Hello, I am not a roofer. I need a new roof on a house with hips, and one ridge of 47 ft. I have been told that the ridge is not long enough for a ridge vent to be adequate. I have two quotes. One suggesting 3 attic power vents of 1170 can each. The other suggests the ridge vent and hip ridge vents. I have 299 ft of hip ridges. My atti square feet is 3525. Which option would you choose. I have more than adequate soffit intake vents. Thanks for any feedback. Brad
Post an aerial view…
Don’t seem to be able to copy aerial into chat response area. I will keep trying.
Garage ceiling finished?
Yes, their is drywall in the garage ceiling.
Ridge vent on longer ridges, rvos on hip sections. Do not use hip vents, they make no sense.
Thanks for reply. Might I ask what rvos means?
I’m currently working on a big, steep, cut up, hip roof.
I am removing the passive vent scheme and installing a power vent.
Sorry that is just a vent we use here. It is just a standard mushroom vent over a 7”x7” opening. Keep in mind venting issues change dramatically in different regions.
tuck in power vent on main and garage pyramides and regular tiny vents on smaller triangles ,ridge vent isnt enough imo
It’s obvious that you understand and aren’t educated by a salesman!
Thank you all for your comments. I really appreciate everyone taking the time to give me opinions. Never knew roofing was so involved, and not cut and dry about what sort of intake and exhaust vents needed and types to be used. Also, never thought once about the fact that our house had hip roof with very little ridge when we bought it. Thanks again, Brad.
My understanding is you need 1 sq.ft of net free ventilation per 150 sqft of attic space, that number increases to 1sqft per 300 sq ft of net free insulation if you have a vapor retarder on interior side of attic insulation. I didn’t do the the math but I think you are good
Thank you. That is sort of my understanding as well. I just got a revised quote from my roofer saying I need 41 exhaust vents on my roof. My attic has 3525 sq ft. Who has 41 box vents on their roof. What is wrong here. My dilemma is that with 3525 sq ft I calculate I need about 33 box vents (3525/150=23.5 sq ft nfa needed divided by 2 for 1/2 intake 1/2 exhaust =11.75 sq ft times 144 sq in per sq ft= 1692 sq in of exhaust vent. Avg box vent 50 in nfa = 34 box vents (1692/50) close to his 41. But who has 34-41 box vents on their hose. No house I’ve ever seen comes anywhere near that many on their roof. Can someone explain? Thanks again for responding.