Will Ridge Vents Work?


#1

First off, let me say that I’m a first time homeowner with absolutely no knowledge of roofing…so bear with me. :mrgreen:

We’ve begun taking estimates to have our roof replaced and I’m confused as to what work to get done. I was told by our first bidder that we need a ridge vent. I’ve never heard of ridge vents but after doing research, I like the idea of one and it was only $350 extra. Also, this roofer said with ridge vents, we wouldn’t need our attic fan, which also needs to be replaced.

However, I’ve received conflicting information. My neighbor, who’s in construction, said a ridge vent won’t work because my 1976 split level home doesn’t have soffit vents for airflow. Our roof doesn’t have an overhang so there’s no room for soffit vents. We just have vents on the side of our home as ventilation. I’m thinking hot air rises and that’s a good thing. Neighbor says it’ll create stagnant air below the vents…that makes sense too.

So my questions are:

  1. Will a ridge vent work in on my home?

  2. If I get a ridge vent, do I need my attic fan?

Thanks for any and all advice! Glenn


#2

A ridgevent is very desirable, necessary even…
Your neighbor is correct, you will need intake (soffit vents) for it to work.
There are a couple of products on the market that can fix your soffit venting problem.
One is called “smart vent”, I have never used this product myself but other knowledgeable roofers on this site swear by it.
There is also a vented drip edge that can be used.

Your roofer will need to fix your soffit venting problem in order for the ridgevent to work.
We do this all the time…
If your roofer is unable or refuses to fix the soffit issue find one that will.
It *usually isn’t that hard.


#3

Along with what was said. If there is enough ridge to allow ridge vent. Alot of contractors for somee reason do not do the calculations to ensure proper ventilation. Without soffit vents the ridge will not work period.


#4

Depends on your situation. If you have a problem relating to inadequate ventilation, then a ridge vent may help.
A vapor barrier, adequate insulation, a light colored roof, etc., are things to consider before ventilation.

"Without soffit vents the ridge will not work period.“
Probably meant to say, " will not work as well” . :smiley:


#5

No i still say without soffit vents 2 things happen when using ridge vent.

  1. the roofs warranty is void period.

  2. the ridge vent does not work without an intake source.

If a roof is not correctly ventilated you void all shingle warranties. You CAN NOT mix exhaust vents its either a power vent, cans or ridge vent. Not all of the above or whatever. Dennis you know i have done the seminars and i do what im talking about not saying you dont. But 1 thing is for sure. The only shingle with a inadequate ventilation will give you a warranty and thats 10 years from certainteed. Aside from that if something goes wrong and roof fails your on your own. Just did a warranty job tooday.


#6

[quote]"Without soffit vents the ridge will not work period.“
Probably meant to say, " will not work as well” . Very Happy[/quote]

The original wording is more accurate.


#7

Come on GTP, I know you know better than that. You need to add some qualifying statement to those remarks rather than just give such a blanket cover all answer.

Regarding the shingle manufacturers warranty, it is based on the total amount of ventilation, but recommended that the equal or slightly greater amount be from the soffit or intake ventilation system.

Calculations for the total NFVA and for the size of the attic floor space dimensions are required to properly conclude whether or not the system will meet or beat the total NFVA required by the manufacturers.

Yes, it will work more efficiently with a proper amount of intake creating a “Flowage” of air “Washing” through the attic chamber, but by only having one system in place does not necessarily mean it is not enough to meet the requirements.

The ridge vent will still exhaust hot air by the “Stack Affect” and Thermal Buoyancy, wheras heat will rise and eventually will be exhausted from the ridge vent.

Now, for the OP’s 2nd question;

You can install an intake ventilation system. There are 2 well known products on the market.
1st is the Smart Vent by DCI Products, Inc.
2nd is the Eave Drip Edge Vent, by the Air Vent Corporation.

They both work for intake, but I prefer the Smart Vent Product, because I use it continuously and have done so for the past 5-6 years, with no adverse affects and extremely posititve results.

Although your neigbor in the construction business has a moderate basic understanding of ventilation, sometimes a little knowledge can be harmful.

Also, insulation R-Value and the vapor barrier suggested earlier are important as well.

