Understanding the parts of a roof can help you discern what goes into roof repairs and installations. This guide to parts of a roof will quickly tell you what you need to know.
Structural Framework
The structure provides support for the rest of the roof’s components. It consists of:
- Rafters: These beams form the slope, running diagonally from the peak to the eaves.
- Trusses: These tough, triangular frames support heavy loads. They’re a common alternative to rafters.
- Ceiling joints: Horizontal cross beams are used to tie the ceiling together and secure it to the structure’s walls.
Decking
Layered above and fastened to the rafters or trusses, decking offers a solid flat surface for the rest of the roof. It’s generally plywood or oriented strand board (OSB).
Underlayment
Wood on its own doesn’t provide very good water or moisture resistance. That’s why a primary moisture defense is placed between the decking and other roof materials. There are several options:
- Felt paper: Organic or fiberglass substrate offers strong water-resistance. Felt paper is attached with staples, wind strips or plastic caps.
- Synthetic underlayment: Although lighter, synthetic underlayment is tougher and more water-resistant than felt. It’s often saturated with asphalt and fiberglass for added tear-resistance. It also offers vapor protection from external sources.
- Ice and water shield: Primarily meant for high-risk areas or sections prone to leakage, these waterproof, self-sealing membranes are made of a rubberized asphalt compound. They can be used in conjunction with other underlayment options.
Covering
Roof coverings are placed above the underlayment and moisture barrier. For example:
- Shingles: Shingles come in asphalt, wood and more styles.
- Tiles: Tiles are heavy, durable, weather-resistant and long-lasting.
- Metal: A metal roof is built using metals like steel, aluminum, copper and zinc.
With shingled roofs, starter shingles are installed along the edges to achieve a stronger seal and wind-resistant foundation. They are narrower than traditional shingles with preapplied adhesive for unique applications.
Flashing
Roof flashing is generally made of solid metal or alloys. It moves water away from seams, joints and penetrations to reduce minor leaks. Flashing examples include:
- Chimney flashing: Flashing helps seal the sticks, pipes and other vulnerable areas like skylights.
- Valley flashing: Where two slopes meet, there is a natural seam creating a “V” shape. Flashing is used to prevent water from entering between these valleys.
- Stepped flashing: Step flashing, in an “L” shape, is installed piece by piece, stepping up the area. Water flows down each piece and off the roof.
- Apron flashing: Apron flashing is draped over the segments where a roof meets dormers or protrusions, or where the roof deck meets the exterior walls.
- Ridge capping: An advanced form of flashing, ridge capping is installed where the two sides of a pitched roof meet. It covers other exposed components, giving the roof a more professional, finished appearance while protecting it from moisture.
Edges
Around the edges, you’ll find multiple components meant to protect the sides and seams of the roof materials:
- Drip edge: Metal flashing placed on the edges of the roof helps direct water away from the home.
- Fascia: These vertical boards run along the roofline to cover the rafters or trusses and provide a finished look.
- Eaves: These stick out over the walls to protect from precipitation.
- Soffit: This protective yet ventilated board covers the underside of the eaves while allowing air into the attic.
If you ever need to replace wood under roof overhangs, you may need to remove some of these components. This would be necessary if there is rotting or severe decay. The task is best left to professionals.
Roof and Attic Ventilation
Attic ventilation helps prevent heat buildup. For example:
- Ridge vents: Create a continuous and reliable vent along the roof peak.
- Soffit vents: Soffit vents are built into the pieces of soffit and installed above the eaves.
- Gable vents: Gable vents can be decorative and functional, reducing temperatures and preventing moisture buildup.
- Turbine and hood vents: These vents are designed to work like chimneys or traditional exhausts.
The parts work together to cool the attic and prevent mold and moisture buildup. Air is drawn in through the soffit vents, rising and exiting out the ridge vents or additional vents, and is often supplemented by the side-mounted gable vents.
Rely on the Pros for Roof Work
Many elements go into a roof, so when it comes time for repairs or replacements, you want to work with reliable professionals. Equity Builders Roofing has served Indiana communities for more than three decades, and we can help your home or business.
Contact an experienced roofer today for more information!