Commonly, a house has gable-end vents, not soffit vents. What's one to do when reroofing? Half the battle may be to convince a homeowner that ridge vents combined with gable-end vents don't work. A GAF bulletin cited spells this out, and may be helpful in making your case for either blocking the gable-end vents and installing ridge and soffit vents (at considerable increase in budget to retrofit the soffit vents) or leave gable-end vents as they are.