I plan to install 6″ Broan 842BL wall vents (2) on the end wall of my colonial house. The desired location is in the narrow strip of siding between the main roof and the adjacent garage roof. See pics. This 30 plus year old house never had the bath fans vented anywhere, ceiling fan was just open to attic, so I am finally going to fix it. I don’t want use roof vents, nor do I want to vent at soffit. My choices of wall vent locations are limited (avoid long duct runs, keeping ducting in rear of attic in case I ever want to use that space, and aesthetics from street/driveway. My desired wall cap location is shown on pics as well as a pic of the worst snow we had in 30 years, and also a sketch showing that I can get about 9″ of clearance between bottom of wall cap and top of garage roof.
Any experience on risk of snow blockage / water intrusion issues for this wall vent configuration would be appreciated, along with any recommendations you may have.
Thank you,
Dan
Replies
You could save some space by using 4" vent and ducting with a booster fan.
You don't say where you are, what the climate is like, and how much snow you actually get. That might help.
Some considerations based on my experience as a homeowner that's been dealing with my roof and attic a lot: The vent probably won't get blocked, at least not for long. Any air or warmth leakage from inside will melt the snow. What you might get is an ice-dam at the bottom of that edge where the thin strip of siding meets the edge of the garage roof. Unless that wall is really well insulated, the snow right along it probably melts away in the winter anyway but having the vent there should melt a nice bare patch and that all drains down to the edge. The dam may not do any harm, that area should be well flashed.
That area is also a bit more complicated because of the flashing. If the flashing and/or siding need to be redone down the road, that vent is going to be something else to deal with. That's probably not a real concern and overthinking it.
Thanks for feedback,
l am in Massachusetts near Boston.
I am going with 6" due to ducting runs and fans which I have already bought. My roof is about 6 years old and in good shape. They put an Ice and Water Shield down at bottoms. Although I have a history of ice dams (see pics); since new roof, we have not had water intrusion. I plan to increase soffit ventilation to get attic ventilation up to code and will be adding attic insulation in main part of house (walk up attic). The roof over the garage (and master bedroom) is a cathedral ceiling, so I will not be adding additional insulation in the area of the garage roof near the wall caps.
thanks
Dan