Is Tar Paper Waterproof? The Truth Behind Its Durability

Is Tar Paper Waterproof?

Yes, tar paper is waterproof.

It is a heavy-duty paper that is impregnated with tar, which creates a waterproof barrier.

Tar paper is commonly used in construction, particularly for roof construction, as it provides protection against moisture.

It is often used as roofing underlayment with different types of roof shingles.

Tar paper comes in various grades, which are based on the amount of time it takes for a moisture-sensitive indicator to change color when floated on water.

The higher the rating, the heavier and more moisture-resistant the paper is.

In addition to its waterproof properties, tar paper is also applied with different adhesives and can be used in multiple layers for added protection.

Key Points:

  • Tar paper is waterproof and creates a waterproof barrier.
  • It is commonly used in construction, specifically for roof construction.
  • It provides protection against moisture and is used as roofing underlayment.
  • Tar paper comes in various grades, with higher ratings indicating heavier and more moisture-resistant paper.
  • It can be applied with adhesives and used in multiple layers for added protection.
  • Tar paper is impregnated with tar and is a heavy-duty paper.

Did You Know?

1. Tar paper, also known as roofing felt or building paper, is a heavy-duty material made from a mixture of bitumen (tar) and cellulose fibers. Although it is not completely waterproof, it does provide a certain level of water resistance.

2. When tar paper was first used as a roofing material, it was often soaked in a mixture of tar and petrolatum to increase its waterproofing capabilities. However, modern tar paper is manufactured with improved waterproofing properties and does not require additional treatments.

3. Tar paper is commonly used in construction as an underlayment beneath shingles or other roofing materials. Its primary function is to provide an extra layer of protection against water infiltration, helping to prevent leaks and extend the lifespan of the roof.

4. While tar paper may not be completely waterproof, it does offer some degree of vapor transmission. This means that it allows moisture vapor to pass through, reducing the chance of condensation buildup within the roof structure.

5. Tar paper is not only used in roofing applications but also finds its use in other areas. It can be used as an underlayment for hardwood flooring, as a moisture barrier in crawl spaces, or even as a temporary protective covering during construction projects. Its versatility makes it a widely utilized material in the construction industry.

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Construction Use And Composition

Tar paper is a heavy-duty paper commonly used in the construction industry, specifically for roof construction. It serves as an essential component of roofing systems, providing a reliable barrier against water penetration. The paper is impregnated with tar, a sticky black substance derived from petroleum, which gives it its waterproofing properties.

While tar paper is similar to roofing felt, it is usually lighter and less durable. Its primary purpose is to serve as a protective underlayment for various types of roof shingles. Typically, it is applied in rolls of different widths, lengths, and weights, and can be stapled or nailed in place during installation.

Grades And Rating System

Tar paper is graded based on a rating system that indicates its resistance to moisture. This rating system determines how long it takes for a moisture-sensitive indicator to change color when floated on water.

Common grades of tar paper include 10-, 20-, 30-, and 60-minute papers, with a higher rating indicating a heavier and more moisture-resistant paper.

The rating system allows contractors and builders to select the appropriate grade of tar paper for a specific project. In regions prone to heavy rainfall or where extended waterproofing is required, a higher-rated tar paper is typically chosen to provide optimal protection against water damage.

  • Tar paper is graded based on moisture resistance
  • Rating system measures time for color change in water
  • Common grades: 10, 20, 30, and 60 minutes
  • Higher rating means heavier and more moisture-resistant
  • Contractors choose grade based on project needs
  • Higher-rated tar paper used in regions with heavy rainfall or need for extended waterproofing

“The rating system allows contractors and builders to select the appropriate grade of tar paper for a specific project.”

Applications And Installation

Tar paper is primarily used as an underlayment in roofing systems. It serves as a secondary barrier to protect the roof structure from moisture infiltration. During installation, tar paper can be applied using hot asphalt, cold asphalt, or non-asphaltic adhesives, depending on the project’s specific requirements and preferences.

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When properly applied, tar paper forms a waterproof barrier, preventing water from seeping into the roof and causing damage to the underlying materials. It also provides protection against harsh weather conditions, including wind and UV radiation. Additionally, tar paper is a versatile material suitable for both residential and commercial construction projects.

History And Replacement

Tar paper has a long history in the construction industry. In the past, it was commonly used as a waterproofing material for walls. However, with technological advancements, breathable plastic housewrap has largely replaced tar paper for this purpose. Housewrap offers better moisture management and allows for the diffusion of water vapor, reducing the risk of mold or rot within the walls.

Nevertheless, tar paper remains widely used in roofing applications, especially in the temperate American South and regions with similar climates. Its durability and ability to withstand heavy rainfall make it a popular choice for roofing projects. Made from virgin kraft paper impregnated with asphalt, tar paper can be applied in multiple layers for increased waterproofing capabilities.

Tar Paper In Rural Housing

In the 19th and early 20th centuries, tar paper played a significant role in rural housing, particularly in the form of tar paper-covered shacks. These simple structures were commonly used for temporary or low-cost housing in rural areas. Tar paper provided a basic level of waterproofing, protecting the inhabitants from the elements.

Although tar paper-covered shacks have largely been phased out as housing options, the historical significance of tar paper in rural communities cannot be understated. Its affordable and accessible nature made it an important building material during a time when resources were scarce and traditional construction methods were not always feasible.

Today, tar paper continues to be a vital component in modern construction practices, ensuring the durability and long-term integrity of roofs.

  • Tar paper played a significant role in rural housing in the past.
  • Tar paper-covered shacks provided temporary or low-cost housing in rural areas.
  • Tar paper offered basic waterproofing, protecting inhabitants from the elements.
  • The historical significance of tar paper in rural communities is undeniable.
  • Tar paper was an affordable and accessible building material in times of scarcity.
  • Tar paper remains important in modern construction for roof durability and integrity.
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Frequently Asked Questions

Will tar paper keep water out?

While tar paper does have water repellent qualities, it may not be as effective as synthetic alternatives when it comes to both durability and water shedding. Tar paper can provide some level of protection against water intrusion, but it may not be fully reliable in extreme weather conditions or for long-term use. Synthetic models, on the other hand, offer improved durability and superior water shedding capabilities, making them a more reliable choice to keep water out and ensure long-lasting protection.

How long will tar paper last uncovered?

Tar paper, when left uncovered on a roof, typically has a lifespan of around 6 to 12 months before its appearance and shape are potentially affected. While modern roofing felts are designed to withstand long-term exposure, other factors such as weather conditions and UV rays can accelerate wear and tear. Without proper protection or regular maintenance, the material’s durability and performance may be compromised over time. Therefore, it is advisable to cover the tar paper or utilize additional protective measures if aiming for a longer lifespan and optimal functionality.

Is tar paper a good moisture barrier?

Tar paper can be an effective moisture barrier, especially in regions with high humidity. While it may not serve as a vapor barrier, which can actually trap moisture, tar paper can still provide decent protection against moisture infiltration. However, its effectiveness ultimately depends on the tightness of your walls and the quality of the drywall sealing. If your walls are airtight and the drywall is well-sealed, using vapor barrier paper on fiberglass batts could be a suitable solution to further enhance moisture control.

Does felt paper absorb water?

Yes, felt paper does absorb water. Its permeability varies depending on moisture conditions, with a low absorption rate of approximately 5 perms when dry and a significantly higher rate of over 60 perms when exposed to relative humidity above 95%. In contrast, engineered wall wraps maintain a stable level of moisture permeability.

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