Proper Balanced Ventilation?
When re-roofing this weekend I pulled out the old power vent and installed cobra rigid vent 3. I want to make sure I install soffit vents in a way that will provide proper balance to the ventilation system.
There is 44' of open ridge vent (actually cut out from the roof, it's not cut all the way to the edge, despite being installed end-to-end). This yields 5.5SF of free ventilation at the ridge, so I am aiming to have at least that much at the soffits, ignoring the 4SF or so that are provided by the gable vents.
My existing soffit vents are woefully inadequate, only providing less than 2F of ventilated space. They will be replaced, and my question is as to how to do that.
About 1/4 of the home has cathedral ceilings, and they are insulated in a way that does not provide for ventilation (the bats pretty much fill the space, and the soffit vents are only between certain rafters, not all of them).
The ridge-line runs east-west, and the cathedral ceiling is on the Southeast quarter of the house. My plan was to provide evenly spaced soffit vents on the north eve, and large vents on the Southwest eve, roughly balancing the ventilation between north and south, even thought the south would be poorly ventilated on the eastern side.
Is this a good plan?
In the meantime I have removed one 8'x10" piece of Soffit from the north side of the home, in the center of the span to provide for temporary ventilation. Is this OK for a couple of weeks?
Last question: the 24-year old three tab feltless roof did not show any signs of blistering, etc with the old power vent arrangement, will my GAF timberline roof with 15# felt be more or less susceptible to heat damage? (Color is about the same, maybe a shade lighter)
Thanks to everyone here who provided advice going into this project. I learned a lot and had confidence guiding the installers through the process.