In roofing, underlayment refers to a component laid beneath all of the roofing layers and directly on the roof deck. The underlayment serves as an additional weather barrier against the elements, such as wind-driven rain and snow. The shingles provide the principal weather barrier.
Roofing underlayment, or felt, shields the roof deck from the rain and snow and is installed between the roof deck and the shingles. Since shingles are frequently tested on roofs with underlayment, they generally require synthetic underlayment or asphalt felt to get the required fire rating.
Below we will look into the best underlayment options you might need to protect your roof from rain and snow damage. There are numerous benefits to using underlayments under your shingles, so find out below how it could help you.
What Is Shingle Underlayment?
The layer that lays between the shingles and the roof sheathing, also known as the roof deck, often comprised of plywood or OSB, is referred to as roof underlayment. It is placed directly on the roof deck and provides an additional layer of weather protection from rain, snow, and wind. In addition, the shingle underlayment aims to offer a moisture-resistant layer beneath your roof shingles.
Due to continual advances in the construction materials industry, synthetic underlayments have dethroned felt-paper as the most used shingle underlayment.
In current roof systems, two separate underlayments can be employed to give the best possible protection from the elements. The first underlayment is a piece of waterproof ice and water membrane installed along the roof’s perimeter to avoid ice damming. The second underlayment is a tear-resistant, water-resistant material covering the remaining portions of the roof deck while also providing a high-traction walking surface for roof installers.
While more expensive than felt, synthetic underlayments are lighter in weight, better at lying flat and resisting water, to the point that high-end synthetic underlayments may be used as temporary, short-term roof coverings.
Roofing felt protects your roof and your home in various ways. Consider the following scenarios:
It deflects water: Water can pool beneath your shingles due to wind-driven rain or snow, putting your roof deck and interior at risk of moisture damage, leaks, rot, and mildew. Roofing felt helps water drain from the roof and keeps it from seeping into your home.
Fire resistance: To acquire a decent fire rating, you may need to use roofing felt in addition to your shingles. When shingles are tested for fire resistance, they are placed on a small test deck with the roofing felt underlayment in place; if the underlayment is not there, the shingles may not meet the required fire protection standards.
It improves the appearance: Because your roof deck may not be perfectly straight or flat, a coat of roof paper creates an even, homogenous surface on which you can apply your shingles. It can also prevent the wavy or picture framing effect when the pattern of your wood decking telegraphs through your shingles by putting an extra layer on top of uneven wood.
The Advantages Of Underlayment For Roofs
Underlayment is an essential but frequently unnoticed component of today’s home roofing. Felt Paper and Ice and Water Shield are two familiar names for roofing underlayment. In the event of damage to the outer waterproofing layer, it protects the roof deck or substrate against water incursion.
- The underlayment protects the deck while the shingles are being installed.
- Water that passes through the shingles is resisted by the underlayment, ensuring that it runs off the roof and does not soak into the building.
- Some underlayments can assist the shingles in meeting the Class A fire rating.
- Underlayment aids in the installation of shingles by providing a consistent surface.
- The use of underlayment between the decking and the roof shingles results in a roof that lasts longer and looks better.
Shingle Underlayment Types
Underlayment is essential regardless of the type of asphalt shingle used, whether traditional or more durable varieties such as luxury, architectural, or strip shingles. So underlayments are precisely what they sound like: they’re underlayments for finished products.
These four underlayments are all shingle underlayments that go between the shingles and the roof deck or wherever the plywood or one by one is installed. The decking functions as a second layer of protection in the event that something goes wrong.
Asphalt-Saturated Felt Paper
The earliest underlayment material, asphalt-saturated felt, gave rise to the industry terms “roofing felt” and “felt paper.” The backing substance is similar to tar paper in function, except the waterproofing element is asphalt rather than tar. Felts was formerly the most popular underlayment alternative, but as asphalt supplies dwindled, other materials took their place.
Asphalt-Saturated Felt Paper is wood pulp and other organic components crushed together to produce paper. It is essentially a basemat, which works as a flexible base layer, and is used to create all sorts of underlayment. Then it’s covered with an asphalt layer, which helps the basemat to achieve water resistance, so it doesn’t absorb it.
Rubberized Asphalt Underlayment
Due to the larger volumes of rubber polymers and asphalt used to create rubberized asphalt underlayment, this combination makes an entirely watertight barrier, but it comes at a high price. In addition, many of these peel-and-stick underlayment materials are fire-resistant, which is a significant benefit in terms of the amount of protection you gain by installing them.
Rubberized asphalt refers to a range of underlayments with one thing in common: they all have a rubber-like appearance and feel. The majority of these underlayments are peel-and-stick, which means that instead of using fasteners, installers peel off the membrane and apply it to the roof.
Because this underlayment is wrinkle-free, it produces a waterproof barrier that prevents water from pooling and potentially penetrating the roof structure. Another benefit of this underlayment is that it is easy to install and does not require nailing but will self-seal. The lack of nail holes creates a more effective barrier against moisture and mildew.
These underlayments do a great job of protecting a roof from water damage, and they’re also more heat resistant than asphalt-soaked felt, so they’ll stay longer once placed. However, rubberized asphalt can also be exposed to the weather for 90 to 180 days when roofers need to wait a while before putting the principal roof covering shingles on.
This peel and stick underlayment features a flexible facer that adapts to roof flaws, unlike asphalt underlayment, which tends to fracture, rip, and peel.
Synthetic Underlayment With No Bitumen
Since the early 2000s, many forms of synthetic underlayment have been available. However, polyethylene or polypropylene gets used to weave or spin the majority of synthetics. In addition, synthetic roofing underlayment materials are not standardized, so different manufacturers may make their products differently and have different performance levels.
