Your home’s roof is a lot more complex than you think, and many homeowners don’t even know what each layer does. Despite a roof’s value in keeping your property safe, it’s helpful to be aware of other features. Your local reliable roofer will tell you that underlayment is one of those important features.
Below, we examine the basics of underlayment and why it declines. For protection against moisture, underlayment is laid directly on top of your roof’s flat-lumber pieces (large flat wooden sheath boards). This component isn’t directly exposed to the weather and only acts as a secondary layer of defense. It keeps sheathing dry.
But it’s more complicated than just that. A roof underlayment will:
- Make your home even more water-resistant. It helps prevent leaks during heavy rain, high snow accumulation, and severe storms.
- Protect your roof from damage if shingles are blown off during a hurricane or other bad weather. You can keep the roofing underlayment until the damage has been fixed or the shingles have been replaced.
- Help your roof avoid leaks caused by moisture penetrating the roof.
- Keep your home from getting drafty with extra insulation.
- Soundproof your roof from rain or other elements.
- Make sure the roofing material looks even and uniform.
- Validate your roofing warranty if you have one.
A Reliable Roofer is the Expert on Underlayment
Here are you basic three underlayment:
- Felt (asphalt-saturated felt underlayment). A reliable roofer will agree this is the cheapest option. It’s made by waterproofing felt paper with asphalt. However, it does make the roof deck stiffer, providing durability against airborne debris, hailstones, and large tree branches.
- Rubberized (rubberized asphalt underlayment). Asphalt and rubber polymer make rubberized asphalt underlayment waterproof. Using special adhesives, rubberized asphalt is installed just like membrane roofing material on flat roofs. In addition to being the most expensive option, it’s also the most popular choice for homeowners living in certain climates.
- Synthetic (non-bitumen synthetic underlayment). Due to its superior waterproofing properties, many roofing contractors choose non-bitumen synthetic underlayment for modern roofs. From food-grade containers to plastic models, these newer materials are made from hard-wearing plastics like polyethylene and polypropylene. This option usually offers (but not always) middle-of-the-road price convenience simultaneously with quality materials.
Some homeowner experts and consumer advocates even have their own top choices for underlayment brands and manufacturers.
Deeper Homework and Things to Note
There are different kinds of non-adhesive synthetic roofing underlayment. Underlayment brands range from high quality to low quality. With lousy products and fancy marketing, some underlayment manufacturers may try to trick you — but you can outsmart them.
You can tell a lot about the quality of the synthetic underlayment by its weight. Waterproofing and abrasion resistance are both in the membrane layer. Underlayment brands that advertise millimeter thickness are trying to save money. Some of these underlays have a fuzzy top layer for walkability, which can give a false feeling of their thickness.
A reliable roofer would argue the following: to make sure you have the best synthetic roof underlayment, look at weight instead of millimeter thickness.
In spite of this, synthetic roof underlayment is the most popular underlayment material. Originally, synthetic underlayment was made to solve the problems felt underlayment had. Felt was the material of choice for roofing underlayment for so many years in the past until synthetic underlayment hit the market over the past two decades as an improved product.
Synthetic underlayment lasts longer and won’t need to be replaced as often as felt underlayment. With felt, the installation costs were higher because it’s heavier and harder to install. You have to cover the felt once it’s installed so it doesn’t get damaged by outside elements. Also, felt isn’t as safe for roofers to walk on as synthetic, making installations more dangerous. It’s easier to tear felt underlayment, too.
Underlayment Facts, According to a Reliable Roofer
Any underlayment is at risk of deteriorating, like most layers. In the event it gets damaged, you might have roof leaks, mold colonies, and structural problems with your house. It’s important to know what compromises the integrity of your roof’s underlayment so you can prolong its life. Here’s what you might expect:
- Poor care or amateur installation. It’s important for contractors to make sure underlayment isn’t torn, wrinkled, or damaged. The underlayment should also be installed with manufacturer-approved fasteners so it performs like it should without voiding the warranty. Make sure contractors are up to the job before they install it. It’s also common for underlayment not to last as long as it should when it’s mishandled. The underlayment can be compromised in this case. It’s important to note that incorrect installation can damage the underlayment in several ways, leading to failing early or causing other problems with the roof. Contractors could tear the underlayment instantly if they don’t tread carefully. Your local reliable roofer is usually the best option for this job.
