Will combining roof venting systems cause short cycling?

by Abe Voelker   Last Updated April 19, 2018 09:21 AM

I'm looking into buying a new house here in Wisconsin that has soffit vents, ridge vents and some additional static roof vents installed. However, when the home inspector came through he said that combining ridge vents and roof/static vents is a problem because it can cause the air to short cycle and the attic won't vent properly, leaving moisture trapped. He said ideally you should have one intake system (the soffit vents) and one outtake system (the ridge vents).

The builder told me that the reason the static/roof vents were added was because the carpenter had made a mistake cutting holes for the trusses (or something like that, I'm not a handyman so didn't totally understand) and to fix it they just decided to add these roof/static vents over the holes, thinking that it would simply improve venting for the attic.

My question is, is the home inspector right and I should be asking for the roof/static vents to be removed/closed, or is it fine to leave them in?

Inspector's report (ignore stuff about baffles):

Inspector's report

Answers 2

Your inspector is correct. Air should enter at the soffit, and exit at either roof vents or a ridge vent. With the current setup air could be entering either the soffit vents or the roof vents, and exiting either the roof vents or the ridge vent. Since your soffits are covered with insulation (because there are no baffles), I'd guess that air is entering the roof vents and exiting the ridge vent. This means only the air near the top of the roof is cycling, which can lead to problems with the roof including a shortened roof life.

In my house there were originally roof vents in the roof above my garage. When they did a reroof they switched to a ridge vent, and as you can see they covered over the old roof vent openings.

Covered Roof Vent

On a side note: Inspectors are hired by you, and work for you. They have no reason to lie or mislead you, since they will not gain in any way from it. In fact, you can probably trust an inspector more than a random person on the internet. Seeing how you paid the inspector for advice, while I'm doing this for free.

March 27, 2013 14:07 PM

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April 19, 2018 08:39 AM

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