Venting an Attic (Hip Roof) with a Custom Chase – GreenBuildingAdvisor

Hi, I’m looking to get opinions on venting an attic by using a custom made chase. Climate Zone 6.

It’s a 100 years old house with a hip roof and hip dormer (Foursquare house) It has board sheathing.

There are soffit intake vents but no ridge vents. We could see condensation on the underside of the asphalt shingles. There was no membrane under the shingles which is currently causing leaks.

The attic floor is insulated with old fiberglass batts with those pink plastic rafter vents.

There is no air-sealing around the attic door.

There is a lot that could be done for energy efficiency, but we were only asked to put an estimate together for a new standing seam roof.

There is no plan to use the attic space so it will remain as is.

Because of the roof shape, we are limited to adding a short ridge vent at the dormer.

There is an old unused brick chimney in the center of the main ridge. We are planning to knock it down to the floor level. This would allow us to frame an opening for an exterior chase for ventilation.

The main ridge is only a few feet so a chase would allow for more ventilation.

We can run the panels up the sides of the exterior chase and make it look pretty.

We’ve done it before for a chimney but never for ventilation.

Are there downsides to our vent chase plan? What would you recommend for venting a Foursquare house’s attic ?

They might choose another company to do screw-down roofing instead of standing seam so we are limited with trying to keep our estimate low with a simple elegant solution.

– Jeanne