Ventilation For Your Roof
Issues under the roof shingles
Your attic is hot all summer long. The reason is the sun shining on your asphalt roof shingles. They are usually dark in color, and the asphalt is just like the road in front of your house. Too hot to touch.
The surprising thing is that high heat will damage your shingle roof, and shorten its life.
The solution is to ventilate the attic to allow excess heat to exit the house. This protects your roof, and in the process, makes the upstairs rooms cooler in summer.
Building code requires the attic to be ventilated, as do the shingle manufacturers. In fact, if your attic isn’t properly ventilated, your manufacturers guarantee is generally void. Not a good thing when you put an expensive roof on your house.
A salesman showing you a warranty card from the manufacturer is trying to get a sale, but if the details of a proper installation aren’t followed you might find out that the warranty won’t be honored by the manufacturer.
Here are some approved methods to properly ventilate your attic.
Air needs to come into the attic at the bottom edges. This is usually done through vents in the soffits. There are alternatives like vented drip edge and intake vents low on the roof. Convection takes the hot air up and out through ridge vents or an automatic exhaust fan.
Older houses don’t have ridge vents of vented soffits. If you have no ventilation, you won’t be “grandfathered in” when it comes to warranties.
Another issue that we commonly see is soffit vents being applied over solid soffits. We see this frequently on ”flip” houses where the remodeler tries to make everything look fresh on the outside. If the old wood was not cut away, these vents will be useless.
Another pitfall is insulation being installed over the intake vents. There are baffles made to keep the air flow going around the insulation. Without them, you have no
I’ve seen fairly new roofs with isolated patches of buckling shingles because the vents were inadvertently blocked in a single room of the attic.
If you have louvers in both ends of your attic, they will only work when the wind is blowing from the right direction. To make the ventilation system function correctly, they need to be blocked off and a soffit style system installed. Never have more than one system on your roof. They generally cancel one another out. The classic example is having an exhaust fan two feet away from the ridge vent. Your electricity simply powers a fan sucking outside air through the ridge vent and blowing it out of the house. It does nothing to cool your attic.
If you stick your head into your attic area with the light off, you should see light coming in at the bottom of the roof slope. That tells you that your soffit vents are open. Good roofers will always inspect the attic to understand the ventilation issues in your particular house.
Good ventilation is easy to achieve on most houses, but it takes a thoughtful approach in some older structures.
A roofer certified by the manufacturer is a good place to start
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