Why you may need ridge, soffit, AND gable vents

Here’s a small bit on why I recommend leaving the existing gable vents intact, ( or even adding them ) when installing new roofing with ridge venting.
(link)Ridge vents and gable vents


As many have stated, ventilation is more theory than an exact science and you make a great case for your theory. Started reading through your blogs, you’re a pretty good writer, too. Send me a link to the front page of the blog, would ya? I’m interested in reading your opinions and theories.

Thanks S&G,

That link is the front page. Just got to scroll down to see the rest. :slight_smile:

I still only do what the manufacturer will warrant for the homeowner.

Everyone can do what they want but be careful - you do it other than what the manufacutre wants and you will be the one the homeowner goes after for wrong installationi per the manufacturers installation instructions.


Have you approached the manufacturers with your findings?

I agree that manufacturer ventilation specs could be more dynamic, for different situations.

Dennis, I agree with your findings and have said it before.

My house has the same set up and I have never had an ice dam…ever.

cool in the summer and no ice dams in the winter.

all of the ventilation theories are the manufacturers sales techniques.

I disagree.

the manufacture says i have to disagree :roll:


I don’t think it would make any difference.


I’m curious as to what you disagree with.


I understand. :cry:

Well dennis i respect you. You do damn fine work. But i have gone to seminars about the venting of roofs and not one of them agree with what you are saying. Im not saying it would not work im just saying that it goes against airvent and gaf. To be honest 70% of what i see is not ventilated correctly to begin with so whats the difference. Hey man pm me your number and ill chat with you. I got a bad cold that started today and well tired of typing already. chat with you soon.

Seminars put on by companies trying to sell a product or negate a warranty.

Seminars to educate those who don’t know what does or doesn’t work.

**Dennis **- explain to me how you would explain your theory to a homeowner who was just told his roof warranty is voided due to your theory by the manufacture.

In todays roofing market, we as contractors must follow what the specifications are and the standards set forth to honor the maunufactures warranty. I see your side of the story on this issue but have to disagree with it due to the fact of the manufactures warranty.

I would refer the customer to the warranty.

Such as this one by GAF on the exclusions relating to ventilation.


  1. Damage to shingles caused by inadequate attic ventilation or application of shingles directly to insulation or to an insulated deck unless prior written authorization is obtained from a GAFMC Guarantee Services Manager. (Ventilation must meet at least FHA Minimum Property Standards in the U.S. or building code requirements in Canada.)
    Note: Minimum net free ventilation area of 1 sq. foot per 150 sq. feet of ceiling area is required.
    When intake vents are located at the eaves and exhaust vents are located near the roof’s peak (in a properly balanced system)
    for maximum air flow, ventilation may be reduced to 1 sq. foot per 300 sq. feet.

or the Asphalt Roofing Manufacturers Association guidelines here



You are right about the vent they make a roof least a little long. I like the rages vent a little better.