While not visible, roof underlayment protects the roof’s structural integrity. It also creates a weatherproofing barrier as an extra layer of fortification.
Installing a roof underlayment has a wide range of prices, from $1 to $6 per square foot. That’s because it all depends on the types of materials, installation methods, and extra costs in the process.
What Is Roof Underlayment?
Roofing underlayment is a protective barrier on a roof deck. It goes before all the outer components, like shingles or tiles. Underlayment is essential for a strong and durable roofing system. Some of the main benefits include:
A flat surface for construction – When adding other roofing components, contractors will need a solid base primed for installation. A roof underlayment takes care of the issue by providing a flat surface ideal for building upon.
Deters water damage – Underlayment is a roof’s final line of defense against water damage. Shingles can keep moisture out for the most part, but they aren’t 100% resistant. If moisture seeps through due to extreme weather conditions, underlayment will stop the water from reaching the deck and causing rot.
Protects the roof from damage – In extreme weather conditions, the elements can tear shingles off the roof, exposing the deck to impact. Underlayment helps stop anything that could potentially cause damage or even puncture the structure’s integrity.
Considering the benefits above, underlayment is absolutely necessary for a fortified roof. Just because it isn’t visible doesn’t mean it doesn’t matter.
Average Total Cost of Roof Underlayment
The national average for roof underlayment replacement is between $800 and $1100, with the average American paying about $900 for 2,000 square feet of installation.
When looking at the lower price ranges, you can expect to pay $190 for 300 square feet and $9,020 for 3,000 square feet. However, keep in mind that prices can be much greater and fluctuate depending on the contractor.
| Material | Cost per Material | Installation Cost | Total Cost per Square Foot | Cost for 2,000-Square-Foot Roof |
|---|---|---|---|---|
| Asphalt-Saturated Felt | $0.05-$0.50 | $0.55 | $0.60-$1.05 | $1,200-$2,100 |
| Rubberized Asphalt | $0.60-$0.70 | $0.55 | $1.15-$1.25 | $2,300-$2,500 |
| Synthetics | $0.18-$0.90 | $0.55 | $0.73-$1.45 | $1,460-$2,900 |
Varying prices come from the complexity of the installation. Contractors frequently have to remove shingles from the roof structure, replace the underlayment and then place the shingles back again. It’s best to contact multiple services and request a quote.
Did you know? Some people add thermal roof coating to their shingles, known as “cool roofing.” This protective coat reflects the sun’s harsh UV rays, providing more efficient insulation and keeping the home cooler over the summer.
Roofing Underlayment Cost per Square Foot
To make the budgeting process easier, you might want to think in terms of cost per square foot.
The cheapest roof underlayment is made from tar and felt paper, costing $0.10- 0.80 per square foot.
Including the cost of professional installation, this amounts to $0.75 – 4.00 per square foot installed.
Cost by Underlayment Material
When it comes to roof underlayment material, you’ll have a wide range of options. This can accommodate both lower and higher-end budgets.
You’ll also want to consult a professional on which underlayment material is the best for your roof. Let’s closely examine some of the most popular options.
Asphalt-Saturated Felt Underlayment
This is the most common and cheapest option for roof underlayment. Asphalt-saturated felt is water resistant and has an adhesive back.
However, it’s prone to wear and tear, so it’s not as durable as other options and will need replacing sooner. Usually, asphalt-saturated felt costs between $0.05 and $0.50 per square foot.
Rubberized Asphalt Underlayment
A combination of rubber polymers and asphalt, rubberized asphalt is a high-performing underlayment material. With superior protection and waterproofing capabilities, it naturally forms tight seals around potential openings like nail holes and grooves.
It’s the perfect choice for houses in harsh climates with complex architectural structures and roofing. One square foot costs about $0.60 to $0.70.
Synthetic Underlayment
Synthetic underlayment materials offer convenience without compromising durability. They’re thinner than rubberized asphalt and felt but still highly water-resistant and easily create water-tight seals around vulnerable points in the roofing system.
It also has the additional benefits of being highly resistant to foot traffic during construction and mold after the roof has been fully installed. While more expensive than traditional felt options at $0.18 to $0.90, it has a longer lifespan.
You’ll also have to consider that the price ranges derive from different brands and types of paper. Manufacturers frequently have custom processes that can heighten some benefits over others, such as UV protection and superior sealing.
Roofing Underlayment Cost by Weight
When buying roof underlayment materials, you’ll have the choice of different weights. Rubberized asphalt and felt are typically sold in 15-pound, 30-pound, and 40-pound classes. Generally, the higher the weight, the more absorbent the material.
In terms of price, 15-pound underlayment usually costs between $0.06 and $0.13 per square foot, while 30-pound underlayment costs $0.12 to $0.22 per square foot.
The thickest 40-pound material costs $0.35 to $0.45 per square foot.
