Ridge vent question

when ridge vents go on a roof it is obviously assumed that there are already cuts in the roof ridge for the conra vents to cover? when one makes a ridge from scratch,how is are the cuts done? what does the cut look like and how wide should it be?

cut with a circular saw about 1 1/4"- 1 1/2" on either side of the ridge

so 1 1/2 inch wide? how long should it be if the ridge is 45 feet long?

The cut goes the entire length of the ridge, except maybe 1’ on each end for the overhang.

Most houses in my area have ridge plates,a 2x8 that runs the length of the ridge that the rafters are nailed to,if this the case you will need to cut about a 1 1/4 off of each side from the plate,and generally I stop about 18" from the ends ,no need to cut out where the over hang is ,just for the attic space.

yeah the 2x whatever runnin down the ridge makes it harder.
i only cut it about an 1" on each side when i have the 2x in the way. you dont want to cut to wide , cause there wont be much left to fasten vent.


Each ridge ventilation manufacturer has their own specifications on how wide to cut the slot. They can vary between them.

They also have different instructions if their is a ridge board in place.

My answer is that I would follow the manufacturers written specifications, so that I would not compromise the warranty.


so you are basically cutting a lon horizontal from ridge edge to ridge edge but stopping about 12-18 inches short of the edge. the line you cut is about 1 1/2 inches wide from the top of the ridge? so basically the cut is on the side of the ridge?

the cut is on both sides of the ridge

I stop cutting at the last rafter and leave the end solid.

rooferscoffeeshop.com/show_a … le=921&s=0

I forgot to mention something VERY important. I always set the saw bevel so the blade is vertical to the ground. Even undercutting a full 45 does NO harm, and increases the overall vent area.
NEVER cut ridge with the saw set at it’s 90 degree position if the roof has any pitch to it. I’ve seen that done and it left 1/8" cutout for venting.

every hoyse with an attic basically has a ridge vent already? unless its new construction of course?
only a vent if their is an attic, has to be an attic for a ridge vent?

[quote=“taser”]every hoyse with an attic basically has a ridge vent already? unless its new construction of course?
only a vent if their is an attic, has to be an attic for a ridge vent?[/quote]

I’ve only counted 4 or 5 ridgevents in my neighborhood,but they seem to be replacing powervents because they dont burn out and use electricity.Read this … roofing.com/forum/about5919.html

so ridge vents are only needed for homes with attics?
it seems from what you guys are saying is that the vent is cut on the side of the roof ridge and not the top of the ridge?

Ridge vent slots are cut in BOTH sides of the very center of the ridge. Think of the letter A - take out (on average) 1" of the very top of the slopes.

Keep in mind that not all roof pitches will accept a ridge vent. If you are under 4:12, ridge vents are not a good idea & I am not aware of any mfg. who has a ridge vent that will work for 12:12 or more.

The basic idea is to remove the very top of a roof, i.e. where the hot air will naturally rise to, then put a ‘mini roof with side drafting slots’ on it, & place shingles over this new mini roof.


All houses should have venting.
The type of venting depends upon the construction of the structure.
Ridge vents are most common in my area.

Why do you simply refuse to tell us why you are asking all these home improvement questions?
We can be of more help if you would share this with us.
I mean, you are on a roofing site asking about screens, windows, and doors… :roll:

Mobile homes or vaulted cielings with next to zero trapped air are not always the best candidates for ridge venting because they usually have no attic spaces & are almost fully filled with insulation.

I hope you read ALL the specs on RanchHand’s last diagram. He pointed out that the saw depth IS critical! I forgot to mention it.

Sorry about that, but some things are SO second nature, we don’t consciously think about it, and have trouble consciously REMEMBERING it when telling somebody how to do something.
And sometimes. when somebody asks me why I insist on doing something a certain way, I can’t recall why, but I KNOW not to do it differently. And I’ll remember why within 2 weeks when I look at somebody else’s roof to find a leak.