Ed


#8

That “stack effect” your talking about rarely works.

As the air warms it expands, beyond the capability of the ridgevent to exhaust it…
If there is no intake.
In order for the air to leave the attic space there has to be air to replace it.
Where does this air come from in your theory?
If it is coming from the gable vents it is not venting the eaves properly.
Don’t get me wrong, a ridgevent with no soffit vent will exhaust hot air, just not enough, in the right places…


#9

[quote="-Axiom-"]

That “stack effect” your talking about rarely works.

quote]

As an example, consider a 2 story cape cod house.

I am only speaking of the interior for the sake of an illustration.

No widows open and no whole hose fan or exhaust ventilation.

Walk up the stairs. It gets progressively warmer and warmer as you climb higher up towards the top.

There was no intake ventilation in this scenarrio, but if you ever walked into a home, surely you would have noticed this obvious and dramatic change in temperature.

Heat rises. It causes other items to expand, and in a sencse, I guuess that you are correct that the aire expands too, because the molecules are more excited and less dense.

Or, use Air Vents example from their video or DVD. Observe a hot air balloon. Insert heat into the balloon and the entire carriage and balloon rise due to weighing less than the exterior unheated air.

Did I make that clear, or do you have an opposing illustration which could caue me to reconsider the thermal dynamics of hot air and ventilation?

Ed[/quote]


#10

I just think that you are forgetting the fact that the exhaust for the air is restricted and currently there is no intake.
I am well aware that hot air rises, hence hot air balloons.
A hot air balloon is not restricted by the air above (or below) it so it can rise.
The air we are speaking of is caught inside a roof and can only escape through a 2"- 3" slot.
In order for this air to leave the attic space there must be air to replace it (from somewhere) or there will be a vacuum.
This air must come from somewhere, where does it come from?


#11

Although flowage will be impeded, we do not have houses that are built to a true air tight condition, especially regarding the top wall plate where it meets the attic floor. Additionally, ther is permeability through the housing product and many non-realized holes throughout the cieling and wall systems in place.

I saved a very well illustrated article which discussed how to build a truly tight home to enable the elimination of attic ventilation all together. In this artice, it mentioned and pointed out in real world illustrations, where so much of the interior humidity and heat loss occurs to proceed uninhibited into the attic.

In a truly air tight building, your point would be more valid.

Ed


#12

Consider a jar with a bug inside.

Screw on a tightly sealed lid and the bug dies.

Poke some holes in the lid and the bug lives.

or

Turn a jug of water upside down with the cap off and watch the water come out.


#13

That reinforces one of the first points I made.

The water does come out.

But, if there were a vent hole on the opposing side when it was turned upside down, it would flow out much more freely.

Thanks for backing up my point.

Regarding the bug, should I report you to P.E.T.A.?

Do you actually do such things to insects? Of course they die, they have been deprived of oxygen.

Ed


#14

[quote=“dennis”]
Turn a jug of water upside down with the cap off and watch the water come out.[/quote]

thats because the mass of water is greater than air and combined with other forces such as gravity…whats in motion stays in motion…for every action there is an equal and opposite reaction…what is this 8th grade science…hahaha…i cant deal with this subject any longer :?
[size=150]any more questions?[/size]


#15

marshallext,

The point illustrated relates to pressure, not gravity. The water, a liquid under pressure, is replaced by air, another liquid. I don’t expect you to understand. But the poster and others will.

Ed,

"Regarding the bug, should I report you to P.E.T.A.? "
:smiley:


#16

actually i could care less and just wanted to bust your cahonnes…but i thought air was a gas?


#17

So did I, although their are some components of water that make up its composition.

Ed


#18

i thought there were components of air that made up water: 2 parts hydrogen,1 part oxygen…now im confused…thanks guys :?


#19

You guys are making this way too complicated.
In order for air to go out air has to go in to replace the air going out…
if there is no air coming in and only going out you have a vacuum.
Nature will not let this occur.
Rather simple actually.


#20

An attic structur is not a tightly close sealed off air space.

There is no potential for the vacuum theory to facilitate itself. The air WILL be drawn in from the leak prone areas I mentioned previously.

Good Night,

Ed