Roofing 101
What is Composite Roofing?
Composite Roofing is a light weight alternative to the traditional products (Asphalt Shingles, Wood Shakes, Natural Slate and cement or clay tile) on the market. Composites or Synthetics can be made of either a base of rubber or plastic along with fillers or other additives. Composite roofing is made to look like the natural products in mainly three categories; Wood Shakes, Slate and Barrel Tile.
Four Reasons to Ventilation a Roof
1. Removing moisture from roof cavities
2. Controlling ice damming
3. Enhancing roofing material life span
4. Increased occupant comfort
A ventilated roof system can only work properly if:
• The building envelope is tight enough to prevent warm, moist air from escaping from the building interior into the roof assembly.
• The roof assembly has enough insulation and it is properly installed.
• There is enough exhaust ventilation space to match the amount of intake ventilation.
• Intake and exhaust areas must also be evenly distributed to provide uniform cooling.
• The outside air is able to absorb moisture equal to or faster than is it accumulated.
New Products on the market that solve ventilation challenges
• Intake - Vents that are used for on the roof intake, a substitute for soffit ventilation.
• Exhaust - Vents that are used for exhaust just off the peak of the roof for application where there is a large center beam or a shared fire wall.
• Shed (Clerestory) - vents used to ventilate where roof meets a wall - porch or shed roofs
• Hips - ventilation products designed to ventilate on the hip of the roof.
• Tile or Metal Roofs - Ventilation products used for Tile or metal roofing materials.
Some benefits to look for when selecting a ventilation product
• Easy to install
• Certified performance - Building code certification for this category include ICC (International Code Council), Miami Dade, TDI (Texas Department of Insurance) and UL (Underwriters laboratories).
• Attractive appearance - offering curb appeal
• Energy Efficiency - When an attic has proper ventilation the life of the roof will be extended. The roof will also be protected from elements that can damage the roof structure and reduce the life of the roof eliminating energy waste.
Glossary of Roofing Terms
Roofing Square: 100 Square feet.
Pitch: Rise of roof per 12 feet.
Rake Roof: The inclined edge of a sloped roof over a wall.
Gable: The upper portion of a sidewall that comes to a triangular point at the ridge of a sloping roof.
Hip: A type of roofing containing sloping planes of the same pitch on each of four sides. Contains no gables.
Ridge: The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.
Soffit: The finished underside of the eaves.
Eave: The horizontal, lower edge of a sloped roof
Hip and Ridge Cap: Composite cap that covers this part of the roof.
Rake Cap: Composite caps that cover the rake of a roof.
Slope: The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.
Take-off: A plan for a roof that estimates the materials needed and the costs associated with the materials. Typically a finished roof take off will determine how many roofing square are required for the job.
Stack Effect: Attic air heated by contact with a hot roof on a warm day tends to rise. This is natural convection, which pulls cooler air from the soffit up towards the ridge. Natural convection, with a balanced system of soffit and vents at or near the ridge is the most effective means of venting the roof.
N.F.A. (Net Free Area): The net free area for any airflow pathway (airway) shall be the gross cross-sectional area less the area of any physical obstructions at the smallest or most critical cross sectional area in the airway. The net free area shall be determined for each airway in the installed device.
Although related, airflow and net free area (NFA) are separate measures of attic ventilation performance. NFA is a static measurement; airflow is a dynamic measurement. NFA is a mathematical calculation independent of field conditions. This value remains constant.
Airflow: is a performance measure that varies based on the conditions to which the vent is exposed. Variable pressure differences across a roof (such as that produced by wind or stack effect) will induce different flow rates.
CFM (Cubic Feet per Minute): indicates a mechanical device usually electric or solar powered that will draw air out of the attic at a constant and consistent rate.