Basics of Roofing Systems

Roofing systems
Roofing Systems -

Welcome to Section 2 of our comprehensive guide on roofing systems. In this section, we look into the fascinating world of roofing, offering a detailed exploration of the various roofing systems, their essential components, and the materials commonly used in their construction. 


Whether you’re a homeowner seeking to understand the intricacies of your roof or a builder looking to deepen your knowledge, this section is tailored to provide you with a thorough understanding of what goes into protecting and maintaining the structure of a building.


Roofing is more than just an external covering; it’s a sophisticated architectural element that plays a crucial role in safeguarding a home from the elements. We’ll guide you through the anatomy of a roof, including rafters and trusses, the skeletal framework, and the sheathing that forms the base layer. You’ll learn about the importance of underlayment in waterproofing and the various components like ridges, eaves, rakes, valleys, and hips that contribute to a roof’s functionality and aesthetic. 



Additionally, we’ll discuss the significance of roof slopes in water shedding and introduce you to different roof shapes, each with unique benefits and visual appeal. From flat and gabled roofs to hip and mansard styles, this section covers it all, complete with illustrative references to enhance your understanding. 

Join us as we embark on this educational journey into the world of roofing systems.


Anatomy of a Roof:

Understanding the anatomy of a roof is crucial for homeowners and builders alike. The roof is more than just an external covering; it is a complex system designed to protect, insulate, and maintain the structure of a home.

Rafters and Trusses

These are the skeletal framework of the roof. Rafters are individual beams that run from the peak of the roof to the walls of the house, while trusses are pre-made triangular units that support the roof.

Rafter X Truss -
Roof Sheathing -


This is the layer of boards or panels fastened to the rafters or trusses to cover a house or building.


A protective layer placed between the sheathing and the roof covering, typically made of waterproof or water-resistant materials.

Roof Underlayment -

Each component of a roof plays a specific role:

Ridge: The highest point of the roof, where two slopes meet.

Eave: The part of the roof that extends beyond the house’s walls.

Rake: The inclined edge of a gabled roof at the end wall of the house.

Valley: The internal angle formed by the intersection of two sloping roof planes.

Hip: The external angle at the junction of two sides of a roof whose supporting walls adjoin.

Slope and its significance in water shedding

The slope of a roof is pivotal in its design, affecting how well water is shed and how the roof withstands weather conditions. A well-angled roof can prevent water accumulation, which is vital for the longevity of roofing materials.

Different roof shapes offer various benefits and aesthetic appeals:

  • Flat Roofs: Often found in arid climates, they are easier to construct and can be used as living spaces or for placing HVAC units.
  • Gabled Roofs: Characterized by their triangular shape, they easily shed water and snow and provide more space for an attic or vaulted ceilings.
  • Hip Roofs: With slopes on all four sides, these roofs are stable and provide excellent resistance to wind.
  • Gambrel Roofs: The gambrel has two different slopes on just two sides, offering extra living space in the attic.
  • Mansard Roofs: A mansard roof is a four-sided gambrel-style roof characterized by two slopes on each side, with the lower slope being significantly steeper than the upper, often punctuated with dormer windows to create additional living space under the roof. This design not only enhances the aesthetic appeal of a building but also maximizes the usable space within the attic area.
Roof Types
Roof Types -
The selection of materials for sheathing, underlayment, and external roofing is critical in constructing a durable and weather-resistant roof. 

Here’s a list of common materials used for each component. You can check Section 4 of our Roofing Guide for more info on materials. 

Sheathing Materials

Sheathing, also known as decking, provides a flat plane for other roofing materials and a nailing surface for the shingles or roofing materials.
  • Plywood
  • Oriented Strand Board (OSB)

Underlayment Materials

Underlayment is a layer of material placed over the roof deck before the installation of the roof covering. It acts as a secondary barrier against water penetration.
  • Felt Paper (Tar Paper)
  • Synthetic Underlayment
  • Rubberized Asphalt

External Roofing Materials

The external roofing material is the outermost layer of the roof, exposed to the environment. It is the first line of defense against the elements.
  • Asphalt Shingles
  • Metal Roofing (Steel, Aluminum, Copper)
  • Wood Shingles and Shakes
  • Clay and Concrete Tiles
  • Slate Tiles
  • Synthetic Roofing (Rubber, Plastic, Polymer)
  • Green Roofing
  • Solar Roof Tiles

When choosing materials for each layer of the roof, it’s important to consider:

  • the local climate
  • the design of the roof
  • the weight-bearing capacity of the existing structure
  • the long-term maintenance requirements

Each material comes with its own set of benefits and limitations, and the right choice will depend on a balance of cost, durability, aesthetic preference, and environmental conditions.


Let VendorSmart℠ source vendors, compile bids and build your board packet

© 2023 VendorSmart. All Rights Reserved.