Attic space ventilation

[Robert J. Huska]

I'd like some advice on an inspection in regard to ventilation in an attic space where most of the 2nd floor is finished....2 BR, 2 BA....finished. There are about 6 unfinished storage areas behind kneewalls on both sides of the 2nd floor. There is also unfinished attic space above the finished ceiling. What I think may have been done is the original roof vented the attic space with a power vent because I saw pieces of one laying in the insulation. They just put a new roof on the home and installed a ridge vent. There is vented soffit, but it is completely separated from the space that is vented by the ridge vent. Is a ridge vent effective without the aid of vented soffit? Now, the only means of venting the 6 storage areas behind the kneewalls is the vented soffit, and the homeowner has insulation stuffed between each rafter. I'm not sure what to recommend beyond removing the insulation stuffed between the rafters to allow some means of ventilation to the storage areas. Sorry for the long explanation.

[Christopher Currins]

Remove insulation from adequate number of vented soffits. Install drywall, or baffles, at trusses. "Open" top of kneewall to allow intake air from soffit vents to exit at ridge vent.

[Kevin M. Leonard]

What Chris said only I call them rafter vents. http://roofing.owenscorning.com/home...raftrmate.aspx

[Kevin M. Leonard]

http://www.youtube.com/watch?v=Hbv45I_qs4U

[David A. Andersen]

Did we not already discuss this Robert?

Read about ridge vents. They require upper and lower vents to operate. Period.

As a matter of fact you can go look up some building code and find that there is a ration requirement between upper and lower vents.

The law of fluid dynamics states that for a fluid to move from one area to another there must be:

#1 A pressure difference.
#2 An opening for the fluid to pass through.

If you let air out the top of the roof you must replace that air.
If the air is rising because it is hot, the pressure is higher at the top, lesser at the bottom.

Where should the other vents be located?

[Jeffrey R. Jonas]

Maybe he just couldn't find the thread again... http://www.nachi.org/forum/f2/attic-...venting-64846/

[Anthony F. Miceli]

Yes, I couldn't agree more with everyone's opinion. Some people think stuffing the soffit vents with insulation is keeping the house warmer, not knowing they are creating more moisture to sit in the attic causing mold and wood rot.