Attic Ventilation Expert Needed - North NJ Area

 (Sorry about the last blank post, which was an accident.)  Anyway, my
problem is there is mold growing in my attic, primarily on the ceiling,
underneath the roof sheathing, and mostly on the side of the attic in which
the roof is facing the north.  I'm looking into getting the mold cleaned up,
but it seems to me I need to have the ventilation issue taken care of first.
A roofer looked at my roof, and doesn't think there are any active leaks.
My roof is less than 9 years old.

My attic is a crawl space that is around 1000 square feet in size, and I'm
guessing that it's maybe about 4 feet high at the center.  There are two
gable vents; one on the east side and one on the west side.  There are two
passive square vents near the ridge of the roof.  There is almost no
ventilation at the soffits, that is, my attic does not have soffit vents,
and, although there are a couple of little places where I can see daylight
near the eaves, this doesn't amount to much.

A roofer is talking about installing another roof vent with a temperature
controlled fan near the center of the roof near the ridge.   I'm just
wondering if doing so would be helpful,  or would it turn out to be no help,
or  problematic?  My fear is that the fan might just draw air inward from
the two closest vents, which are the existing square passive roof vents.  Am
I incorrect in suspecting this could happen?

My understanding, is that the consensus on the internet is that the state of
the art in attic ventilation is to have continuous soffit vents with a
continuous ridge vents.  Since my attic currently already has two gable
vents, plus two square passive roof vents. I'm just wondering if switching
to the ridge/soffit system would be the only real solution to my attic mold
problem, or if there would be a way to improve upon my existing ventilation
system (such as a installing fan).  Any ideas.  Basically I need to ensure
that whatever I have done ventilation-wise is going to be a real improvement
which results in mitigating the chances of mold growth.  Any
recommendations?

Thanks.

Jeff

  jeff wrote:

Gable vents and roof vent send the air where it's *not* needed;
the air bypasses the problem areas-the roof sheathing between rafters.

http://www.ronhungarter.com/ventilation_repairs.html

Jim

 Hi Jim,

Thanks for the reply.  Yes, I'm already aware that a continuous ridge/soffit
system is considered to be the state of the art.  However, since my attic
already has two square passive vents near the ridge, I'm wondering if there
might be another satisfactory, yet cost effective, solution to my attic mold
problem than simply closing off all 4 of my existing vents and altogether
switching to a continuous ridge/soffit system.

My attic is 1000 square feet of crawl space. Suppose I were to have a roofer
add, say 2 or 3 additional square passive vents near the ridge.  My roof
would then have a serious of, say,  4 or 5  square passive vents near the
ridge rather than having only 2 square vents near the ridge.  Now suppose I
also had the roofer add soffit vents, and I were to close off the two
existing gable vents.   Would having soffit vents plus a series of square
passive vents near the ridge function almost as well as a continuous
ridge/soffit system, or do you think my only valid option is to have a
contuous ridge vent installed?

Is there a way temperature or humidity-controlled fan-power vent could be
utilized to enhance my existing system, or should I stay away from a
fan-powered vent altogether.

Again, is my only valid option to have a contuous ridge/soffit system
installed or are there any other satisfactory yet cost effective solutions
(such as a series of passive square roof vents near the ridge combines with
soffit vents)?   My attic is roughly 35 feet long by 28.5 feet wide.  If a
series of square passive roof vents near the ridge would work well in
conjunction with soffit vents, then how many 9" vents would you recommend I
get installed?

Thank you, or anyone else for your advice.  Just out of curiousity, is there
anyone out there who disagrees with the idea that my gable vents must be
closed off altogether in favor of a ridge/soffit system?

Jeff

 <<A powered gable vent does nothing but suck air in from the ridge if both
types
of vents coexist.>>

Well, the roofer is talking about adding a powered vent near the ridge, not
at a gable end.  However, since there are already two passive roof vents
near the ridge, my fear is that the fan would likely cause the two passive
roof vents to suck air in and short circuit the benefit of the fan.

I'm thinking about having soft vents installed plus additional passive roof
vents near the ridge, and perhaps closing off the gable vents.  Would a
series of passive vents near the ridge work well in conjunction with soft
vents?    While I'm told a continuous ridge vent in conjunction with soft
vents is the state of the art,  since there are already two passive square
vents near the ridge, I'm wondering if simply adding more passive square
vents would be a sufficient yet cost effective improvement, as long as  I
also add soft vents.  If I do this, then is closing off the gable vents a
must?  What do you think?

Thanks.

Jeff

 

Just add more vents and don't close any of the existing ones.  You need MORE
ventilation and any more you can add will help.

Make sure you have enough soffit vents.

Adding a power vent with other roof vents and/or a ridge vent would still be
helpful.  That is a bunch of BS that it would be ineffective because it
would "short-circuit" the air.  You need more ventilation.  Any ventilation
would be good.  Any.