Roof systems: every parts you need to know about roofing

A roof system refers to the combination of various components and materials that work
together to protect a building from the elements and ensure its structural integrity. It is
essentially the outermost layer of a building’s envelope, designed primarily to shield it
from rain, snow, wind, and other weather conditions. A well-designed and properly
installed roof system is essential for preventing water damage, maintaining proper
ventilation, and prolonging the lifespan of the building. It consists of several key
elements. Each of these components plays a crucial role in creating a watertight barrier
and providing adequate insulation and ventilation for the building. Roof systems can vary
in their design, materials, and installation methods, depending on the specific
requirements of the building and the climate in which it is located.

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Disclaimer: While the information provided in this article is intended to provide a general
overview of roof systems, it should not be used as a substitute for professional advice.
For specific advice regarding your building project, we recommend consulting with a
licensed and experienced roofing contractor. Advance Roofing LLC has been proudly
serving the Spokane, WA area for many years with the highest standard of quality roofing
solutions and we are always happy to help.

Types of Roof Systems

There are several types of roof systems, each determined by factors such as the
architectural style of the home, the type of roofing material used, and the pitch of the roof
structure. Here are some of the most common types:

  1. Sloped Roofs: Sloped roofs are the most popular type, seen in a variety of architectural
    styles. They provide excellent water drainage and are typically covered with materials like
    asphalt shingles, metal roofing, or wooden boards.
  2. Flat Roofs: Flat roofs are commonly found in commercial buildings but are also used in
    some residential properties. They require special attention to proper drainage to prevent
    water damage.
  3. Gable Roofs: Gable roofs are characterized by their triangular shape formed by two
    sloping sides meeting at a ridge. They are popular due to their simple design and
    excellent water drainage.
  4. Mansard Roofs: Mansard roofs have two slopes on each side with the lower slope
    being steeper than the upper slope. They offer additional living space in the form of a full
    attic or a room with a sloping ceiling.
  5. Gambrel Roofs: Gambrel roofs have two slopes on each side, with the lower slope
    being steeper than the upper slope, similar to mansard roofs. Gambrel roofs are
    commonly seen in barns and provide ample space in the attic.

The type of roof system you choose will depend on the architectural style and your
specific needs. Consulting with a roofing professional can help you determine the most
suitable option for your home or building.

Components of a Roof System

A roof system is comprised of several components that work together to provide
protection, insulation, and proper ventilation for a home or building. Understanding these
components is essential for ensuring a durable and long-lasting roof.

  • Roof Deck: The roof deck is the foundation of the roof system and
    serves as the structural base to which all other components are
    attached. It is typically made of wood or metal and provides support for
    the roof covering.
  • Roof Underlayment: The underlayment is a layer of protection placed on
    top of the roof deck. It acts as a waterproof barrier, preventing water
    from penetrating the roof and causing damage. Synthetic underlayment
    and asphalt felt are commonly used materials.
  • Roofing Material: The roofing material is the outermost layer of the roof
    system and is responsible for protecting against weather elements such
    as rain, snow, and sunlight. Common roofing materials include asphalt
    shingles, metal panels, clay or concrete tiles, and slate.
  • Flashing: Flashing is a weatherproofing material that is used in areas
    where the roof meets a vertical surface, such as chimneys, skylights,
    and vent pipes. It helps to prevent water from seeping into the joints and
    causing leaks.
  • Ventilation: Proper ventilation is crucial for maintaining the health of a
    roof system. It allows for the exchange of air, preventing moisture
    buildup and heat accumulation, which can lead to the rotting of wood
    and the deterioration of the roof structure. Soffit vents, ridge vents, and
    roof vents are common ventilation components.
  • Roof Edge: The roof edge, also known as the eave, is the perimeter of the
    roof. It is typically finished with a fascia board, which provides support
    and a clean look to the roof system.

By understanding the components of a roof system, homeowners and roofing
professionals can make informed decisions about maintenance, repairs, and
replacement, ensuring the longevity and functionality of the roof.

A well-maintained and properly functioning roof adds aesthetic appeal to your home as
well as peace of mind knowing that you've taken the steps to protect it from damage due
to weather or other issues.

Roof Decking

Roof decking is an essential component of a roof system as it serves as the foundation
for the entire structure. It provides stability and support for the roof covering and other
components. There are two main types of roof decking: plank decking and sheet decking.

Plank decking is made up of individual wooden boards that are placed side by side to
form a solid base. The sizes and thicknesses of plank decking can vary depending on the
specific requirements of the roof system. Common sizes include 2×6, 2×8, and 3×6, with
thicknesses ranging from 1 inch to 2 inches.