Roofing felt rolls are 3-feet long and cover an area of approximately 400 square feet. Synthetic underlayment rolls are 4-feet long and cover an area of about 1000 square feet. It doesn’t take a roofing scientist to figure out that larger rolls can cover a roof faster, and more coverage per roll means fewer visits to get more product.
Synthetic underlayments are substantially lighter than asphalt and have higher wind resistance and rip strength. Although many synthetics are reasonably priced, the most significant disadvantage of synthetic roofing underlayment is its expense compared to felt. However, making an initial outlay in higher-quality roofing materials may save you money in the long run.
You can’t put a premium on the peace of mind knowing your roof is well-protected against moisture. So be sure to do your investigation and talk with a trusted contractor who can help guide you in selecting the suitable roofing materials to protect your home.
Where And When To Install Ice And Water Shield
It may be necessary to use ice and water shielding in certain situations. However, even if it is not required in your location, this underlayment type is typically a sensible choice since it provides an additional layer of protection against moisture. These underlayments are particularly well-suited for use in places that are subjected to extreme weather conditions.
An ice and water shield is a self-adhesive leak barrier modified to form a tight seal around the nails used in shingling. Self-stick or peel-and-stick tape is similar to this product, which comes in a sheet with a split rear release film. Skylights, dormers, vent pipes, chimneys, and other locations covered by flashing are some of the places that will require ice and water shield protection.
Having ice and water shield built on or around particular portions of your roof is critical, such as roof valleys, around penetrations, and roofs tops with a 2/12, 3/12, or 4/12 pitch. If you dwell in a region of the United States above the snow line, you’ll most likely have two rows of ice and water shield installed along with your roof’s rakes and eaves, following local building requirements.
It is required by this regulation that you install an ice and water shield around the edges of your roof to avoid leakage caused by ice damming following a significant snow or ice storm If you reside in a snowy climate.
Various Types of Roof Shingles
Asphalt shingles are an excellent roofing choice for almost any home. Today’s three primary asphalt roofing shingles are strip shingles, dimensional shingles, and luxury shingles. Asphalt shingles are long-lasting, low-cost, and come in various colors. However, to select the best roofing shingle for your home, you must first understand each type of shingle.
Strip Shingles: What Are They?
Strip shingles, often known as 3-tab shingles or just strips, are the oldest and most basic asphalt shingles. They are the most basic shingle, consisting of a single sheet of asphalt that has been cut into strips. When fitted, they seem flat, giving your roof a slate impression. 3-tab shingles are lighter and less costly than other shingles since they are made from a single strip.
Before the emergence of designer shingles in the 1980s, strip shingles were the most prevalent roofing shingle. Strip shingles are most typically used by homeowners replacing roofing shingles on homes that already have strip shingles on the roof or by housebuilders who are building low-cost residences.
Asphalt-Saturated Felt Paper is generally used with this type of shingle since it is more cost-effective on a budget.
Dimensional Shingles: What Are They?
The most prevalent asphalt shingles are dimensional shingles, often known as architectural or laminate shingles. These materials are made up of more than two layers of asphalt fused together to provide a thicker, more multi-dimensional appearance and are supposed to resemble wood shake and natural slate roofing.
Dimensional or architectural shingles have the disadvantage of being heavier than 3-tab shingles; therefore, they add to the weight of your roof. They are, nevertheless, more robust and come with a more substantial warranty due to their multiple layers. In addition, synthetic or asphalt underlayment works well with this shingle roof.
What Are Luxury Shingles And How Do They Work?
Luxury shingles are the highest-quality laminated shingles available, having an appearance and functionality that sets them apart from dimensional shingles. They are the most faithful representations of wood shake and slate roofing while significantly less expensive.
These laminated asphalt shingles are distinguished by their aesthetics and effectiveness, providing excellent weather protection. They are now available in several sizes, colors, and designs to suit a variety of climates and household needs. Glass fibers are glued to asphalt shingles with regular adhesive to strengthen and provide durability while also offering water resistance.
A base mat, a waterproofing asphalt layer, and a coating of ceramic granules are the three layers that makeup asphalt shingles. Granules added to asphalt shingles give color variety and UV protection. Since you are not concerned about the price of the shingles and want a roof that is both beautiful and functional, we suggest using only the best synthetic underlayments.
Conclusion
For a new home or a re-roofing job, there are many considerations to consider when choosing the type of underlayment to utilize. Underlayment linings are one of your roof’s primary defenses against inclement weather, including rain, snow, hail, and other potentially hazardous precipitation. So when your contractor suggests using this for your shingle roof, this shouldn’t surprise you.
Synthetic roofing underlayment may be better than felt because of its many benefits.
References
- https://www.owenscorning.com/en-us/roofing/tools/synthetic-vs-felt-roofing-underlayment-pros-cons
- https://www.certainteed.com/residential-roofing/types-asphalt-roofing-shingles/#:~:text=Different%20Types%20of%20Roof%20Shingles,right%20product%20for%20your%20home.
- https://www.latimes.com/archives/la-xpm-1999-jan-17-re-64327-story.html#:~:text=Answer%3A%20Roofing%20felt%20is%20a,or%20a%20built%2Dup%20roof.
- https://inspectapedia.com/roof/Roofing_Underlayment_Requirements.php
- https://designingidea.com/peel-and-stick-roofing-pros-and-cons/#:~:text=The%20peel%20and%20stick%20roofing,in%20hot%20and%20humid%20areas
