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Attic Fan vs. Ridge Vents

Post in 'DIY and General non-hearth advice' started by Vic99, Aug 1, 2008.

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  1. Vic99

    Vic99 Minister of Fire

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    I live in a 1920 Dutch Gambrel, 2 story home. I have a fairly small attic, 700 cubic feet, very steep roof, shingled. Gets real hot up there in the summer. Floor of the attic is insulated with fiberglass to R-38. Nothing is stored up there.

    Would ridge vents or some other kind of venting suffice or would I need an attic fan? If I go attic fan, I'll probably go solar, but if vents do the trick, no need in making things more complicated. My main goal is to cool the attic to save on AC.

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  2. Redox

    Redox Minister of Fire

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    Ridge vents do an amazing job with no energy input. I helped a neighbor install one on his house and he noticed that his attic fan just didn't run after that. Just make sure you have enough air intake under the eaves. Perforated soffiting is ideal.

    Chris
  3. Hogwildz

    Hogwildz Minister of Fire

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    Redox has it right.
    Ridge vent is passive venting. No electric, no fan to break down, free ventilation.
    For a ridge vent to work you will need soffit venting so the cooler air flows in the soffit vent at the eaves as the hot air vents out the top at the ridge.
    Get a good shingle over mesh brand. Cobra vent is good stuff. The metal stuff you just nail over the top is garbage. Make sure you cut the proper amount of decking & roofing awat from the ridge pole at top. NOT TOO much either, or the ridge vent wont cover it.
  4. Vic99

    Vic99 Minister of Fire

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    Great. Assuming a proper install, any drawbacks such as moisture, mold, etc. to which I might have to pay attention?

    Should I block the ridge vent in the winter when I heat my house?

    Thanks.
  5. Adios Pantalones

    Adios Pantalones Minister of Fire

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    A proper ridge vent and soffits will reduce chances of mold and moisture, as air flow will carry it off. The same reason when you throw a tarp over a tent as opposed to a proper rain fly, it fills with condensation. Not that it ever happened to us out hunting in freezing weather though, eh?
  6. Vic99

    Vic99 Minister of Fire

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    No, never happened.

    Not even once.
  7. Hogwildz

    Hogwildz Minister of Fire

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    Nope the part of the reason for the venting is to have air moving constantly. Keeps moisture & such from happening.
    DO NOT ever cover the venting. Its just as important in winter as in summer.
    In winter it helps keep uninsulated attic space cooler in winter. Which helps keep snow melt & ice damning on roof from occurring. No ice dams, no snow & ice melt backing up under roof & coming in spaces its not supposed to.
  8. mikeathens

    mikeathens New Member

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    My old house didn't have any gable vents or soffet venting when I bough it. The partial cathedral ceiling underneith made it impossible to both insulate AND have soffet vents, so I installed gable vents in each end and a power vent in the upper north face of the roof. Definitely doing the trick, though it does use some power. I have to say that our upstairs rooms are several degrees cooler and the air conditioning (on the rare occasion that it is used) keeps the upstairs cooler than the downstairs. Used to be that the AC would run almost constantly, and the upstairs was remain hot all of the time.
  9. peakbagger

    peakbagger Minister of Fire

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    In high snow areas like northern NH, I recomend gable end vents and ridge vents as the snow will block off the ridge vent for quite a few weeks after a good snowfall. If there arent gable end vents, the air flow up through the soffits gets reduced and ice damming can appear. Took me awhile to figure out why my place didnt have that problem but similiar houses with only ridge vents did.

    One important thing about gable end vents, is to install a plastic lined tray inside the attic to catch any fine blowing snow that can sneak past the louvers and screen on the vents. It doesnt happen often but when it does, the snow eventually melts and makes a stain on the ceiling that people confuse with a roof leak.
  10. Hogwildz

    Hogwildz Minister of Fire

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    Good point, sometimes soffit & ridge vents are not possible. I hope that insulation in the cathedral ceiling is not right up to the underside of the roof deck. That could cause mold & rot from no venting.
    Seen it happen quite a few times. Thats where baffles are used to hold the insulation a few inches from the underside of the roof decking, to give the air a place to move. Another thing to keep in mind. A complete cathedral ceiling with the roof rafters enclosed by roof deck up top & drywall or wood on underside, will need the baffles soffit & ridge, gable vents will only vent the end run and thats all. Not saying thats your case, as it appears you have noticed lower temps. I am guessing you have trusses that let venting go between them.
  11. mikeathens

    mikeathens New Member

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    It's old school rafters w/no ridge board. Unfortunately, the insulatiion IS right up against the roof decking, with pine T&G;below. It looks nice now, and I figured that when (if) the thing rots, I'll be ripping everything off and doing it the right way with way more insulation. Otherwise, I am looking at major expenses right now.
  12. Hogwildz

    Hogwildz Minister of Fire

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    Actually you will be able to get away with tearing the roof shingles & decking off, and leave the tongue & groove. Replace any moldy insulation if needed, and add the baffles on top and lay the new decking on and re shingle.
    Not super easy, but not all that hard, just time & tedious. Of course plywood aint cheap either. But the plus side is you won't have to tear any of the tongue & groove off. Unless you wanted to.
    I can almost guarantee some of the underside of that decking is black and rotting. Not sure how your going to add more insulation if its already up to underside of the roof deck. Unless you tear the tongue & groove off & lower the ceiling. HOpefully when ya git to it, it won't be as bad as expected. :)
  13. richg

    richg Minister of Fire

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    Yup, ridge vent and soffit vent. Get the rigid plastic vents, which go by the name of "Snow King", instead of cobra roll. The roll can compress over time, and can be compressed if you nail too tighlty.
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