Even without soffit vents a ridge vent is much more effective than gable vents paulcp thinks hammer is right.
Gable roof ridge vent.
Gable vents will alter the air flow around the ridge vent and especially when wind is parallel to the ridge at right angles to the gable can actually reverse air flow through the ridge vent pulling rain or snow into the attic.
And the answer is you should block it off because it does interrupt that flow of air from the soffit under the sheathing and out the ridge.
Houses with gable roofs may also have vents located on the side of the house as high as possible within the peak of the gable.
You will also discover that this product can work by itself to release moisture from the house which is especially useful during the winter months.
Roof ridge vents do work well when there are soffit vents or box vents that help to draw air into the attic.
It will run the entire length of the gable roof peak.
Ridge vents are much easier to install because they sit on top of the roof at the peak.
So if you can have a soffit vent and a ridge vent that s the best situation.
Installation first requires a wood frame made of 2x4s installed from the attic between two studs.
That means you have a lower risk of mold or mildew development.
Gable mount attic fans quickly remove a larger volume of hot and or humid air from your attic compared to static ventilation which helps save money on your heating and cooling costs.
A few screws and some shingles will easily attach the ridge vents to the roof.
By having the gable vent you get some sort of turbulence up there that interrupts that flow.
You merely have to climb up to the roof and place the ridge vent.
Gable vents are a type of louvered vent that can act as an intake or exhaust vent depending on which way the wind is blowing.
Whether round triangular or rectangular these gable vents can be.
I added a attic fan 1500cfm onto the gable but i have the airflow coming in from the outside instead of pushing air out.
The first step is to check out this 60 second video and learn about the 300 1 rule the difference between intake and exhaust ventilation and why proper ventilation is so important to get right to help calculate your attic ventilation needs visit gaf ventilation calculator.
The whole point to a ridge vent is that it takes air from all along the bottom of the roof line and exits it out the top kind of like a toilet.
I have ranch house that has ridge vent soffit vents and two gables.
The problem with gables is they short circuit the air flow paulcp writes.