Roofing underlayment acts as a crucial secondary water-shedding barrier between your roof deck and asphalt shingles. The two most important types are synthetic underlayment (the modern standard for the main roof) and peel-and-stick ice & water shield (required for vulnerable areas like eaves, valleys, and vents).
5 Layers That Go Under Your Roof Shingles
Tar paper serves several critical functions that shouldn't be overlooked: Waterproofing: In our experience, it acts as a secondary barrier against moisture, ensuring that any water sneaking past your shingles doesn't compromise the wood beneath.
Yes, plywood is the standard foundation for asphalt roof shingles. However, you cannot nail them directly to the raw wood. Building codes and manufacturer warranties require an underlayment (like synthetic felt or tar paper) between the plywood and the shingles to prevent water damage and wood rot.
To tell if a roofer is lying, watch out for high-pressure sales, suspiciously low bids, and demands for large upfront cash payments. Honest roofers provide clear, detailed contracts and verifiable credentials. Always check their local license, avoid signing contingency agreements before fully committing, and get a second opinion.
Generally, the late fall and winter months can be the most cost-effective times to schedule a roof replacement. This is typically the slow season for roofing contractors, and as business wanes, you might find that they are more willing to negotiate on price.
1/2-Inch Plywood: Commonly used for residential roofing with rafters spaced 16″ apart. It is acceptable under many codes but may flex under heavy snow or foot traffic. 5/8-Inch Plywood: Offers better support and is often preferred in areas with snow load or roofs supporting solar panels.
All roofs have underlayment. At a minimum, a roof with asphalt shingles should be completely covered with one layer of underlayment. Roofers may consider adding layers of underlayment for superior protection, which is especially useful on low-pitch roofs.
Neutral and timeless roof colors like black, charcoal, gray, and brown consistently deliver the highest return on investment. These classic shades have universal appeal, seamlessly match nearly all architectural styles, and attract the widest pool of potential buyers.
Lack of Longevity: Despite tar paper underlay having years of usage, it does not hold up as long as a synthetic underlay, due to the makeup of the materials. The typical lifespan for tar paper is 10-20 years. You may not get as many “years” from a tar paper roof underlay as you could with a synthetic material.
You should never install metal roofing directly onto bare plywood. You need to install a protective moisture barrier (underlayment) between the plywood and the metal.
If your roof is newer and made of durable materials, like metal or slate, your homeowners policy may cost less than if you have an older roof — which may be more susceptible to damage and a risk for homeowners insurance companies. In some cases, your insurer may inspect your roof before issuing a policy.
Though this roofing component stays hidden, underlayment is the most important part because it provides protection for your home. Even if the most violent storms rip off shingles and cause a branch to fall on your roof and puncture the top layer, the underlayment is remaining on guard, keeping your home dry.
A good quality underlayment resists water fairly well. The thicker and stiffer it is, the better and longer it can protect against the weather. There are many reasons an underlayment could fail including: Poor quality - Underlayment made with subpar materials can't keep water out effectively.
The black paper installed under shingles is most commonly called roofing felt, felt paper, or tar paper. It is a type of roofing underlayment made from organic materials (like cellulose) or fiberglass, saturated with asphalt to repel water and protect the roof deck.
Synthetic Underlayment
Synthetic is a good bet! It's water repellant and tear-resistant, making it a top choice among many roofing professionals. Performance and longevity are big pluses, and it holds up well against prolonged sun exposure.
There is no practical lower or upper temperature limit governing when asphalt fiberglass shingles may be applied, as long as appropriate precautions are taken. In cold weather, for easiest handling, temperatures should be above 40° F. In hot weather, for easiest handling, temperatures should be below 90° F.
The 25% Rule in roofing serves as a guideline for both homeowners and contractors when planning roofing projects. Basically, it means that if more than 25% of your roof's surface needs repairs, it's often wiser to contemplate a full replacement rather than patchwork.
CDX plywood is the most common and widely used plywood for roof sheathing due to its durability, affordability, and exterior-grade glue, which resists moisture during construction.
No, they are different. A 23/32" panel is the standard thickness for nominal 3/4" plywood, while actual 5/8" plywood measures 19/32".
For a 2,000 square foot home with asphalt shingles, the installation typically takes 2-3 days, while the entire process from planning to completion usually spans 2-3 weeks.
What damages the roof the most? Sun exposure, poor maintenance, and severe weather like hailstorms and strong winds do the most damage.
Topics to Avoid When Speaking to a Home Insurance Adjuster