Sheet decking, such as OSB (oriented strand board) or plywood, is made of large sheets
of engineered wood. These sheets are typically 4 feet by 8 feet and come in different
thicknesses, such as 1/2 inch or 5/8 inch.

It is important to note that if the roof decking is rotten or damaged, it will need to be
replaced before installing a new roof. Rotten or weakened decking can compromise the
structural integrity of the entire roof system and may lead to further damage. Therefore,
proper inspection and maintenance of the roof decking are crucial for the longevity and
performance of the roof.

Underlayment/Weatherproofing Layer

The underlayment, also known as the weatherproofing layer, is a crucial component of a
roof system. Its primary purpose is to provide an extra layer of protection against leaks
and harsh weather conditions.

The underlayment acts as a barrier between the roof deck and the shingles or other
roofing materials. It helps to prevent water infiltration, protecting the structure from
potential water damage. It also acts as a shield against ice and snow, reducing the risk of
leaks and ice dams.

There are two main types of underlayment: felt and synthetic.

  • Felt underlayment is made from organic materials, typically asphalt-
    saturated cellulose fibers. It is cost-effective and has been used in roofing for many years.

  • Synthetic underlayment, on the other hand, is made from synthetic
    materials, such as polyethylene or polypropylene. It offers superior
    durability, resistance to tears, and better resistance to UV rays.

Additionally, underlay membranes are sometimes used in conjunction with underlayment.
These membranes provide an additional layer of protection and can further extend the
lifespan of the shingles and decking. Underlay membranes are typically made from
materials like synthetic rubber or ethylene propylene diene monomer (EPDM).


Shingles and tiles are an integral part of any roofing system and serve as the outermost
layer of protection for your home. There are various types of shingles and tiles available,
each with its own unique characteristics and advantages.

One of the most commonly used roofing materials for residential properties in North
America is asphalt shingles. These shingles are lightweight, cost-effective, and easy to
install. They come in three main styles: traditional or 3-tab shingles, laminate or
architectural shingles, and designer shingles. Traditional shingles have a clean, uniform
look, while laminate shingles offer a more dimensional appearance. Designer shingles
mimic the look of natural materials like wood or slate, adding a touch of elegance to your

In addition to the main shingles, there are starter strip shingles and hip and ridge cap
shingles. Starter strip shingles are installed along the eaves and rake edges of the roof to provide a secure base for the rest of the shingles. Hip and ridge cap shingles are used to
cover the ridges and hips of the roof, providing a finished and more aesthetically pleasing

When choosing shingles, you may also consider options with solar-reflective and thermal-
emissive properties. These shingles help to reduce heat absorption and keep your home

cooler, resulting in potential energy savings. Alternatively, you can opt for shingles that
resemble slate, offering a luxurious look without the high cost and weight associated with
real slate.

Roof planes form the shape and angle of a roof to protect it from water damage.

Flashing and Sealants

Flashing and sealants play a crucial role in the overall effectiveness of a roof system by
preventing water infiltration at vulnerable areas.

Flashing is typically made of aluminum or galvanized steel and is installed at areas such
as chimney joints and skylights. Its purpose is to create a barrier that redirects water
away from these vulnerable areas, preventing leaks and water damage. Without proper
flashing, water can seep into the roof structure and lead to costly repairs and mold

Sealants, on the other hand, are used to create a watertight seal between different roofing
components. Common types of sealants used in roof systems include caulk and roofing
cement. These materials are applied to areas where there may be small gaps or joints,
ensuring that water cannot penetrate through. By creating a tight seal, sealants help to
maintain the integrity of the roof and prevent water infiltration.

Ridge Vents and Soffit Vents

Ridge vents and soffit vents are essential components in a roof system that play a crucial
role in maintaining proper air circulation and preserving the integrity of the roof structure.

Ridge vents are installed at the peak of the roof, running along the ridge line. Their
purpose is to allow hot air and moisture to escape from the attic space. By creating a
continuous ventilation pathway, ridge vents ensure that stale air is expelled from the attic,
preventing heat and moisture buildup. This helps to regulate the temperature and
humidity levels, reducing the risk of mold growth, ice dams, and deterioration of the roof

Soffit vents, on the other hand, are installed under the eaves of the roof. They allow fresh
air to enter the attic, replacing the hot air that is being expelled through the ridge vents.
Soffit vents work in conjunction with ridge vents, promoting the flow of air from the soffit
to the ridge, creating a balanced and continuous ventilation system. This prevents
condensation, moisture buildup, and the damaging effects they can have on the roof

Having a well-ventilated attic has numerous benefits. It helps to extend the lifespan of the
roof by reducing excessive moisture and heat, which can cause premature aging and
deterioration of roofing materials. Proper attic ventilation also helps to regulate the
temperature inside the home, reducing the strain on HVAC systems and resulting in
energy savings. Additionally, it helps to prevent the formation of ice dams during winter
months, which can lead to costly damage and water leaks.