You’ll also have to consider a few additional factors when selecting the right material. These include:
Climate and location – If you live in a place notorious for harsh weather conditions, storms, and lots of rain, consider using rubberized asphalt or synthetic underlayment. Doing so ensures you won’t have to deal with water damage or replace the underlayment for long.
The roofing type and material – Your shingles and roofing also play a crucial role in which underlayment to get. For example, metal shingles attract more heat. This accelerates the deterioration of traditional felt. You’ll have to replace the underlayment sooner to ensure maximum safety.
Expert opinion – While it might be more expensive, you should consider an expert’s opinion regarding underlayment. This could be the contractor or even the manufacturer. Roof underlayment might come with a guide explaining what kind of shingles it is most compatible with.
Did you know? There’s such a thing as solar-powered shingles. These shingle types look ordinary, but they have specialized cells integrated into their structure, giving the home usable energy. They look unassuming, blend in with the home, and can sometimes be a replacement for regular solar panels.
Roof Underlayment Replacement Cost by Roof Type
Another consideration is your roof type. This will play a large role in the installation process. Some roofs might be harder to work with because of the complexity of square footage, specific slopes, or shingle removal.
If you’re not doing a replacement for a residency, you might also have to consider building codes. Let’s look at some replacement costs when considering the roof type.
The roof slope – Roof slope can often make the difference between buying a more expensive synthetic underlayment and a regular felt variation. The material doubles as firm footing for contractors making necessary installments. You’ll need a material that provides enough traction for safety and efficiency issues.
Square footage – The size of the roof is yet another important consideration when dealing with underlayment. The price is usually calculated per square footage. Depending on the materials and contractor, it can range anywhere from $0.70 to $4.10 per square foot.
Roofing material – This is probably the most important factor influencing overall underlayment pricing. Different types of shingles require different materials. As mentioned, metal shingles require a synthetic material to avoid rapid deterioration. Asphalt shingles can work with most materials. Other materials like slate require a breathable synthetic underlayment.
Further climate considerations – If you live in a hot climate, you should pick an underlayment made for breathable heat protection. In contrast, colder climate homes need materials that are especially resistant to water moisture.
What Is the Purpose of Roof Underlayment?
Roof underlayment has multiple purposes for your roofing system. Mostly, it helps with protection, giving it an additional layer of weather protection. Let’s closely examine all the purposes:
Protects the roof deck – Your roof deck will frequently be made from wood. When exposed to the elements like rain, snow, and sun, it can warp, rot, deteriorate, and swell over time.
Gives contractors good traction – Roof underlayment is also a safety precaution. Whenever contractors work on your roof, they’ll need a non-slip surface to avoid potential injuries. This is especially important when working with roofs that have a steep slope.
Efficient installation surface – Wood decks can have bumps, cracks, and imperfections that can ultimately sabotage roof installation projects. With proper underlayment, contractors will have a solid, flat, workable base to start building from.
UV protection – Let’s say you’re building a house over a long period. You’ve reached the deck, but continuing the building processes has been delayed. You can’t just leave the deck exposed, as the harsh UV lighting can damage it. Using the right underlayment material, you can leave the project as is for longer periods before returning to it.
A fire-resistant material – This is another essential reason for picking the right underlayment material.
Pros and Cons of Felt, Rubber, & Synthetics Underlayment Options
Some pros of felt underlayment options are convenience, affordability, and standard durability.
However, they can tear easily and have a shorter lifespan. Rubber underlayment options are more durable, stronger, and generally better than regular felt options. They also have a much higher price, making them less affordable.
Even more durable are synthetic underlayment options. They are strong and durable but have the benefits of being thinner and more breathable. Out of the three, they’re the most expensive.
Does a Metal Roof Need Underlayment?
Yes, all roofs need some form of underlayment. Metal roofs, in particular, benefit from synthetic rather than regular felt options.
However, rubber underlayment is also a great choice for those who need additional protection and longevity while still not overextending on their budget.
What Roof Types Need Tar Paper Underlayment?
Regular tar paper, or felt underlayment, is the most basic underlayment type. It’s best for wooden and asphalt shingles. Generally, it does a good job of stopping water damage though it can deteriorate over time. It’s a widely popular option due to its low cost.
Does Roof Underlayment Need to Be Breathable?
Generally, roof underlayment needs to be breathable, especially in higher-temperature climates.
However, it can also depend on your roof type. For example, concrete tiles are heavy as they must have an extra breathable synthetic material underneath them.
Other roof shingles, such as asphalt and wooden shingles, don’t necessarily need this benefit as much.
When to Replace Roofing Underlayment?
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While roof underlayment is made to last a long time, it can’t last forever. On average, you’re looking at about 20 to 30 years before it needs replacement.
This will largely depend on what material the underlayment is made of. For example, felt deteriorates considerably faster than synthetic underlayment.
Some cases in which you should replace underlayment include when you’re remodeling your roof in general, such as replacing shingles, when you can see visible wear and tear on the underlayment, or when there was a severe weather accident.
