Properly venting a roof assembly where soffit venting is not possible – GreenBuildingAdvisor

I have a bit of a conundrum regarding venting of my (proposed) house build.

The house is a fairly straightforward rectangle, with a 6/12 gable roof. No hips, valleys or dormers. Located in BC, CZ 6.

Required venting design to BC Building Code would be for

    “a vent area of not less than 1/300 of the insulated ceiling,

    distributed uniformly on opposite sides of the building,

    with not less than 25% of the required openings at the top of the space, and

    not less than 25% of the required openings at the bottom of the space.”

Typically this would be achieved with 50-75% of the venting in the soffit to slightly pressurise the airspace, with the remaining 25%-50% in a ridge vent.

We have a very small property and thus will the building as near as allowable to the property line. Something I skipped over/overlooked was that due to proximity of our neighbours’ houses, we cannot vent the soffit space for fire separation.

During initial design, I just assumed I could add gable venting and it would not be an issue. I have since read that gable venting is not always an effective solution, and I am looking into alternatives.

One product I have stumbled across is SmartEave by DCI Products. Looking for any feedback available on this (or similar) product, particularly in areas that experience regular/heavy snowfall.

https://dciproducts.com/smartvent-eave-installation/

Part of the design process was pre-construction STEP code compliance and heat/loss gain calculations. These were both done assuming a cool/ventilated attic and blown in cellulose for the ceiling insulation. The roof truss design was also done with this system in mind. “Do a hot roof instead”, as one local contractor suggested, is not as simple as moving the insulation to the roof decking, it would require a lot of (expensive) design changes.

Dave