Advantages of Having a Well-Constructed Roof System

Having a well-constructed roof system comes with numerous advantages.

  • One of the key benefits is the prevention of water damage. A properly
    designed and installed roof system ensures that water is effectively
    channeled away from the structure, protecting it from leaks and
    potential structural damage.
  • Additionally, a well-constructed roof system provides excellent
    insulation, helping to regulate the temperature inside the building and
    reducing energy consumption. This can result in significant energy
    savings over time.
  • Furthermore, a durable roof system can withstand harsh weather
    conditions, such as strong winds and heavy snow, providing peace of
    mind and protecting the property from damage.

Overall, investing in a well-constructed roof system is crucial for maintaining the integrity
of a building and ensuring its long-term durability.

 Repairs can range from patching and caulking to replacing shingles or sections of a

Increased Durability and Longer Lifespan

A well-constructed roof system can significantly increase the durability and lifespan of a
roof. By utilizing quality materials and proper installation techniques, a roof can withstand
various weather conditions and protect your home for many years.

The choice of roofing materials is crucial in determining the lifespan of a roof.

  • Asphalt shingles, one of the most popular types of roofing material,
    typically have a lifespan of 15 to 30 years.
  • Metal roofing, on the other hand, can last anywhere from 30 to 70 years,
    while slate or tile roofs have an impressive lifespan of 50 to 100 years.

To further enhance the longevity of a roof, many roofing companies offer extended
warranties. These warranties provide additional protection for the roof and can extend its
lifespan even further. However, it is important to address any underlying issues before
installing new shingles or roofing material. This includes fixing any water damage,
ensuring proper ventilation, and addressing any structural issues.

By investing in a well-constructed roof system and using durable roofing materials,
homeowners can enjoy a longer lifespan for their roof. Extended warranties and
addressing underlying issues can also contribute to the overall durability and longevity of
the roof, providing added peace of mind for homeowners.

Prevention of Water Damage and leaks

Prevention measures play a crucial role in avoiding water damage and leaks in a roof
system. By addressing potential vulnerabilities, homeowners can ensure the longevity and effectiveness of their roofs. One key tool in this prevention arsenal is the use of ice
and water guards and protectors.

  • Ice and water guards are essential components that provide an extra
    layer of protection against ice dams, wind-driven rain, and other
    elements. These guards are typically installed along the roof’s eaves and
    in vulnerable areas such as valleys and roof edges. The guards create a
    seal that prevents water from seeping into the roof structure, reducing
    the risk of leaks and costly repairs.
  • In addition to ice and water guards, proper flashing installation is vital in
    preventing water damage. This flashing is placed around chimneys,
    skylights, vent pipes, and other roof penetrations to help redirect water
    away from vulnerable areas. By ensuring that all flashing is properly
    installed and sealed, homeowners can minimize the risk of water
  • Furthermore, addressing proper ventilation is essential in maximizing the
    effectiveness of these prevention measures. Adequate ventilation helps
    to regulate temperature and moisture levels within the roof system,
    reducing the risk of condensation and the formation of ice dams.

By implementing these prevention measures, homeowners can significantly reduce the
risk of water damage and leaks in their roof systems. Regular inspections and
maintenance by a roofing professional are also crucial in identifying and addressing any
potential issues before they escalate.

Proper Ventilation to Reduce Heat Buildup in Home or Building

Proper ventilation is crucial when it comes to reducing heat buildup in a home or building.
Without adequate airflow, excess heat can become trapped in the attic or roof space,
causing temperatures to soar and creating a less comfortable living environment. Heat
buildup can also have a detrimental impact on the roof itself.

Inadequate airflow and ventilation can lead to moisture-related issues that can affect the
lifespan of the roof. Without proper ventilation, moisture can become trapped, leading to
the growth of mold and mildew. This not only poses a health risk but can also weaken the
structure of the roof. Moisture can cause the roof decking and sheathing to deteriorate,
shortening the lifespan of the entire roof system.

Several factors affect air circulation and the effectiveness of ventilation. The presence of
insulation, vapor barriers, and open vented spaces all play a role. Insufficient insulation or
a poorly installed vapor barrier can impede airflow and prevent hot air from escaping.
Additionally, the gap between the insulation and roof sheathing should allow for proper
airflow to prevent heat buildup.

