Attic Venting

[Gimesalot]

Newbie question here!

My DH and I are closing on a house within the next month.  I am reviewing the inspection report, to prepare to fix all the problems DIY. 

On the structure portion of the inspection, it states that there are only gable vents in the attic.  Do I need additional ventilation?  For reference, I live in New Orleans.  A hot sticky swamp in the summer, several days below freezing in the winter.

Thanks in advance.

[Greg]

The gable vents may be fine depending on their size.  1:150 to 1:300 are a couple of ratios to start with; 1 sq. ft. ventilation for every 150 sq. ft. of attic, etc.  In general gable end vents are not as good as the combination of eave and ridge venting, but your roof design may not allow it.

[Frankies Girl]

If you do end up needing a new roof any time soon, ask about retrofitting ridge vents. We did that on our house (Houston, so very similar humidity/heat situation), and it was pretty easy for them to do and didn't add a huge amount to our roofing bill but we have a very plain roof line with only two basic joins along the peaks. We originally had only soffit vents and a 1 motorized vent fan on the roof, which wasn't working and we had them remove, and there was a huge difference in our bills (and the house stays noticeably cooler in the summer) once we installed the ridge vents.

[Milspecstache]

A friend and me put on ridge vents when we redid my last house's roof.  It was easy and if I remember correctly (10 years ago) this is how we did it:
Lay out where you want them on the roof, measure out the width, then set a circular saw to cut the shingle and plywood only, and then cut it out.  Then we installed the vents.  Very easy way to reduce heat in the attic.  Could definitely do it at any time.

[phred]

my ridge vents flex, and are thus noisy, in very high winds.  My neighbor's ridge vents have blown off the roof in high winds

[Frankies Girl]

my ridge vents flex, and are thus noisy, in very high winds.  My neighbor's ridge vents have blown off the roof in high winds

Mine made it through several bad storms - including a category 3 hurricane with no issues. I would think that in hurricane zones (like New Orleans) the roofers would be savvy about locking stuff down.

[Spork]

I've had reasonable luck with the little whirlygig vents.  And mine made it through the edges of a tornado.  (Not the vortex, but the monstrous storm that accompanied it with pretty significant straight line winds.)

Of course, with these or the ridge vents, soffet vents are still needed.  I'm not sure how that will work with gable vents.  I would think even gable vents would need some sort of soffet ventilation. 

[phred]

yes, soffit vents needed with gable vents