When it comes time for a roof replacement in Rochester NY, roofing ventilation may not always be a the forefront of your priority list; with more emphasis on details like shingle color choice, drip edge metal, roof decking and roof flashings- adequate roofing ventilation is all too often overlooked. What good is a new lifetime roofing system if the shingles and roof decking fail prematurely from a lack of a properly balanced attic ventilation system. Most ice dams and winter roof leaks can also be associated with improper roofing ventilation and attic insulation, not improper roofing installations. When we discuss roofing ventilation with our clients there are 5 frequently asked questions that seem to be common inquiries.
1- Why do I need attic and roof ventilation? A properly balanced roofing ventilation system will reduce heat build up in your attic and roof decking in the summer, moisture during the winter and help prevent ice damming during heavy Rochester NY snow storms. All of these processes help prolong the life of your new roof, roof decking and rafters; as well as increasing the comfort levels in your home and decreasing utility bills. While it may appear that the removal of summer time heat is the biggest advantage, it is actually the control of water vapor in the winter months that will prevent mold, rot and a decreased r value in attic insulation.
2- how much roofing ventilation do I need? The starting point for any proper roofing ventilation system is to measure the length and width of the attic floor and figure the square footage of the floor. The code minimum for adequate roofing ventilation is: 1 sq ft of net free area of venting for every 150 sq ft of floor space. In the opinion of Ron Ferris and Son Roofing this formula is acceptable unless you have a roof with a greater pitch that may cause the volume of attic air that needs to be ventilated.
3- what is the proper way to ventilate a roof? A properly flowing roof ventilation system should have an Intake and Exhaust. What this means is that an equal amount of net free area should be installed in the soffits/ overhangs at the roofs lowest bottom edge as an intake and again at the roofs peak with roofing vents. This allows dry, cool air to enter the attic space at its lowest point and push any warm, moist air out through the roof vents. A truly proper system will have a balance of 50% intake and 50% exhaust.
4- The more roof vents I install is better, right? While it is okay to exceed the recommended amounts of net free area of ventilation, it is never okay to use or mix more than one type of roof vent. This can cause a short circuit of sorts in your ventilation system. Airflow is meant to follow the path of least resistance from the bottom of the roof edge to the roof peak and out. When you combine different types of exhaust venting and place them at various heights on the roof line they will actually work against each other and exhaust vents can begin to function as intake vents pulling in hot air from the roof line and trapping warm, moist air in your home. Intake vents however are okay to combine various forms of venting.
5- How do I vent my house if it has different height peaks everywhere? While it is okay to vent multiple peaks that run parallel or at angles with each other, the rule for peaks of different heights is; any peaks or ridges more than 3 feet apart, than only the highest peak is to be vented. The reason for this is the same as installing multiple types of roof vents at different heights. The higher elevated vents will begin to pull air in through the lower vents instead of exhausting it. It is best to seperate attic spaces with plywood or plastic sheeting to create different distinct areas to be vented.
If you have any additional questions about incorporating proper roofing ventilation in your new roof in Monroe County or Wayne County, contact our owner today. He will personally meet with you and discuss a plan that will meet your individual needs and budget. Call us today @ 585-288-0895 and schedule your free roofing estimate!