[quote=“geapea”]On the attic question…It has cathedral ceilings in the entire upstairs. After the roof, I’ll be fixing the inside to provide ventilation flow up to the ridge.
On the midroof SmartVent…This winter the snow built up on the overhangs didnt melt for sometimes a week or more. The heat caused the main roof to melt much faster. At times you could see visibly thick snow on the overhang and much less to none on the main roof. I dont know if it ever would get bad enough to back up into the vent, but at the very least it would seem to be ‘blocked’ until all the snow melted. Since all the roof intake would be done this way, my concern would be that venting stops for some days/weeks during the winter. Of course, maybe this isnt enough ‘time’ to be a concern?
(pitch is ~7/12)
Thanks for your responses.[/quote]
One of the main and essential functions of proper fresh air intake ventilation balanced with an equal NFVA of continuous ridge line exhaust ventilation, is to create what is known as a Cold Attic Assembly.
You might want to consider each individual rafter bay in the vaulted/cathedral ceiling areas to each be a seperate containment of attic space.
Upon exhausting the hot arir contents from the interior rafter bays or attic space, and even more efficiently with the addition of the Smart Vent being installed just at the heated wall juncion, on the warm, interior side, the air flowage wil reduce the interior heated environment to a similar temperature as the exterior climatic conditions.
The current super-heated interior environment is the cause of the upper roofs snow meltage and the overhange are akin to bridges, whereby the sign posted state that “Bridges Freeze Before Roads”. The same affect occurs on the unheated soffit overhangs, which have no underlying heated environment to melt the snow and ice.
Continuous fresh air intake ventilation, using the Smart Vent by DCI Products and continuous attic and rafter bay hot air exhaust, using the Shingle Vent II by Air Vent Corp., has been my premier solution to similar situations.
I even provided this exact same solution on a manufactured home in an elderly retirement center this past November, which withstood the entire duration of this extreme winter ice damming season without any negative consequences at all.