Roofing Ventilation 101
Here's how to calculate and plan roofing ventilation and the reasons why it is so important to do so.
07/03/2020
How do you calculate and plan roofing ventilation and why is this necessary? Well, there are actually quite a lot of benefits when your roof has sufficient ventilation. Number one, proper ventilation will increase the lifespan of a roof.
One good example of this is a condition called ice damming where ice builds up on your roof. This can create significant damage on your roof. Ice damming is a result of heat in your attic combined with the sun’s heat causing snow to melt on your roof. When the melted water gets to the edge of the roof there’s a possibility it will refreeze. This can compromise not just your roofing system but it will also destroy the integrity of your attic. With proper ventilation, hot air will be effectively removed from your attic so that it doesn’t melt the snow on your roof.
Another benefit of good roofing ventilation is that it helps lower energy costs. When outside temperature rises, people go indoors to keep themselves cool. When your roof is properly vented it will allow heat to dissipate, which means your AC’s workload will be reduced resulting to a lower power bill.
How do you calculate roof ventilation?
Step 1 – You’ll need a tape measure for this in order to calculate the dimension of your attic. If your attic spans the entire area of your house then it would be easier for you to measure the outside of your house. Let’s assume that your attic floor has an area of 1200 sq ft (30x40 ft).
Step 2 – In order to find the appropriate venting needs of your attic you’ll need to divide 1200 (floor area) by 150. The answer will give you your roof’s venting needs.
Step 3 – Your next step is to measure your roof ridge’s length. Multiply the length by 18 square inches. The answer is the amount of venting for a ridge provider per liner foot.
Step 4 – your next step is to calculate the dimensions of the soffit vents and then measure their areas. Make sure you have sufficient numbers in order to have extra venting for your attic. You can usually find the square footage of a soffit vent on the label. For example, if you use a 6x12 rectangular vent then it means you’ll need 10 of those since each one has around ½ square foot and you have to match it with the ridge vents.
Whether you are building a home or a building or you’re planning to do a major renovation, it is highly recommended that you carefully plan your roofing ventilation to ensure that your roofing system will function optimally and will serve you for a long period of time. We suggest you hire professional roofing contractors to do it since this is part of their job. They have an in-depth knowledge and understanding of roof ventilation calculations. To help you find the best roofing contractors in your area we suggest you look for them online and read reviews and testimonials about their previous projects.