Every building structure requires a roof, whether it is a home or any other commercial building. The roof is what provides a shelter from the elements and protection for property and life. Roofs are supported on structural members that are anchored into the walls and any other framing structure.
Roofs can be flat or sloping and this choice will depend on the weather in the geographical area potential use of the roof (think commercial buildings). Roofs have different components and these must be correctly understood as a homeowner to know their functions and potential problems with each.
Basic components that make up a roof:
- Supporting roof structure
- Roof covering
- Fascia board
Supporting Roof Structure
The supporting roof structure that makes up the base for a roof can be in the form of walls, columns, and beams that are made from concrete, wood or steel. These have to be connected to a proper foundation that can withstand the imposed load as well as uplift pressures from the wind that can be imposed on a roof. The material used in the roof can vary and this can have a bearing on the total roof weight that comes on the support structure.
A truss or other configuration is required to anchor and accommodate all the other components on the roof that are required to complete the covering of the enclosed space. These trusses can be of wood, steel or even made up of concrete members that span the entire area to be covered. the shape and dimensions of this truss will depend on the slope of the roof and its pitch. Every truss must have proper arrangments that allow for the fixing of any of the supporting members that are required to take on the roof covering materials. These supporting members will be purlins and rafters to which the roof covering will be fixed.
Roof covering is made up of many different materials and the final choice can depend on aesthetics, cost, weather and other considerations. In most cases, roofs are covered with a base sheet made up of plywood or other material that covers the entire roof. On top of the plywood is the underlayment, felt or tarpaper, a layer of waterproofing material. Near the gutters, instead of using tar paper, ice and water guard is typically used which is much thicker and is coated with a glue-like substance that provides more protection than tar paper. It is used near the gutters because that is the location where all water flows and most snow will sit during winter months. Roof covering materials can be from a wide variety of asphalt shingles, metal panels, wood shake, country tiles, or other material when considering flat roofs and very mild pitches. The choice can depend on aesthetics and cost. The function of every roof covering is to provide a means to combat the weather and provide a roof that is leakproof. Most roof coverings require constant maintenance and the cost of such maintenance can often influence the choice of material.
The pitch of the roof is the difference between its highest and lowest points and provides the necessary slope that ensures that rain and snow flow away from the roof and discourages it from leaking. This pitch will also determine the configuration of the roof truss.
Roofs will have a ridge at its highest point, where the slopes from either side of a roof will meet. Because each slope is coming together, there will be a small opening between the two pieces of wood. A special covering called ridge vent and then ridge shingles will be used to cover and protect the ridge. This allows proper ventilation of the roofing system. In some homes, the roof is only sloped in one direction and may not require ridge protection.
Flashing is metal material that is used on any roof structure like a chimney or skylight that protrudes out of the roof. It is used to waterproof the junction between the roof and the structure. The metal is placed up against the structure, hammered to be flush, then caulked in place to provide maximum waterproof protection. Flashing is very vulnerable to the weather and requires special attention. This is often where leaks in a roof begin, because of the lack of care that was taken when flashing a roof.
The eaves are the lowest part of the roof and are required to be anchored to the roof truss. This acts as a support of the roof covering and ensures that it does not slide off the roof.
A fascia board is the wood material that is directly behind the gutters (if the home has gutters). This is used to support the gutters but also provide protection under the overhang. Often metal drip edge is used at the very bottom of the roof that sits in front of the fascia as a waterproof material. This protects the wood fascia and is bent outward so the surface tension of the water is broken and forced away from the home and into the gutter.
Gutters are a horizontal, metal, water collection system at the bottom of the roof. They are an integral part of the roofing system as they divert the water away from the home during a rainstorm. Gutters are sloped and can be interconnected to take water from one location to another if there isn’t a good place to outlet the water properly away from the foundation.
Downspouts are connected to the gutters vertically, taking the water collected downward, often to an outlet or they can be connected to the storm sewer system in urban environments. This prevents water from sitting in your front yard and other drainage problems when the water reaches the street and curb.
Each of these components makes up your roofing system and all have their own functions. Each part plays its role in protecting your home from the elements, giving you and your family a safe, dry place to live.