I have been experiencing some moisture in my attic this year and would
like to get some advice on how to solve the problem.

What's in my attic:
- The attic has a continuos ridge vent with continuos soffet vent along
both eaves. The vents seem to be working and there is no insulation
blocking the soffet vents.
- The attic floor is well insulated with R30 insulation w/ an attach
vapor barrier facing the attic floor.
- My drop-down attic stairs has a battic door w/ insulation so there
shouldn't be any heat leak though the opening.
- The bathroom fan is vented through the soffet vent and no air is
escaping in the attic
- There is a gas hot air furnace in the attic which had some leaking
duct work. The leaks have been fixed and some additional insulation has
be added to the ducts.

I thought by fixing the leaks in the ducts, my problem would be solved,
but the North side of the roof still has some moisture. It is a two
story house located in eastern MA. The house does not have a lot of
humidity (usually around 30 - 45%). and the attic is definitely cold.
It has been a rather damp winter in the Northeast, maybe that has
something to do with the problem.

The only options that I can think of a

1. Add an additional vent where the furnace is located just in case
there is some small heat leaks that I missed. (If I do this, I'm
worried that this would affect the airflow for the ridge vent)
2. Install an Attic Fan w/ an Adjustable Thermostat and Humidistat with
the idea that the humidistat would detect moisture build and vent it
out. Any suggestions on what the humidistat should be set at (I'm
thinking 45 - 55%)

Please let me know if anyone has any suggestions on something else to
check in the attic, or what you think of my options and which one would
work the best.

thanks in advance

Moisture must be coming from somewhere- either furnace or interior of
house(I'm assuming no leaks from outside). If furnace, check for leaks
again. No blockages in exhaust ducting/ chimney? If from inside of
house, you would probably see darkened areas on ceiling of 2nd floor,
condensation from where warm, moist air encounters gap in attic floor
insulation. Moisture is definitely inside attic, yes? North side of
roof could certainly show signs of moisture(eg lichen/ mildew) on
outside- put zinc strips under shingles for this.

"The attic floor is well insulated with R30 insulation w/ an attach
vapor barrier facing the attic floor. "

Facing the attic floor or facing the ceiling of the living space below?
The vapor barrier should
be against the ceiling of the living space.

thanks for the reply...

There is no signs of moisture on the second floor ceiling. I'll check
the furance again, the only thought that I have here is that there is a
grate around the steel chimney for the furance that was tar'd over this
summer due to rain leaking in. I didn't think it would make that much
of a difference given that I have a ridge vent.

The north side of the roof looks ok, no signs of mildew. There is some
black along the soffet vent on the north side, maybe the moisture is
coming in from here. It has been a very warm and rainy winter.

The vapor barirer is facing the attic floor...thanks


wrote:
"The attic floor is well insulated with R30 insulation w/ an attach
vapor barrier facing the attic floor. "

Facing the attic floor or facing the ceiling of the living space below?
The vapor barrier should
be against the ceiling of the living space.

Living in SW CT, I can tell you that your RH is too high, IMHO. Keeping
humidistat @ 25%, windows in some unheated rooms just start to show
condensation. (double-pane, low-e, of course.)

With that RH, small leaks into attic from room(s) below could easily
cause your problem. Poorly taped drywall joint, minor gaps here and
there, and the mold is off and growing. Previous owner of my house had
one small series of gaps in ceiling, maybe totaling 1 sq inch- provided
growth media for various green and black flora. (And ... for a list of
reasons, their impact on the inside RH was purely random.) Even on
inside of roof deck, you could see evidence of condensation, on most of
roof.

HTH,
J

To get mold alot of air is leaking, a blower door test apx 300 will
identify alot of your issues except furnace which still likely leaks. R
30 is probably under code for your area and definatly not optimal,R 60
may be fo you area-zone. Air can leak in outlets, foam insulation covers
are cheap, up through walls from the basement etc. You may be under
ventilated there are vent size per sq ft recommendations you need to
research, a power vent will just pull out heated air. Your attic door
may not seal, there are alltypes of sizes available, A blower door test
woul eliminate most everything.

Thanks for the Replies....

I don't believe that the RH level in my house is the issue, there is no
condensation on any of the windows. Also, I open the second floor
windows each morning to let the humid air out from running the
humidifers in the bedroom at night. I'll check for any gaps but really
haven't notice any in the past seven years.

A blower door test sounds like a good idea. The Attic Door has a tight
fit and there is an insulated cover over it and all my outlets have
foam cover.