8 Important Parts of Your Roof

Your roof is pretty complex and considered one of the most critical components of the home. With so many different layers and features, it can be daunting to figure out what they all do. Understanding the roofing system is essential to staying on top of repairs and militance to avoid costly repairs down the road.

What is Roof Sheathing or Decking?

Roof sheathing, or decking, is the supportive plywood layer underneath your shingles. Roof decking is essential to the structure of a home as it supports the roof and attaches to the rafter or trusses. Most decking is made of plywood, or a plywood composite known as Oriented Strand Board (OBS) and is composed of intertwined wood strands held together by resin. Plywood is more expensive than OBS but is much denser and provides more protection from moisture.

If your decking is moldy or damaged, it can cause severe structural issues. Most commonly, these issues are caused by poor ventilation and insufficient insulation. Water is the number one enemy when it comes to your roof. Since decking is made from wood, its highly susceptible to mold, rotting, and water damage. Moldy decking can cause sagging and ventilation issues in the attic, promoting more moisture and compounding the damaging effects.

What You Should Know About Roof Flashing

Roof flashing is a thin metal material that roofers will install to direct water away from areas where water will seep in and cause damage. The flashing is installed under the shingles and leads the water to a different location.

Roofers will install flashing over a layer of Ice and Water barrier in these most common areas:

• Sidewalls and front walls – the surface that joins the roof to the wall.
• Valleys –the incline where two roof sections join.
• Roof protrusions – skylights, chimneys, and vents.
• Roof edges – the eaves and rakes.

Roofers will use aluminum, steel, or copper, although the most commonly used is steel. If homes didn’t have flashing, water could get in where the decking meets sidewalls and cause molding.

How Important Are The Gutters?

The gutters are essential to the proper function and protection of the roofing system. The gutters are the channels that run along the roof's edges that catch rainwater and the downspouts carry it away from the foundation of the building. Without a gutter system, water will collect around the base of the home and soak in, weakening the foundation and cause severe structural damage. If you have a basement, it will also be more prone to flooding.

A properly installed gutter system will protect from many of these issues if appropriately maintained. Leaves, branches, and other debris can block and plug your gutters, preventing them from draining and causing water to stagnate.

Roofing Underlayment: What Is It For?

The roofing underlayment sits between the decking and shingles. Since singles overlap, they are particularly vulnerable to wind or rain damage, so the underlayment is installed to add a layer of protection from the wind, rain, and snow. Underlayment comes in three primary materials. This includes felt, synthetic felt, and Ice and Water.

• Felt Underlayment: Sometimes referred to as “felt paper” or “tar paper,” this is one of the oldest types of underlayment. It’s made of organic fibers and sometimes fiberglass fibers which are then saturated with asphalt to make it water-resistant. One of the main advantages of using this kind of underlayment is that it comes in different sizes and thicknesses, as well as varying resistance to weather damage. Felt underlayment is typically less expensive than other materials while providing a solid barrier from the elements.
• Synthetic Underlayment: Synthetic underlayment, or “non-bitumen underlayment,” is a plastic, synthetic compound. This has been a popular option for contractors within the past 10-15 years as it has a very high tear strength compared to felt. It is also suitable for extended UV and moisture exposure if there’s a lapse between installing the underlayment and shingles. Owens Corning also found it was up to four times lighter in some cases.
• Ice & Water: Ice & Water underlayment contains asphalt and rubber polymers, making it water-resistant. Additionally, it has a peel-and-stick back to create a waterproof seal between the underlayment and decking. This underlayment is a code requirement for many northern states over the eaves and areas prone to ice dams. Many contractors and manufacturers will require the installation of Ice and Water around the eaves, roof valleys, vents, chimneys, and skylights.

Your Roof Vent System: The Basics

Roofing ventilation allows airflow through the attic space and keeps it from overheating during the summer and from warming during the winter. The roofing ventilation is a system of intake and exhaust vents to circulate the air and match the temperature and humidity levels of the attic to the outdoors. Good ventilation will extend the life of a roof, reduce energy costs, and prevent damage to the shingles, decking, and framing.

Insufficient ventilation will lead to a host of issues. During the summer months, condensation will develop on the frame and decking, resulting in mold and mildew growth. During the winter months, condensation from the warm air escaping your home will meet the cold frame and decking, causing the moisture to freeze. As it warms up again, the ice melts, causing ceiling damage.

