PROPER Ventilation????

Starboyz66ftp

i have heard so many opinions on proper attic/roof venting, i don't know what right anymore, combination wise, soffit and ridge only, soffit and box vent only, soffit and gable with no roof vent??? what are proper combos???

Teetorbilt

Star, you just opened a can of worms without telling us where you are. I have ridge, soffit and gable end vents which is very unpopular with the roofing crowd. I later learned that the gable end vents are to relieve the pressure during hurricaines, I've been through 3 in the last 2 yrs. and the system must be working. The roof is still there.

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AaronB.

You need one square foot of net free vent space of exhaust as well as one square foot of net free vent space of intake for every 300 square feet of attic floor space, passive ventilation only.

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River Rat Dad

AaronB's suggestion comes out to a ratio of 1:150. I would agree that more is better, AS LONG AS AT LEAST HALF IS INTAKE FROM THE EVES.
Some roof designs make balanced venting nearly impossible to achieve.
I think that in most cases a 1:300 ratio is OK as long as there is a vapor barrier under the insulation and half the venting is at the eve.

Grumpy

Ventilation is a science unique to the architecture of each building. While the forumulas for determining the volume of necessary ventilation are the same for each attic, the type of ventilation varies. Mushroom vents work great on some roofs while ridge vents are better on others. It all just depends on the architecture of the roof lines.

River Rat Dad

I have nothing more to add...except not to let Grumpy have the last post...

AaronB.

Actually, the 1:300 ratio formula also calls for 1 foot in and one foot out...a balanced system.

__________________
http://www.roseroofing.net/
Seamless Industrial and Commercial Roofing Systems, Residential Repair. For Those That Demand Quality!
Free roof inspections within 12 miles of our locale.