I'm inspecting some aspects of my home's attic. It's a half-story finished space that has a closet where a drywall panel was left loose, supposedly to provide either temporary or permanent access to the unfinished space. After opening the panel, I was surprised to see rafter vents installed all the way from the soffit (an expected location) to where the half-story wall top plate is. I've only done one attic insulation project, and I used a single rafter vent along the perimeter of the roof to ensure that insulation didn't prevent air flow from soffit to ridge. I know this job was done by the previous homeowner, and my gut tells me that using a rafter vent this way basically doesn't do anything. Is that assessment correct or is there something I'm missing about how these perform?

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1 Answer 1


You're probably right that the segment between the insulated areas doesn't do much, especially considering that it's not sealed well at all (which is normal). The upper and lower areas obviously help keep the gap open. However...

  • Full venting like that could very well improve convection (the chimney effect), resulting in a cooler roof deck and therefore a cooler attic during the hot season.

  • It could also improve attic insulation efficiency by reducing drafts across it. Fiberglass is hardly windproof, so a drafty attic is going to scavenge more heat than a calm one during the cold season.

  • It's not really a problem. There shouldn't be a source for moisture in your attic, so drying isn't needed, and if there was a bit of moisture the leaky nature of those vents would allow its dissipation anyway.

I wouldn't mess with it, were this my attic. I'd just look for areas where the insulation itself isn't well placed or thick enough, or where it's not in direct contact with the surface behind it.


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