 Adequate roof ventilation for your home is a vitally important issue If you study the background of house building trends in North America or in the United states, you are likely to observe that in most cases, roofs in the earlier days functioned not only by protecting the inmates from the elements but also worked as natural ventilators. As a matter of fact, the roofing materials and their mode of application allowed free movement of air that resulted in adequate ventilation of the attic spaces. So, additional ventilators were not needed at all. However, when bituminous roofing materials and subsequent composition shingles became popular in the United States, the roofs became almost hermetically sealed, obstructing all forms of air flow through them. Though this new roofing mode proved excellent in minimizing ice and precipitation problem, it created a different kind of dilemma. The ventilation being sealed off, moisture stared building up under the roof which in turn caused deterioration of the plywood structures. Furthermore, water vapor started condensing on most metal structures, causing them to rust. What is more, during the winter months, elevated inside humidity content, together with low outside temperature caused frost to form on the roof deck bottom as a result of which it started losing strength, eventually causing the roof to crash! Not that the summer days were any better. The heat that used to build up in the attic area in summer during the earlier days tended to cool off at night because of the natural ventilation provided therein. But in the present case, when the attic is not ventilated or poorly ventilated, heat builds up within a few days that raise the temperature in the attic. If we go by Air vent Inc’s Principles of Attic Ventilation, we will be shocked to find that a day temperature of 90° C without attic ventilation is likely to heat the roof sheath to 170° C or more. However, attic ventilation can be achieved by several methods that include the use of Gravity Ventilators, Wind assisted Ventilators and remote control Power Ventilators. Irrespective of the method used, all of them can provide uniform ventilation of the attic area as a result of which temperature and moisture can be controlled. Nevertheless, the most common and energy efficient method in which attic temperature and moisture control both are accomplished to a reasonable extent is through natural ventilation process. To be precise, it involves two basic principles, namely, (1) When air gets heated it loses density and tends to rise and (2) flow of wind around a home or a structure gives rise to relatively high and low pressure zones. Also, when a space consists of high air outlets along with low air inlets, natural ventilation occurs. But remember, the greater the vertical distance between the outlet and inlet, higher will be the volume of ventilation. This is one of the reasons that roof outlets are installed at or near the ridge while inlets are found under the roof overhang or close to the ceiling line. So far as vent types are concerned, slotted or perforated inlet vents may be installed as solo units or in a running form (several units) like a continuous strip. However, with this type of wind ventilation one is often confronted with a typical problem that concerns change in wind direction. This naturally upsets the high and low pressure areas around the site. One of the solutions to this problem includes the installation of the outlet vent near the ridge and the inlet vent in the soffit area. Since a Hip Roof has soffit area all round the house, this works best with this type of roof. If you find the issue too complicated for you to handle, please get in touch with Mr. Fred L. Bolanz, founder of the renowned CANYON CREEK ROOFING COMPANY of Texas who not only has the necessary home ventilating implements but also possess the know-how for proper installation of the vents, etc. In fact, you are likely to come across some of the pics illustrating roof ventilators on the website.
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