with many roof types such as “asphalt shingles, mechanically attached tiles, and most standing seam metal roofs.”
Under fiberglass shingles it has Class A fire protection, under organic felt shingles it has a class C protection. It covers 225 sq. ft. and is 36 inches wide by 75 feet long. It is on the heavier side, weighing in at 60 pounds.
For California residents, this has a Prop 65 warning. There is also a 10-year material warranty from the manufacturer. It should be noted that this type of underlayment is used to give extra protection and needs to be used in conjunction with a felt underlayment.
One big advantage of this underlayment is that it provides lasting adhesion to the roof deck without fasteners or primers. It also uses a rubberized asphalt that is supposed to seal around the roof fasteners once they are put in.
Also, it has the same ripcord technology that the previous product utilizes. This product covers 100 sq. ft. and is 36 inches wide by 36 feet long. It was a fairly heavy 36 pounds and has a 5-year limited warranty. Also, like others on the list, it does have a Prop 65 warning.
It should be noted that this type of underlayment is used to give extra protection and needs to be used in conjunction with a felt underlayment.
This underlayment uses Tri-Flex technology which is, “20 times stronger than felt,” and is more durable too, as it “can be exposed for up to 6 months.”
Also, because it light (28 pounds), it makes it easier to install. Home Depot notes that it is so easy that you install it with one person, as long as you know what you are doing (that doesn’t mean you can do it without anyone there. Always have a partner with you when roofing). Also, despite it being lighter, it can cover more area than a traditional underlayment.
Like many of the others, it also has slip-resistant tech. They recommend you use it with concrete, metal, or wood roofs. It covers an area of 1000 sq. ft. and is 48 inches wide by 250 feet long. It also has a great 25-year warranty.
Do Roof Shingles Need Underlayment?
Technically, you don’t necessarily need to install underlayment along with your new roof. But, it is highly recommended that you do install it because even though it may be more expensive to do so, it will be well worth it in the long run.
ProfessionalRoofers describe it as the membrane of a roof. It is there to protect your home from the elements that your roof will face. They protect your house from damage by things such as heavy rain, snow, ice, and they even make the roof more fire-resistant.
Even areas in the roof were there are gaps in the wood or holes from roofing nails are protected by underlayment. This is especially important to protect against, especially when it comes to moisture entering the house.
Small leaks are easily overlooked, and these small leaks can turn into huge problems, bringing things such as water damage and mold. So, in essence, it is built to neutralize damage from rain, snow, etc. that could otherwise occur if you did not use underlayment.
The strips are also breathable, which lets built-up moisture escape your house. So, although it is not required, it is highly recommended that you use roofing underlayment when installing your roof.
How to Choose Roof Underlayment?
The biggest things that matter when choosing roofing underlayment is the type of roof you are installing, the climate you live in, your budget, and the time the roof will take to finish.
- Roof Type: Typically, if you are using shingles, a felt underlayment is a good choice. In particular, “15-pound roofing felt protects while giving air room to move around.”
But the story is different if you are installing a metal roof, in which case synthetic is better. This is because metal roofing can trap lots of heat, and synthetic underlayment is more heat resistant. (Source)
- Climate: Climate is also a factor you need to consider when choosing your roof underlayment. Typically, synthetic underlayments will work better in hot climates due to their added heat resistance. But, people who live in northern areas that experience snow and windstorms may want to choose felt underlayments instead. (Source)
- Budget: Budget is another major factor to consider. Typically, synthetic is going to be more expensive as it is the new and flashy technology. So. If money is tight, there is no harm in a felt underlayment.
But, if you have the money for synthetic, and you live in a climate/have roofing that would work better with it, then synthetic is the way to go. (Source)
- Install Time: If you know the roof will be done fast, then felt is ok to use. But you want to get the shingles pretty much right after installing the underlayment. With synthetic, though, it can be left exposed longer. Some can last 90-180 days! (Source)
Roofing underlayments, well, they can be expensive. But just remember that that extra price will be well worth it in the long run, especially with all the extra protection that you get!
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