To ensure proper ventilation and reduce heat buildup, homeowners and building owners
should consult with a roofing professional. They can assess the specific needs of the roof
system and recommend the appropriate ventilation solutions. By addressing ventilation issues, it is possible to create a more comfortable living space and extend the lifespan of
the roof.

Factors to Consider When Installing a Roof System

Installing a roof system involves careful consideration of various factors to ensure its
durability and effectiveness. One crucial aspect is proper ventilation and airflow. The type
of roofing material, such as asphalt shingles or metal roofing, needs to be chosen based
on the specific requirements of the project and the climate in the area. The slope of the
roof and the presence of roof valleys and edges also need to be taken into account.
Finally, the expertise and experience of the roofing professional or contractor are vital for a successful installation. By considering these factors, homeowners can ensure a long-
lasting and efficient roof system.

Investing in a high-quality roof system with the necessary drainage components can
protect your investment for years to come.

Climate Conditions in Your Area

When it comes to installing a roof system, it is crucial to consider the climate conditions
in your area. These considerations include fire rating requirements, ventilation needs, and
compatibility with the slope of the roof.

  • Fire rating is important for areas prone to wildfires or where fire-resistant
    materials are required by local building codes. Choosing a roof system
    with a high fire rating can help protect your home from potential fire
  • Proper ventilation is essential to prevent moisture buildup, which can
    lead to mold growth and structural damage. In hot and humid climates,
    sufficient ventilation helps expel excess heat and humidity, keeping your
    home comfortable and preventing damage to the roof and attic area.
  • The slope of the roof is another critical factor. Steep-sloped roofs are
    better suited for areas with heavy rainfall or snowfall, as the steeper
    angle allows for better water drainage. Flat or low-sloped roofs may be
    more suitable for dry climates where precipitation is minimal.

Considering these climate conditions is vital for the durability and longevity of your roof.
A roof system that meets fire rating requirements, provides proper ventilation, and is
compatible with the slope of your roof will be better equipped to withstand the challenges
posed by your local climate.

Cost-effectiveness of Different Materials

When it comes to choosing a roofing material, cost-effectiveness is an important factor
to consider. Different materials come with varying levels of durability and installation
difficulty, which can impact the overall cost of a roof.

  • Asphalt shingles are a popular and cost-effective option, offering a good
    balance between affordability and durability. They are relatively easy to
    install, making them a budget-friendly choice for many homeowners.
  • Cedar shingles, on the other hand, provide a natural and rustic
    appearance but tend to be more expensive than asphalt. However, they
    have a longer lifespan, making them a cost-effective choice in the long
  • Metal roofing is another highly durable option, lasting for decades with
    minimal maintenance. While it may have a higher upfront cost, its
    longevity makes it a worthwhile investment.
  • Slate roofs are known for their beauty and exceptional durability, with a
    lifespan of up to 100 years. Although they come with a higher price tag,

    their longevity and low maintenance requirements make them cost-
    effective over time.

It’s important to note that the cost of a roof can vary depending on the region and the
material chosen. Labor costs, building codes, and climate considerations can all impact
the overall cost.


In conclusion, understanding the different parts of a roof system is crucial in protecting
our homes from water damage and other issues. By investing in a high-quality roof
system that includes the necessary drainage components and ventilation features,
homeowners can protect their investment and prevent costly water damage. It is
important to consult with a professional roofing contractor to assess the specific needs
of your roof and ensure proper installation.

Remember, a well-maintained and properly functioning roof not only enhances the
aesthetic appeal of a home but also provides peace of mind knowing that you have taken
the necessary steps to protect your property for years to come.

Everything You Need to Know About Roof Systems: FAQs

What are roof planes?

Roof planes refer to the inclined sections of a roof that form its shape and angle. Most roofs have two or more planes, with the bottom plane typically being more shallow than the top plane.

How much will my roofing project cost?

The total cost of a roofing project will vary depending on several factors, such as the size of your home, the type of material used, and any additional features you choose to install. As a general rule of thumb, expect to pay $3-$6 per square foot for most materials.

What is a roof ridge?

A roof ridge is the highest point on a sloped roof where two opposing slopes meet. It is usually covered in metal flashing or other materials to prevent water from entering through this joint.

How can I tell if I have a roof leak?

Signs of a potential roof leak include discoloration on ceilings or walls, musty smells in your attic, visible signs of water damage or mold growth, and standing water or dampness near chimneys or vents.

How do I repair my leaking roof?

Depending on the severity of the leak, repairs may range from simple patching and caulking to replacing shingles or even an entire section of your roof. If you are unsure how to best address your specific issue, it is best to consult with an experienced professional for assistance.