Adding more insulation to attic

They are insulated with the standard roll fiberglass insulation from whatever code was 15-20 yrs ago. That's also why I was asking about how much to install. I know there is a transfer through the walls and don't want too much but don't want to less either.

 

Ridge gable and soffit vents? Strange combo.

 

Should be ridge OR gable , plus soffits

 

Yes! That's why I have always wondered cause everything I've ever seen you didn't use both, just one system or the other.

 

Exactly! I'm wondering if that is screwing up the air movement and making the situation worse.

 

Good info here about attic ventilation.....

http://www.servicemagic.com/article.show.5-Myths-about-Attic-Ventilation.16547.html


http://www.peaktoprairie.com/?D=206

 

Both certainly won't hurt, thought it might be overkill in the winter, but in the Georgia climate I can certainly not disagree with as much outflow capacity as possible.

The two systems are not "fighting" each other any more than adding a couple of "whirlies"

 

Everything I've been taught is that if you have good soffit venting for intake , you should have either high gable vents OR ridge vents , but not both ridge and gable as the convection current is not as efficient if air can be drawn in the gable end vents

 

Except intake and exhaust should be roughly balanced at soffit and near the ridge to promote an efficient convection current

 

how thick is the blow in you have now?

 

It's about 8-10 inches right now or 203-254mm.

 

Ahh... didn't think about the gable functioning as an intake.

 

yup pretty much. I know about the ventilation through the ceiling and such into the attic but you lost me with the walls. I'm guessing same thing, moisture and such is also moving from the cooler part of the house into the attic through ceiling and walls and rising up the walls into the attic basically?

 

Yup, gotcha! Screwing with the airflow.

 

Is it a continuous ridge vent or cans ?

 

you'd have a R 30-35 now, less if it's been compacted. I believe standard (around here anyway) is a R 40 in the ceiling.
are your exterior walls 2x4 or 2x6?

 

No... I was referring to radiant heat (not head) passing through the walls.

2 in the afternoon, walk around and feel the insides of your exterior walls. You might feel a difference in temperature between opposite sides, but it should not be a huge difference.

It would be really nice if we COULD channel hot air through the walls up into the attic before it penetrates the drywall... but that's against fire codes.
In addition to insulation, you have firebreaks in the wall bays that will slow the progression of an electrical fire from the baseboards up into the attic, plus the wall header which seals the wall bays from the attic.


The black roof is not doing you any favors. Does your HOA (if you have one) allow light gray? I have a flat roof, and my cooling bill dropped about 20% when we went from a red gravel to a white polymer material.

 

continuous. Entire ridge line.

 

1" of exterior XPS styrofoam insulation FTW , eliminates thermal bridging through the studs

 

I would try blocking off the gable vents and see if that improves the situation , you need to make sure the air from the soffits can get into the attic and is not blocked by insulation , styrofoam of cardboard baffles are generally used for this purpose