# Proper venting literature



## AnyMonkey

I just had an interesting chat with a colleague at work here regarding installing ridge vents on an existing complex. He advised me that he was going to leave in the existing air vents and install the ridge vents as well. i told him this was wrong and he needed to take out the standard attic vents first and he did not agree. Although I am pretty sure my thoughts on this are right because of competing airflow problems I do not know where to look for literature on this. If anyone has a link it would be helpful.

Ken


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## shazapple

Depends on the size of the building. I've done some larger roofs where a typical ridge vent isn't enough and required a couple extra exhaust vents to make up the proper ratio and balance. In our local code it is identified as 1:300 vent ratio and splitting the venting between the top and bottom 50/50 ideally (maximum 25/75 one way or the other). As to where the code gets these numbers, I have no idea. 

This is of course assuming there are soffit vents. If not, then the ridge or exhaust vents are essentially useless.


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## AnyMonkey

shazapple said:


> Depends on the size of the building. I've done some larger roofs where a typical ridge vent isn't enough and required a couple extra exhaust vents to make up the proper ratio and balance. In our local code it is identified as 1:300 vent ratio and splitting the venting between the top and bottom 50/50 ideally (maximum 25/75 one way or the other). As to where the code gets these numbers, I have no idea.
> 
> This is of course assuming there are soffit vents. If not, then the ridge or exhaust vents are essentially useless.


 
I understand that sometimes you need standard vents at different areas of the home that can not be serviced by the ridge vents..... but I am talking about af 50s on the same area as the ridge vent..... anyone?


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## shazapple

I don't think the addition of square exhaust vents beside a ridge vent will short circuit everything; as long as there are soffit vents the hot air will still rise. 

Are the extra vents necessary? Not unless you have a very large building. If the building is wide enough from soffit to soffit, a 18sqin NFVA ridge vent isn't going to satisfy your requirements. If the building is small enough, the extra vents will throw off your 25/75 ratio.

I have had additional square vents installed along with a ridge vent in the past. The building was almost 80 feet from soffit to soffit, so the typical ridge vent wouldn't satisfy the venting requirements.


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## Grumpy

go to airvent.com


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## carlnwo

Yea airvent.com has some good info for you, they even have a support email address where you can send your query in and they will answer (just make out your thinking about purchasing the vents from them).


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