Roofing
A roof is essential to any building that protects the structure and its occupants from rain, snow, sunlight, and extreme temperatures. It can take various forms, including flat, pitched, or domed.
Roofing is challenging work that requires specialized training. Roofers need to follow safety guidelines to prevent injuries and accidents.
Plywood is popular for roof structures due to its strength and stability. This engineered wood is a composite material consisting of multiple thin layers of veneers, or “plies,” glued together with adhesives. The grain in each layer runs in alternating directions, which provides the material with exceptional strength and resistance to twisting and warping.
Unlike solid lumber, plywood is less prone to cracking when exposed to moisture, making it ideal for roofing materials. It’s also lightweight and cost-effective, making it an excellent choice for a wide variety of construction applications. In addition to its durability, plywood is easy to work with and can be stained or painted to suit a project’s aesthetic.
There are several types of plywood available on the market, each designed for specific uses. Choosing the correct type of plywood is essential for ensuring that your roof will be strong and durable. For example, structural plywood sheets are made to meet certain standards for strength and durability, while other varieties may be better suited for decorative or general use.
The thickness of plywood used for a roof can vary depending on the load that will be placed on it and the distance between the rafters. For shingle roofs, a thickness of 3/8″ is commonly recommended.
When selecting a thickness, be sure to consider the weather conditions in your area. Heavy snow loads, for example, may require a thicker thickness.
There are also different grades of plywood, ranging from A to C. Grade A is the best quality, with a flawless surface perfect for interior work and areas that will be covered. Grade C is an economical choice that offers good strength, but has visible defects like knots and patches on the face.
Besides the thickness of plywood, another important factor is the type of adhesive used to bond the wood veneers together. The type of adhesive chosen depends on the plywood’s intended usage. For example, a phenol-formaldehyde resin is often used for sheathing exteriors because it’s resistant to moisture. Other types of adhesives are suitable for other applications, such as glues made with urea-formaldehyde or methylene-chloride.
Shingles
Roofing shingles are what give your roof its visual appearance and protection. They are usually manufactured from wood or a fiberglass composition but are also available in a variety of other materials. As part of a roof system, shingles are laid in courses, with each shingle slightly offset from its neighbors. They are held in place by nailing, either to the underlayment or directly into the roof rafters.
The most basic shingle is the 3-tab, which has a single layer with cut-outs forming three different tabs. It’s less expensive and a good choice for most residential roofs. Architectural shingles are thicker, with two layers of shingle material bonded together for added durability and beauty. These shingles are the most common in home construction today.
There are several types of wood shingles, including Alaskan yellow cedar and Eastern White cedar. Both are durable, attractive and easy to work with. But they require regular staining or painting to prevent them from bleaching to a grayish color and losing their protective oils. During a rain storm, more water is channeled along eaves and complex rooflines, which can cause these areas to wear faster than other parts of the roof.
A ridge is an area at the peak of the roof that sheds water down both sides of the slope. A shingle called a ridge cap or ridge slate is used to cover the ridge and protect it from rain, snow and other elements. These shingles aren’t as easy to install as field shingles and must be custom-cut to fit your roof. To help with installation, a ridge vent is sometimes installed. Flashing is typically installed around plumbing stacks, attic vents and other roof penetrations, as well as around skylights, dormers, chimneys and other features. Ice and water membranes also are often installed at this time. They function by sealing the shanks of the shingle fasteners, adding an extra degree of protection to these tricky roof areas. This is also the time to complete any open valleys, which should be lined with a pre-formed width of corrosion-resistant metal.
Underlayment
When it comes to roofing, underlayment serves as the first line of defense against moisture infiltration. Without it, even the most meticulously installed roof can succumb to leaks, leading to costly repairs and structural damage.
Typically, a layer of asphalt-saturated felt or non-bitumen synthetic underlayment is laid on the roof deck before the installation of the roofing materials. During a rain event, the underlayment helps keep water from infiltrating the home by shedding water and dispersing it through the sheathing or draining systems.
This underlayment is traditionally made of varying blends of natural plant fibers and polyester. It has a flexible base layer that is drenched with asphalt for water resistance and is often fastened using staples. While it is water-resistant, this underlayment is not waterproof. It is most suitable for sloped roofs as it allows water to easily drain.
As a more modern alternative, synthetic underlayment is becoming increasingly popular due to its many benefits. Not only does it offer a higher level of protection, but it is also easy to install and is mold- and water-resistant. Additionally, these products are more durable than felt, and they resist high winds and extreme weather conditions.
Another benefit of synthetic underlayment is that it is fire-resistant, allowing the homeowner to enjoy peace of mind knowing that their roof is safe from the risk of fire. However, it is important to note that if pine or fir boards are used as sheathing, then a class A fire-rated underlayment must be used to ensure the integrity of the wood and protect the structure of the house.
Felt underlayment has several disadvantages, including its fragility and difficulty to install. It can tear during the roofing process, or it may become damaged by high winds. Its slippery surface also makes it dangerous for roofers to walk on during the installation process.
Rubberized adhesive underlayment offers more protection than felt, and it can be a great choice for colder climates, but it is prone to deterioration when exposed to excessive heat. In addition, it is the most expensive underlayment available, making it unsuitable for budget-minded projects.
Flashing
Flashing is a metal used to seal the gaps and cracks where roof materials meet other structures, such as walls and chimneys. It protects these vulnerable points from water penetration, which can cause serious damage to a home or business. There are many different types of flashing, each designed to fill a specific role. They include: step flashing, which seals the joint where a sloped roof meets a vertical surface like a wall; valley flashing, which seals the area where two roof slopes meet in a V-shape; drip edge flashing, which helps to keep water away from the edges of the roof and the fascia board; and counter flashing, which covers the base flashing and adds a layer of protection.
Roof flashing is usually made of a highly durable, weather-resistant metal, such as copper roofs or galvanized steel roofing. It can be rolled out and installed, or cut to size from coils or flat sheets of metal. The flashing should be matched to the colour of the cladding sheet in order to avoid any discolouration or corrosion over time.
There are also various types of flashing accessories, such as box gutter flashing, which is used to cover the ends of a shingle course, and fascia flashing, which adds a decorative finish to the edge of the roof. There is also pipe flashing, which consists of a single piece that fits around the circumference of a pipe. There is even ridge cap flashing, which is used to prevent water from seeping under the shingles at the peak of the roof.
Roof flashing is a vital part of any roof and should be carefully installed by an experienced professional in order to protect the integrity of a building. Regular maintenance and inspections should be carried out to ensure that it is still in good condition and working properly. In addition, keeping the surrounding area free of debris and ensuring that there are no cracks or holes will help to prevent problems with the flashing. For this reason, it is always a good idea to hire a professional to carry out any flashing work, especially when it involves the more difficult areas of the roof.