Proper ventilation ensures a cooler attic in warm climates and a dryer attic in cold, wet climates. It is important in preventing structural problems to the roof, maintaining a consistent inside temperature, and saving energy costs.
A general rule for free ventilation area is 1/300 of the horizontal area, or slightly less than H square inch of vent area for each square foot of attic floor. This should be properly balanced between equal net free area in the high vent and the low vent.
The most effective ventilation is a system of soffit and ridge vents. This brings ventilated air across the underside of the roof sheathing where it reduces radiation of heat to the attic floor in warm seasons or climates, and prevents condensation in cool situations. This system also creates a positive airflow in the attic space, which is achieved through wind pressure and natural thermal effect.
Additionally, a metal roof will help reflect heat away from the roof. The reflective properties of metal roofing have been shown to decrease cooling costs in warmer climates such as Florida by as much as 34 percent. Another benefit of metal roofing is the air space some products allow between panel and roof deck. This added ventilation further reduces the chance of buildup of condensation or heat, based on climate variations.
In re-roofing situations, this air space also protects the new metal roof from being damaged by curling and deteriorating shingles of the old roof.
TIP submitted by ATAS International. For more details, visit www.atas.com or call 800-468-1441.
I am looking to buy a metal building for my new shop' I would appreciate any information you could send me.
By Ronnie Cothren