- Material is low quality. Roof replacements need quality materials. Buying low-quality underlayment means you’re likely to get what you pay for. To meet different needs, manufacturers offer many pad options and provide components that are compatible. For instance, some residential home projects by builders use synthetic and fiberglass-reinforced underlays. Underlayment can be low quality, especially with asphalt roofing felt. The underlayment on a roof that’s poor quality degrades and fails much faster than the roof. A low-quality underlayment might seem cheaper, but it’s often a bad idea because it lets water seep through and damage the roof deck. You’ll end up paying more later if you save money on cheap alternatives.
- Re-shingling was delayed. The temperature can really affect your underlayment. When the shingles covering the underlayment are missing, the underlayment is a sitting duck for harsh elements. The weather can impact even high-quality underlayment materials if they’re left out for too long.
- Extreme heat. It’s not just the roof that can crack and blister, but also the underlayment. It happens because tar softens during the roofing installation process, making the product more vulnerable to damage.
- Wetness, moisture, and water. In some cases, water can reach the underlay when it rises below the edge of the shingles. Tar paper is usually used for asphalt shingle roofing because it’s made of tar-embedded paper. Underlays nowadays may also contain fiberglass. It’s hard to put water within a primarily-paper substance. As a result, tar paper can swell, wrinkle and warp, allowing moisture to penetrate and the underlayment to lose its protection.
- VOCs disappear. Asphalt underlayment contains volatile organic compounds (VOCs) that initially add to its toughness. However, these compounds degrade and evaporate over time, especially in hot weather. It becomes more moisture absorbent — and thus, more prone to failure when that happens.
- UV exposure. Ultraviolet sun rays can also damage underlayment. Each type has a different tolerance. For example, when exposed to UV rays, asphalt felt deteriorates quickly, so it needs to be covered right away. However, synthetic underlayment does better in this regard. Some products, can give you up to 180 days of UV exposure should the need arise.
- Wildlife. Wild animals aren’t something we think about when it comes to roofing, but they can damage underlayment. If they want to get inside, raccoons and squirrels can rip shingles and underlayment. That’s why trees should be trimmed well away from homes to prevent wildlife damage.
What’s also interesting: some roofing experts especially focus on roof “valleys”, the area where two slopes join together. For some roofs to have a long-lasting watertight assembly, self-adhesive underlayment and critical attention to the roof valleys is crucial. A reliable roofer near you is key to helping you understand these issues, where most homeowners just aren’t the experts.
Risks of Underlayment Damage
Remember, you can’t see the underlayment because it’s installed between the shingles and roof deck. It’s important to check it from time to time for damage. A damaged underlayment can lead to any of these problems if it’s left in poor condition:
- Damage to the structure. Underlayment keeps things dry and light so your wooden sheaths don’t have to lift unnecessary weight from moisture. Your home’s frame may buckle or rot if your underlayment — and roof shingles and sheathing — get wet.
- A moldy mess. You may notice there’s a lot of darkness and dampness in the underlayment. Mold can grow in water-damaged walls of your home, too. The mold in your house can be toxic, so you should fix it as soon as possible.
- Leaks. It’s possible for your underlayment to pool water, which will eventually seep into your walls and ceilings. You can tell if your roof is leaking from the inside by looking for light beams, dripping water, or dark stains. Once that’s finished, call your local reliable roofer to have it looked at.
It’s an honor for Keystone Roofing and Siding to help educate consumers and homeowners about the health and safety regarding one of their most important assets. Please contact us with your questions or to set up an appointment.