Soffit venting – balance front to rear?
It’s the time of the year for attic venting questions…
How important is it to have eave vents on both the front and back of the house? I gather that it is not ideal, but how much of a circulation trade-off are you making if you have the correct NFV at the eaves, but it is all concentrated on one side of the attic?
I recently realized that my attic, in addition to being woefully undervented at the soffits in total, also has no vents on the front soffits. A quick inspection of my neighborhood revealed that none of the various builders installed soffit vents in front, presumably for improved cosmetics.
So, as I add soffit vents, can I get most of the ventilation benefits if all soffit vents are in the rear of the house, or do I really need to an equal NFV in the front?
Replies
You want them all around not for "balance" but rather to assure that all corners of the attic get vented.
View Image
sobriety is the root cause of dementia.
In my opinion, soffet vents only really work when they go completly around the house. A light breese on one side of the house creates a low pressure area on the other side which causes the vent to work. In general, soffet vents are well below the high heat/high humidity air which hangs in the very top of the peak of the roof, so to get the vents to exhause the bad air, they should be all the way around the house. If your prevailing winds are consistent from one direction, then you could possibly save some money and put them on the high pressure/low pressure sides, but the cost savings is probablyu not worth it. Once insulation gets damp, it almost immediately looses most of its insulation value and is hard to dry out, in the long run, continous sofet vents are a great deal.
Dennis
What you want in your roof venting system is flow-through ventilation. This means you need both 'input' and 'output' vents. Soffit vents are generally where fresh air enters the system; ridge vents, wind-powered turbines ('Charley Nobles') or gable-wall vents are most often the exit. Prevailing winds have a lot to do with when and where the air enters and exits...but winds do shift through the seasons, and that is why you need soffit vents all around and a good vent of some sort up high, too.
If the houses in your subdevelopment were all built with no soffit vents on the front, you should question whether or not the crappy builder who put them up even provided ventways in the rafter bays on the front side of the roof. If he did not--and you'll have to get in there to find out--you will be wasting time and money putting in vents or perforated soffit panels until you rectify that.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....