When you are faced with a roof repair or roof replacement, the entire process can be overwhelming and confusing. A good place to start is learning a few of the most common terms and parts of a roof.
Understanding the basic elements of your home’s roof helps you to understand all the important parts that contribute to protecting the structure of your home.
Inside the Home
We’ll dissect the roof from the inside out starting with the pieces that are installed inside the home during the construction phase.
1. Ceiling Joists
The ceiling joists are installed right after the framing is complete. They help to hold the walls of the room together and provide a structure to attach a ceiling. Ceiling joists support the load of a ceiling and ensure the walls can handle the pressure of the roof.
Rafters or trusses are placed on top of the ceiling joists and provide the underlying structure. These provide structure for the ceilings inside and the roof outside. The main difference between rafters and trusses is in both the manufacturing and the application.
Rafters are built on-site and create a vaulted ceiling and/or additional attic space. Trusses are manufactured and sometimes stronger than rafters, but they don’t leave room for a vault and must be used with flat ceilings.
3. Collar Tie/Rafter Tie
Collar ties and rafter ties perform similar, but different functions. Collar ties are installed in the top third of the structure and prevent the roof from blowing off the house in strong winds.
Rafter ties are installed at the bottom of the roof structure and prevent the weight of the roof from pancaking and pushing out the sidewalls.
Battens are the base of your roofing system. The battens sit right on top of your roof decking and provide a fixing place for the shingles or tiles.
The type, size, and spacing of roof battens depend on the roofing material to be installed.
Attic insulation is the key to keeping your home warm in the winter and cool in the summer. Insulation can be made from a variety of materials and can be a loose-fill material that is blown in to fill the space or a roll of fiberglass combined with a binder to be applied in place.
Outside of the Home:
The exterior structure starts with roof decking and finishes with the roof covering of your choice. All of these areas protect your home from the outside elements.
6. Roof Decking
The roof decking is perhaps the most important part of your roof that you’ll probably never see. Is the base layer, the foundation, the part that covers the trusses in the attic and supports the weight of your entire roofing system.
A strong roof decking (sometimes called sheathing) is critical to the strength of your entire structure.
The roof underlayment is the waterproof layer that protects your roof from soaking through and leaking into your house. Underlayment is attached with staples or plastic fixtures. There are two main types of underlayment; felt and synthetic.
- Felt Underlayment: Commonly known as “tar paper”, felt underlayment is asphalt-saturated felt that is flexible and water resistant but not completely waterproof. For sloped roofs that will shed water naturally, felt underlayment is a reliable choice.
- Synthetic Underlayment: This underlayment is a synthetic material saturated in asphalt and coated in fiberglass. This unbeatable combination is flexible, waterproof, durable, and mold-resistant while still being lightweight. For these reasons, this is the most common choice among roofing professionals.
8. Roof Covering
The roof covering is what you see when you look up on your roof.
The roof covering may be asphalt shingles, metal panels, slate or ceramic tile, or wooden shake. The roof covering adds style and protection to your home.
Flashing is an added protection measure installed around vents, chimneys, skylights/windows, dormers, and any other roof features to protect seams from moisture damage.
Flashing is typically a thin piece of metal designed to act as an additional barrier for vulnerable areas.
The Shape of Your Roof
Each of these key elements contributes to the overall shape and design of your roof.
While not all roof shapes will have every element, the unique design of each home is created by combining one or more of these pieces.
The roof ridge, or the peak, is the horizontal line where two roof planes join together.
The ridge is typically the highest point on the roof. Most roofs have at least one ridge, many have multiple ridges, and a few roof shapes have no ridge at all.
A roof valley is an area of the roof’s surface where two slopes meet and form a V.
These areas are necessary for creating space for water to run off and create a drainage system. However, they are often susceptible to damage from ongoing moisture runoff.
The abutment of your roof is an additional slope that connects to the side of the house and extends to cover a roof or porch.
An eave is a portion of the roof that extends farther than the roof deck. Eaves give the home a particular style and protect the siding and foundation from moisture.
The protruding eaves allow snow and rain to fall from the roof straight to the ground, protecting your home from unwanted moisture.
The soffit of your roof is the underside of the eaves.
If your home doesn’t have eaves, it won’t have soffits either. Soffits finish the eaves and can be painted with a matching or contrasting color to add visual interest.
15. Fascia Board
The fascia is like the trim along the edge of your roofline. The main job of the fascia is to protect moisture from entering the roof. For a tile or slate roof, the fascia also supports the bottom row of roofing materials. Fascia is typically made of PVC and it gives your roof a finished look.
These are elements added to your roof for either essential functionality or design aesthetics.
The chimney is essential to any fireplace in the home. As you snuggle up by the fire, the chimney works to remove dangerous gasses, like carbon dioxide, from the air. Any heat source that burns fuel (gas, coal, wood, etc.) requires a chimney.
A skylight is essentially a window on your roof. Skylights add both light and ventilation to your space. They can be a beautiful addition to vaulted ceilings to make a unique architectural statement.
18. Gutter & Downspout
Gutters provide a drainage system for your roof. They are designed to direct rainwater away from the siding and foundation and pour it into a downspout and away from the home.
Roof ventilation is a crucial part of any structure. The ventilation in your roof is a system of intake and exhaust vents to circulate the air inside the attic. It is important to keep the air in the attic dry and comfortable.
Without proper ventilation, hot air and moisture can get trapped in the attic and cause mold, mildew, and a variety of problems for your property.
Understanding Your Roof’s Anatomy
Having a foundational knowledge of the parts of a roof can help you to design, create, and protect your home’s most important asset.
Understanding how your roof’s structure works together, what areas are susceptible to damage, and how to support the needs of your roof can help you to be a proactive and informed homeowner.
If you need any work done on your roof, give us a call!