gable vents

[mcjk]

i am building a new house and plan to use gable vents to vent the attic. do i also need roof and/or ridge vents?

[Jay11J]

Check with your local codes. For sure you will need roof vents. also sofits.

[notsohandy]

mcjk: I'm not a repairman, contractor or anything -- I'm just relating my practical experience as homeowner. What I have learned is that the more attic ventilation the better. (Of course it depends on the climate in which you live.) But generally speaking (and "experts" agree) keeping your attic ventilated and cool in the hot summer is important. Yeah, I know heat rises and all that, but I also discovered that all that a lot of that searing summertime heat trapped in the attic ALSO has a strong tendency (in the late evening) to start seeping down from the attic and into your living space. This causes your air conditioning system to work much harder in order to satisfy your comfy thermostat setting.

After going up into my attic on a hot afternoon, I realized it was a virtual oven up there. I had some soffit vents (vents in the eaves or overhangs), but discovered they were partially blocked by all that goofy "blown" fiberglass insulation. I also had gable vents, but the screen mesh which covered them (to prevent insects, birds, etc. from getting into the attic) was clogged with dust which hampered the free air flow. So, I had gable fans installed to draw out the hot air. I also installed those inexpensive turbine vents (the kind you see spinning around and around on some roof tops). Consequently, my attic is now about 50 degrees cooler. It's only about 90 degrees up there now compared to the 140 degrees it used to be. My air conditioner labors a lot less and my electric bill is about 30 percent lower.

Those turbine vents are effective, but in the winter time they should be covered to prevent the warm air from escaping. I cover mine with covers I get at Home Depot or Lowe's. I cover the gables with plastic sheeting. It's all a bit of a hassle, but well worth it.

Well, that's my two cents worth. I hope the time it took to read this post was worth it. :blah: :blah: :blah:

[Ed Imeduc]

For sure foget any turbine vents they have been outlawed down here, Gable vents are just fine and the strip vents in the over hang. Also think power vent fan in one, on a tstat. Now for the attic you need 1sq ft for every 150sq ft of attic vents with 1/2 in and 1/2 out. Dont forget to use the foam rafter vents so air can get up from the over hang up over the insulation to the attic for the vent fan in the attic. Go attic sq ft X 0.7== the fan CFM for up there.

ED thats no :blah: :blah:

[notsohandy]

Ed Imeduc, why are turbine vents outlawed where you are located? I'm very curious. Is there something hazardous about them that I don't know about? It would be interesting to know if there's somekind of problem with them. Thanks. :confused:

[Ed Imeduc]

For sure : First they do leak rain in a lot. Then if you look when its real hot out and you do need them they dont move as there is no wind. So they dont do any good. Then the hurricane's took them off along with the ridge vents that let rain in also. Some blowed off with winds only 45MPH.
like you said: We tell people that the roof is there to just keep the snow and rain off the insulation is all so its like a big tent let all the air in you can.

ED ;)

[lynn comstock]

Building a new house? Check the information at http://www.eeba.org/technology/dumbsouth/default.htm

#10 is on attic ventilation. His recomendations are sometimes called a "Cathedralized attic". If you want the science behind it go to
http://www.buildingscience.com/resources/roofs/unvented_cathedralized_attics.pdf