Roofing is the covering that protects a building or structure from rain, snow, sunlight, and wind. It also provides insulation and enhances the aesthetic appearance of a building.
Roof support can be made from a variety of materials. Some are fabricated from steel or concrete. Others are made from wood, such as plywood or Oriented Strand Board (OSB), or from different metals.
Plywood is a type of engineered wood that is used as the base for shingles, tiles or other roofing finish materials. It provides a sturdy foundation and helps to withstand the elements. There are different types of plywood used in different construction applications, and it is important to choose the right one for your roof. Choosing the wrong type can lead to moisture damage and rotting. The most common type of plywood is OSB, which stands for oriented strand board. This is made from wood strands that are interleaved with adhesives such as phenol-formaldehyde or urea-formaldehyde. It is then pressed and trimmed to its final size.
There are different grades of plywood, with A being the best quality. This grade has no knots and is typically reserved for structural purposes or areas that will be hidden from view. On the other end of the scale is grade D, which has many knots and blemishes. This is less expensive and is used for sheathing, or the outer layer of a building. There are also specialty types of plywood that are designed to meet specific requirements. For example, marine plywood is made to withstand exposure to the elements and is designed to resist swelling or warping. There is also structural sheathing plywood, which has been formulated to withstand stress and full weather exposure.
Unlike traditional lumber, which is solid wood, plywood has several layers of thin veneers, or plies, that are glued together to create a stronger and more stable product. Each ply is arranged at an angle to the next, which adds strength and stability. This is because wood has its strongest resistance when the force is applied perpendicular to the grain. This makes plywood much more durable than solid pine, which can sag and deform over time. It is also a more cost-effective choice than solid pine for sheathing and other structural applications.
Shingles
The shingles that cover the roof are a critical part of the overall roofing system. Affixed in a series of overlapping rows, they shed water and other elements away from the roof and toward the gutters. Shingles are available in a wide range of styles, colors, and materials. The shingle selection process involves more than just aesthetic preferences, however. Price, utility, longevity, and region-specific performance needs (such as algae protection) must also be considered.
The most common shingle material is asphalt, but shingles can also be made from wood, metal, clay tiles, and slate. The most durable shingles are those that are cut from mature, slow-growing trees such as red cedar or pine. These types of shingles are typically pre-treated with chemical preservatives and can last up to 40 years when properly cared for.
Whether they are constructed from wood, metal or a combination of materials, all shingles have some common components that make them effective at shedding rain and other debris. A high-strength fiberglass mat serves as the base for the shingle, and is then coated with a blend of mineral granules that help protect the roof from sun damage and other weather conditions. A strip of sealant is added to the shingle base for extra strength and protection against wind.
Once the shingles are in place, they are often covered with additional underlayment for overall secondary roof protection. This underlayment can be felt, tar paper or an asphalt plastic membrane. Special areas of the roof, such as valleys and where shingles meet walls, require flashing to prevent leaks.
When installing shingles, it is important to follow the manufacturer’s instructions for proper nail placement and positioning. Over time, improper shingle placement can lead to a variety of issues, including premature roof wear and tear. The best way to avoid these problems is to work with a professional contractor who is accredited by a shingle manufacturer. They will be familiar with the latest shingle installation procedures and can guide you through your shingle selection and installation options. In addition, they can recommend the best shingle materials for your home’s unique roof.
Underlayment
The right underlayment is essential to a roof’s long-term health. It helps prevent leaks, protects the sheathing and underlying structure of your home from moisture damage, and can even add insulation to your house’s energy efficiency. It can also help uphold warranties for roofing materials and improve overall roof performance.
Many different types of underlayment are available, with each type having its own advantages and disadvantages. The most important factor to consider is your climate, as some underlayments are better suited for certain weather conditions than others.
Felt underlayment is commonly used and is generally a good choice for homeowners on a budget. However, it can tear easily and must be protected from sunlight during installation. Typically, contractors will cover it with sheathing paper or other protective material to avoid water damage.
Another common underlayment is rubberized asphalt. This type of underlayment looks and feels like felt, but it has several key differences. It’s often more expensive than other types of underlayment, but it offers premium protection for your home. It can also last longer than other underlayments. Additionally, it is designed to self-seal around fasteners and nails, making it easier for installers to work on a roof.
Synthetic underlayment is another option that’s becoming increasingly popular among professional roofers. This type of underlayment is made from a waterproof synthetic base and coated with fiberglass to make it extra stable. It’s also much faster to install than felt or rubber and features a non-skid double-sided coating, which makes it safer for installers and homeowners. It’s also a great choice for high-wind areas as it can withstand winds of up to 110 miles per hour.
It’s important to remember that underlayment is not a substitute for sheathing paper or OSB. OSB or plywood that’s exposed to moisture can rot within a few months, leaving the rafters and other wooden beams of your roof vulnerable to structural damage. In addition, rotting sheathing can cause leaks, which will destroy the roof covering and cause major water damage to your home. If you notice water damage in your home, it’s possible that improper underlayment was used during the initial installation.
Flashing
Flashing is thin sheet metal used to seal the joints where a roof meets a wall or other vertical surface. It protects against water penetration that can lead to mold, rot, and structural damage. Typically, roof flashing is made from metal like galvanized steel or copper, but it can also be manufactured from plastic, rubber, and other materials. The type of flashing used for a particular roof depends on the weather conditions in a given region and the design of the building.
Roof flashing is especially critical for certain areas of a building, including low points where two slopes meet (known as valleys), roof protrusions such as chimneys, plumbing vents, and skylights, and the area where the roof meets an exterior wall. Without proper flashing, these areas are prone to leaks and other problems that can be very expensive to repair.
The most common flashing is base flashing, which is installed at the joint where a roof meets a wall or dormer. It protects against water intrusion and guards against shingle erosion at this vulnerable point. This flashing can be a single piece or several overlapping pieces that look somewhat like a staircase, and it may be covered by counter flashing.
Chimney flashing is another important type of roof flashing, which prevents water from seeping into a chimney. This flashing system usually consists of step and counter flashing, as well as a cricket or saddle that diverts water around the chimney base.
Other types of roof flashing include ridge cap flashing, which is installed at the peak of a roof to create a waterproof seal at this highest point. Pipe flashing is used to flash the gap around pipes that penetrate a roof, and it can be made from metal or a more flexible material like rubber or silicone for easier expansion and contraction.
Roof flashing can also be installed to protect walls at vulnerable points, such as windows and other points of structural support. This flashing can be embedded in a wall to help direct water that has penetrated the wall back outside, or it can be used to waterproof pipes, supports, cables, and other roof projections.