What are the options for an exhaust vent for cathedral ceilings that have a 4.5” wide ridge beam opposed to a stand 1.5” wide? My original plan was to use soffits, baffles and and a ridge vent but I am not sure a ridge vent is possible with such a wide ridge beam? Anyone have experience with this?
What is the final roof covering?
The roof covers a small 18x18 cabin
I meant roofing material. If metal, you can get oversized cap and split the ridge vent material. Shingles you can cut oversized cap from modified bitumen of a matching color. Simpler would be to frame the ceiling down 18" and install gable end vents. That would also allow room for ceiling fans, lighting, et al.
Sorry did not read your comment right the first time 
. We are looking at both metal and shingle but leaning towards shingles. Would you happen to have any pics of using the oversized cap from modified bitumen? Would you still use a normal plastic ridge vent or the roll material ridge vent or something else?
I was also thinking about framing the ceiling down. Would gable end vents be enough or would we want to add a box vent or two towards the ridge on the roof?
18’ is not much of a run. With eave vents, the gable end vents should be sufficient. I’ve seen a lot of ridge vent that wasn’t worth a damn and are overrated. But if you install box vents too high on the ridge they can leak in high winds due to eddy currents and may disrupt the flow of eave vents. All we’re working with here is convection. As far as cutting your own cap, get creative. To get 2" cut on either side of the ridge beam, plus the width of the vent itself, plus cap overhang on the vent, the total will be in the range of 10 to 12 inches on each side? DISCLAIMER…This is my opinion based on 40+ years of practical experience.
Thanks for the feedback! We plan to hire a roofer but so far haven’t found anyone that seems to have any knowledge on ventilation. When I ask about ventilation they just change the subject. We are in a rural area so it’s hard finding people. I found a few contractors on GAF and Certainteed website that are semi close so I am going to try reaching out to them. Trying to gain as much knowledge as possible!
Certified contractors are merely adjunct salesmen. Ask friends and family, someone in your/their circle knows a straight shooter.
State certified contractors have some merit.
They are directly supervised by the state with multiple inspections on every job.
And actual accountability to their customers!!
It only takes one unsatisfied customer to ruin you.
If a customer complains to the state board, that company has to resolve it to the states satisfaction or they will take your license away.
So a State Certified Roofing contractor has great merit.
Now a certified contractor from a shingle manufacturer
Like GAF or Owens Corning??
It doesnt mean squat.
That is just a salesman selling a lie.
Hoping you will only pay attention
To his super duper lifetime warranty…
You just cant ventilate this roof.
What i would do is install insulation on Top of the roof and then install metal roof on top of that.
Im confidant No heat will enter.
Use double bubble rolled insulation or some
3/4 inch 4x8 type sheets taping all the seams.
Make sure the screws are tested meaning they are exactly the right size to enter the 1x decking while only touching the very bottom of it and barely piercing through.
Maybe I should have clarified to say manufacturer’s certified shingle monkeys…
Put collar ties in it and install a good solar powered vent. Good place to run wiring for ceiling fans and lights. This could have been solved before it was built. If you want the ceiling to remain the same, coming to a point, sister a scissor truss on the whole thing. Install a good solar powered vent or if you prefer a powered vent.