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We are being encouraged to use end-gable vents rather than a ridge vent. Supposedly the cost is the same. Is that true? And which one works better, or does it really not matter?
Thanks
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I am no expert (there are plenty of them here, though), but what I understand is that ridge vents (like cor-a-vent) are better because they allow air flow from the eaves straight up to the ridge under the roofing material and keep the entire roof cooler, preventing shingle damage in the summer and ice dams in the winter. Gable end vents cause short-circuiting of the air out the ends of the roof and the middle will get warm and cause problems. Of course, there are those that say dont vent at all, but I believe the UBC requires 1/300 of the floor area as vent area, split evenly between eave and ridge or gable (as do a lot of shingle warranties).
*Alana,I agree with what Sami says. I am no expert either, but I would certainly go the ridge vent route. May be that your builder doesn't want to do it because more labor is involved in installing them. I am in MN and rarely see homes built now with gable end vents- when you think about the dynamics of convection they don't make any sense. Remember to have chutes installed inside the attic between the trusses so that your insulation doesn't block the soffit vents.What is your climate? Are you in a very windy area? What is your roof design, pitch, etc. All play a factor.Attic venting is a huge topic and is worth some research...Best of luck-Brian
*I'm no expert either, but I've read several articles and all confirm that ridge vents are superior.
*It is my understanding (and I have no experience at this) that the ridge vent without the soffit vent is pretty much worthless. The gable end vents aren't supposed to be much good either, butb maybebetter than the ridge vent without the soffit vent.You should do a search or browse through thei Energy: Heating, Insulating, & Venting a Housefolder. There has been a lot of discussion about this .Rich Beckman
*Your right Rich. It's the soffit ridge combo that kicks the booty. Especially important in well insulated houses in areas with alot of humidity (where there are not many swamp coolers running in the summer).Same goes for uninsulated crawl space cross ventilation at least for a part of every year.Good Building,Jim Malone
*Alana. Ridge vents MUST be installed along with soffit vents. However, what everybody ignorers--or doesm't know-is that not all combinations of ridge/soffit vents work. Anm where in the soffit the soffit vents are located is equally important.Go to your library and aske them if they have a copy of Complete Building Construction, 4th Edition. Read the Chapter on attic ventilation. You'll fins answers to your questions in that chapter. GenerL
*Don't let them put the gable vents in. Occasionally around here, they want them in for architectural reasons. We don't even bother to cut holes for them.A gable vent will often create an unwanted negative or positive pressure thereby rendering the ridge and soffit vents ineffective. blue
*Good advice above. Also, another disadvantage to gable end vents is that they can admit wind driven snow or rain... you don't want water in your attic, do you?To learn more, go to this web site and scroll down and then click on b Principles of Attic Ventilation and once there scroll down and click on b Section II - types of attic ventilation.There is a bunch of text, but if you scroll down, and look at the pictures, you will understand why gable end vents are not the first choice.
*Alan, It's unanimous. Go with the ridge/soffit combo. If the area is to be used as living space, channels need to be installed under the roof sheathing the length of each bay, thereby connecting the soffit with the ridge vent. When the roof is then insulated, care should be take not to crush the channel as they are often made of inexpensive styrofoam or other lightweight material.
*Tony:I don't follow ya buddy... If she was talking a cathedral ceiling she wouldn't be talking about gable end vents????? Insulation baffles may likely be necessary at the eves, but that's it.
*So, if the soffit/ridge vent system is best why is the contractor pushing the gable end vents? Most likely ignorance. But, some builders like them because it makes roof cavity access easier. So, ask him if that is the case. If so let him vent properly and just put a solid access door in the gable end.Whatever you do please make sure you have good access to the roof cavity. You Will need to get up there a lot more than you think now.
*Matt G.,... Scissor trusses create a possibility for vaulted ceilings and gable vents. Maybe that's where he was coming from. Also, not all attic areas are designed to be finished...
*Points well taken, and with a cathedral ceiling I don't see any other way, although I don't like the looks of a ridge vent. I would point out that a website sponsored by an insulation company (that makes the baffles that go from soffit to ridge) has a natural inclination toward soffit/ridge venting - it gives them a chance to sell i twoof their products.With a conventional flat attic in more traditional construction, I prefer gable end vents. You can augment them with soffit vents if you want, and they can be done well. For instance, on a house I am working on (bids due today), we have gable end louvers and soffit vents, the latter are set between pairs of victorian brackets (matching original) to limit their visual impact.Additionally, you can set a thermostatically-controlled attic vent fan i behinda gable end louver and have one less *^$#@ roof penetration. If you are concerned with wind-driven water, what I usually do is remove the screen from the louver (usually fiberglas so replace with aluminum) and add a short-leg aluminum channel to the inside top of each louver blade as a windscreen - this forms a lip that stops drips from being blown directly up into the opening.So I'll be a pain and make it i notunanimous - I prefer end louvers to ridge vents.Jeff
*Matt, Are you saying I should actually READ the posts before I reply. This is what happens when you take too many hammer shots to the head. Thanks for the correction.
*Tony:No problem. Sometimes it's a bit hard to read between the lines on these questions.Avoid those hammer shots, and definately, keep your arms out of the way of that chop-saw (see other thread)!!!
*Jeff, I've seem snow piled up below gable vents in my first house. I really don't think they work properly in many situations. The air comes in them and out the cans or ridge.blue
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We are being encouraged to use end-gable vents rather than a ridge vent. Supposedly the cost is the same. Is that true? And which one works better, or does it really not matter?
Thanks