A Roof Has to Breathe at Both Ends

Air in low, air out high. Your house makes moisture all day from showers, laundry, and cooking, and it rises into the attic. Cool air gets pulled in through vented soffit at the eaves, picks up that heat and moisture on the way up, and leaves through a vent at the ridge. Block either end and the heat and the moisture stay in the attic.

It can have the wrong balance, which is the more common problem. More exhaust than intake doesn't help. If the soffits are blocked or solid, a ridge vent can't pull air from outside, so it pulls conditioned air out of your living space instead and drags household moisture up into the attic with it. Adding vents to an attic that can't take air in makes things worse, not better.

Trapped heat cooks shingles from underneath, which ages them years faster than the sun does from above. Trapped moisture condenses on the underside of the deck and rots the wood. Both happen out of sight, and both are why most manufacturer warranties are void if the ventilation is undersized for the roof.

Continuous vented soffit running the full length of the eave, a baffle in every rafter bay holding the air channel open where insulation would otherwise block it, and one continuous vent running the full ridge with a slot cut end to end underneath it. Intake at the bottom, exhaust at the top, and nothing in between blocking the path.

No. On a hip roof with a short ridge they are often the right answer, because there is not enough ridge length to run a continuous vent. Where the ridge is long enough, continuous beats intermittent, and one or two box vents doing the work of a full ridge line is undersized rather than wrong hardware. The question is how much exhaust the attic has, not which product it came from.

Usually yes, and it is standard practice. A ridge vent pulls the easiest air it can find, and open gable vents are easier than soffits. Left open, the ridge short-circuits through the gables and the lower two thirds of the attic gets almost no airflow. Blocking them is what forces the air to come up from the eaves, which is the whole point.

A continuous slot gets cut through the decking along the entire peak, and that opening is what actually lets the attic exhaust. A low-profile vent runs the full length of the ridge over it, nailed down and baffled to keep wind-driven rain and snow out. Matching cap shingles cover the vent, so from the ground you would never know it is there.

Not necessarily. A ridge vent only works if the roof is open underneath it, and the shortcut we find is a vent nailed down over decking that was never cut, or cut short of the ends. It looks finished from the street and vents almost nothing. That's one of the things we check in the attic, because from up there you can see daylight through the ridge if the slot is really there.

Yes. We measure what intake and exhaust the roof actually has against what the new system needs, before we price anything. Where the numbers do not work we add vented soffit, baffles, or ridge vent as part of the job, and those show up as line items on your estimate so you can see what you are paying for.