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Roofers – Be Ready for Changes to IRC and IBC Building Codes!

The only thing constant in this world is change and the same thing can be expected in terms of building design. One of the latest changes coming this year is the change with the International Residential Code (IRC) and International Building Code (IBC) ventilation codes. All roofer Houston contractors should be aware of and ready for these changes.

Although it frequently goes unnoticed, the ventilation system of a roof plays an important role in extending the life of a roof by keeping the temperature underneath the roof temperate to prevent damage to the materials that lay below. So how does a ventilation system work?

Ridge Vent Basics

One of the most important parts of a house’s ventilation system is the ridge vent. That is a semi- permeable material that is installed on the top-most end of the roof called the ridge. The material is installed on the entire length of the ridge for maximum coverage and then covered by shingles to make it unnoticeable.

The ridge vent is joined with soffit ventilation located underneath the roof deck. These two work together to keep a roof well ventilated. So how do these two works? It works on a very basic principle. Ventilation is maintained through the natural airflow. When air within the attic is heated, it rises naturally and leaves through the ridge vent. The escaping warm air would then create negative pressure inside the attic space causing cooler air to seep through the soffit vents. This cycle continues naturally keeping the temperature inside the attic within a normal range.

The idea of keeping a small opening on the topmost part of a roof may seem like a passage way for leaks during rainy season or snow, but that is not the case. Unlike traditional mushroom, pot or gable end vents, the ridge vent is designed with breathable barriers as well as outside and inside baffles that keep outside elements such as small debris, water and moisture outside. Latest ridge vent designs are also subjected to rigorous testing to simulate extreme weather conditions such as gale-force hurricane winds, heavy rain falling at 7 inches or more per hour, as well as heavy snow conditions before being given certification. As long as the roofer Houston installer follows the manufacturer’s product installation instruction properly, the ridge vent will ensure sufficient protection from the elements.

Importance of Ventilation

The roof is the building part that gets exposed to extreme temperatures. During summer when the temperature is at its highest, the heat will increase in the space between the rafters and eventually penetrate the house’s interior rooms. The high temperature will cause an increased demand for air-conditioning and drive up utility costs. Installing roof ventilation will effectively prevent heat build-up underneath the roof during the summer.

During winter, the same ventilation will also let moisture out that is caused by interior functions such as cooking and bathing. The ventilation will help protect the insulation from getting moisture-laden and preserve its insulating property by venting the moisture out. Another reason why it is necessary to get rid of moisture inside a home is because moisture actually grows mold and mildew which can leave stains on the ceiling and cause it to possibly collapse. Moisture will cause a roof to decay at a faster rate than would otherwise be normal.

Other than the accumulation of moisture, another common problem on houses without roof ventilation during the cold winter months is what’s known as ice damming. An ice dam develops when the temperature at the top end of the roof is warmer than the lower end of the roof. The uneven temperature causes the ice from the top of the roof to melt, collect on the low end of the roof and then re-freeze into ice that creates a blockage or dam. The accumulated water will eventually seep through the roof and soak the underlying structure. With ventilation installed underneath, roofing can keep the temperature equal throughout the entire roof preventing partial melting on the roof surface.

Identifying Ventilation System Needs

These days, the roof ventilation system is a standard design; however, there are times when the ventilation just doesn’t perform as it should. Verify the effectiveness of the ventilation by checking the attic for any of these signs.

  • Insulation that feels damp or moist to touch.
  • Uneven darkening and discoloration on woods making up the roof structure.
  • Darkening on the spots around nails.
  • Formation of resin beads colored orange on the wood.
  • Deformed and brittle roof shingles.

If these signs are present, the next step would be to determine the need for repairs or replacement of the roof structure before reinstalling proper ventilation. If the damage on the roof is minimal, then the problem can be solved by simply putting up additional vents so air can sufficiently move through the roof. The first action to determine the correct amount of ventilation is to measure the area of the attic in square feet then use that number to compute the NFA (net free area) that should be provided by the ventilation. The NFA refers to the amount of space available for air passage. In order for the ventilation to be effective, there should be balance between the net free area, the ridge vent and the soffit. As much as possible, the NFA of the soffit should as great as or larger than the ridge vent’s to allow maximum air flow.

The recent code language imposed both by the two agencies in 2010 that required an even amount between the ridge vent and the soffit for a higher efficiency in air movement was approved. The previous code set only a requirement for 80% installed attic ventilation on the top most end of the root. Homes that implemented this proposal had problems due to poor air circulation which led to increased moisture. This latest proposal will take effect this coming 2012. Prior to this proposal, the Roofing Assembly Ventilation Coalition had already successfully initiated a vapor barrier be placed on the part of the ceiling that is traditionally warmer during the winter; this was to be done in northern climates only.

Greater Ridge Vent Selections

When it comes to finding the right type of ridge vent for a building application, leading manufacturers have a broad selection of different types of ridge vent products that will ensure proper ventilation within an attic. Choices can be made from rolled and sectional ridge vents depending on the building’s ventilation requirements. Products for baffled ridge vents are also available for keeping dust and other foreign objects from infiltrating the attic. Most manufacturers offer a low-profile designed shingle so that the ridge vent is virtually unnoticeable when viewed from the ground. Choices can also be made from a variety of ridge vent designs that would match various pitches and roof styles and in different grades.

Effective roofing ventilation is one of the keys to building structures with longer-lasting roof lifespan and energy efficient building design. This is the message manufacturers continue to convey toward home builders, engineers, architects, officials dealing with building codes, and the public about the importance of proper application of roof ventilation.

Although change is inevitable, this change regarding the ventilation of attic space in a building is a positive one for attics where ridge vents have been installed. All roofer Houston contractors should take the time now to become educated on these changes and be ready when it occurs.