Bad ventilation can also lead to ice damming during the wintertime. A poorly ventilated attic will get warm enough to melt the sitting snow. As the water runs to the gutters, it freezes again, causing water to pool behind it. Over time, this freezing and melting process causes water to penetrate the shingle and underlayment. The water then enters the home through the gaps in the decking, and where the roof meets the sidewalls, entering water will damage the ceiling and frame.

What are Rafters on a Roof?

Rafters are the main support beams of your roofing system and are an essential component of your home. Most homes will have wooden rafters, though many larger structures will use metal for extra durability. Wooden rafters are very cost-effective and lightweight and aid in distributing the weight evenly across the roof.

Rafters are not the same as Trusses

Rafters Rafters are built out of 2” by 6” or greater Douglass Fir or engineered wood materials. Rafters have been the traditional method of framing roof and attic spaces into the mid ’80s. Contractors would use 2" × 6" and greater materials depending on the spans of ceiling rafters to connect interior to exterior walls. Also, a method used to create traditional ceilings and can also provide the traditional "attic" of years past.

Trusses Structurally Engineered Trusses are the most common form of roof systems today. With modern-day engineering, these trusses can create traditional ceilings or more complex vaulted ceilings. These trusses range from 2" x 4" material or greater depending on the complexity of the truss design. Trusses provide a contractor the ability to create spaces in the attic that allows a roof system to perform correctly when installed properly.

How Important Is The Roofing Insulation?

Insulation is crucial to temperature management. It helps keep the building at the desired temperature and prevent heat loss.

In the Midwest or cooler climates, contractors will typically use fiberglass insulation (“rolled” or “blown” insulation). Another option is spray foam, but it can also cause moisture problems if not installed correctly.

During the wintertime, this prevents heat from escaping into the attic, causing higher power bills and ice damming. Many homeowners may be surprised to learn that at least 30% of their heat is lost through the roof. Proper insulation is critical in ensuring extra warmth isn’t lost.

During the summertime, properly installed insulation will prevent your home from getting excessively hot, causing your cooling system to work harder. Our experts highly recommend an inspection of the home to determine the proper insulation required.

What is an Asphalt Shingle Roof?

The final part of the roof system is the covering (or shingles). Shingles are flat and rectangular and are laid from the bottom to the top and overlap the ones below. They can be made from many materials like cement, flagstone, asphalt, plastic, or metal. The materials used can increase the home's value and curb appeal. Most homes will use asphalt shingles because they are relatively inexpensive, durable, and can last for a decade or more, some lasting from 10 to 50 years, depending on the quality of the shingles, before needing to be replaced.

There’s no shortage of options when it comes to roof coverings, and the type used depends on personal choice and the style a homeowner wants. If you’re curious about the different costs depending on the size of your roof and material, use our handy tool here.

Catching Problems and How to Fix Them

There are several things you can keep an eye out for so that you can prevent problems before they get too costly. Have regularly scheduled property inspections done. We recommend every one to two years. Create a to-do list from these inspections, and between, complete the recommended work.

If you’ve experienced a storm recently, have a professional evaluate your roof. Storms often cause various types of damage to property. Wind damage is very common, which can happen with the smallest of storms. Hail damage is not as common but can cause damage to both new and old roofs. Depending on the condition and age of your roof, even the smallest of hail events can affect its total lifespan. Damages from a storm event can result in missing, torn, or creased shingles. Hail can cause granular loss, which exposes the undermatting of the shingle and cause bruising. Hail will also cause indentations and the cracking or breaking of the undermatting of a shingle. In extreme cases, wind or flying debris can impact a roof which causes structural damage to the roofing system.

Internally, look for damage where your walls connect to the roof or any areas of the ceiling that appear to have water markings on areas that contain ventilation systems such as bathroom or laundry room vents. We recommend having a professional inspection completed for prevention and repair solutions. Any damage to your shingles or roofing system will cause long-term damage and can be very costly to repair and devalue your home.

Each of the roofing components work together, giving you a safe space to live. If you begin to notice issues or want a more in-depth inspection, we offer free property evaluation of your exterior, attic, and roof evaluations.

Schedule a free evaluation.