Greetings, An engineer in town just called me with an interesting question. "Do you have any written documentation to show that gable end vents and continuous ridge vents should not be used on the same roof?" I had to admit that I had never herd anything about this but that the idea of the gable vents some how "short circuiting" the upward flow (convection) from the soffits to the ridge was interesting. The idea is that the gable vents would feed the ridge vents and there would be little or no air movement through the main area if the attic. This seems very unlikely to me in the real world but hay, I have been wrong before and surly will be again in the future... Are there any roofing experts out there with documentation about this? Many thanks, George