Real Estate

Roof Replacement Terms and Definitions

Unfortunately, at this point in the history of building construction, we have yet to develop a roofing system that will last forever. Therefore, it is very likely that each of us will have to deal with a roof replacement.

After all, the roof is the most important structural component of any building. Without a quality waterproof roof, all other components of a building will be destroyed in no time. Paint, drywall, framing, and flooring simply aren’t designed to stand up to Mother Nature. Indoor spaces and people need protection from the elements.

Below are some roofing terms that may be helpful during the decision-making process:

Square – A unit of measure commonly used in roofing and siding that equals 10 feet by 10 feet or 100 square feet (1 square equals 100 square feet). Most roofing material is sold by the square, and roofers generally calculate costs and price based on the total number of squares.

Sheathing or Sheeting: The flat layer of material attached to the roof joists. Many old houses and buildings have wooden plank roofing. Most modern residential buildings have plywood or oriented strand board (OSB) decks that are manufactured in 4-foot x 8-foot sheets (sometimes called sheets). The most common roof deck thickness used today is 7/16″. The base and shingles are attached to the roof deck.

Asphalt Shingles – Organic-based shingles that were discontinued in 2006 due to poor performance and many class action laws. The term asphalt shingle is still often used today as a misstatement. Post-2006 shingles are referred to by many roofers as asphalt shingles, where the correct technical term is actually composition shingle.

Composition Shingle – Modern shingles made from a mixture of asphalt and fiberglass. The asphalt/fiberglass body of the shingle is covered with a protective granular wear layer.

Granular Wear Layer – The ceramic topcoat of a composition shingle provides stiffness (protection from hail, debris, and punctures), UV protection, and also provides color.

Architectural/Laminated/Dimensional Shingles – All terms refer to popular modern shingles made from multiple layers of asphalt/fiberglass material (laminated) that provide added strength, longevity, and a shake-like appearance.

Underlayment – ​​The layer of material that is applied to the roof deck before the shingles are installed. The most common underlayment is felt (tar) paper in 15 or 30 pound options. There are many newer synthetic products available that are made with waterproof/breathable material (similar to house wrap). Synthetic underlayment has been proven to have longevity and performance advantages over traditional roofing felt.

Ice and Water Barrier or Weather Barrier – An underlayment manufactured with adhesive on one side and used to protect roof eaves and valleys from ice dams and standing water. Installing an ice and water barrier is a critical step in preventing water and/or ice from collecting in gutters and passing under the shingles onto the roof deck. Most municipal building codes require that a minimum of the first three feet of roof eaves be covered by an ice and water barrier.

Roof Exhaust Vent: The outlet space left open at the highest part of the roof to provide proper ventilation and release of hot air. Roof vents can be the old-style box type, power vents, or a modern ridge vent system. The structure and style of your roof will determine which style of ventilation will work best.

Roof Inlet Vent – ​​The inlet space left open in the lowest part of the roof to provide adequate ventilation and the infusion of fresh outside air. Inlet vents can be gable vents or soffit vents. The structure and style of your roof will determine which style of ventilation will work best.

It is important to do your homework before discussing your project with a roofer or roofing company. There are a large number of options for shingles, underlayments, vents, and decks, and a wide variation in the cost of each type of material. Each component of a roof is critical as each piece must work together as a system once properly installed. The failure of one component could result in the failure of the entire system.

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