Protecting bathroom fan from attic cellulose insulation
Alfred K.
insulation (cold climate!) is blown cellulose particles. Is it
customary to cover the fan's top housing with some kind of a cap to
protect it from being contaminated with the insulation dust?
Tony Hwang
The exhausted air should go outside thru insulated duct. How come are
you worried about dust?
Wayne Boatwright
You should *not* be exhausting bathroom air directly into the attic. There
should be a duct (preferably insulated) connected to the exhaust fan and
connected to an appropriate exterior vent through the roof, eave, or sidewall
of the house. This would also apply to exhaust fans anywhere in the house;
e.g., utility room, kitchen, etc.
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**********************************************************
Wayne Boatwright
ransley
Vent moist air into an attic and it will be black with mold fairly
quickly. Then follows rot, vent it as they all are supposed to be
done, outside.
John Grabowski
"Alfred K." <iris@v_isi.com> wrote in message
news:mn.0d887d9a3...@visi.com...
*No it is not customary, but not a bad idea.
Alfred K.
>
>> An exhaust fan has been added to the upper floor bathroom. The attic's
>> insulation (cold climate!) is blown cellulose particles. Is it
>> customary to cover the fan's top housing with some kind of a cap to
>> protect it from being contaminated with the insulation dust?
>
> You should *not* be exhausting bathroom air directly into the attic. There
> should be a duct (preferably insulated) connected to the exhaust fan and
> connected to an appropriate exterior vent through the roof, eave, or sidewall
> of the house. This would also apply to exhaust fans anywhere in the house;
> e.g., utility room, kitchen, etc.
An insulated duct, of course, is there, connected to an ridge vent on
the roof. I am asking about some possibility of contamination even with
the duct present.
hr(bob) hofmann@att.net
EXT
No, you won't get contamination. However, I find it actually contrary to the
building code in regards to vapor barrier sealing, that most manufacturers,
even high priced ones, have many holes, opening, gaps and other areas that
water vapor and drafts can easily get through. When I install such fans, I
always cover every hole, opening and joint with metalic duct tape on the
inside and outside of the housing. This gets as close as possible to a good
vapor barrier and prevents the fan's vacuum from pulling insulation dust
into the housing and drafts from entering when the fan is off.
Wayne Boatwright
If the duct is sealed to the exhaust fan outlet, I can't imagine how dust
would enter the system from the attic. You could, of course, seal all
perceptible joints, corners, screw holes, etc., on the housing with duct
tape.
We had a similar installation in a previous house with similar insulation.
Nothing additional was required and we had no problem.
Alfred K.
>
>>> On Thu 01 Oct 2009 09:36:50p, Alfred K. told us...
>>>
>>>> An exhaust fan has been added to the upper floor bathroom. The attic's
>>>> insulation (cold climate!) is blown cellulose particles. Is it
>>>> customary to cover the fan's top housing with some kind of a cap to
>>>> protect it from being contaminated with the insulation dust?
>>>
>>> You should *not* be exhausting bathroom air directly into the attic.
>>> There should be a duct (preferably insulated) connected to the exhaust
>>> fan and connected to an appropriate exterior vent through the roof,
>>> eave, or sidewall of the house. This would also apply to exhaust fans
>>> anywhere in the house; e.g., utility room, kitchen, etc.
>>
>> An insulated duct, of course, is there, connected to an ridge vent on
>> the roof. I am asking about some possibility of contamination even with
>> the duct present.
>
> If the duct is sealed to the exhaust fan outlet, I can't imagine how dust
> would enter the system from the attic. You could, of course, seal all
> perceptible joints, corners, screw holes, etc., on the housing with duct
> tape.
>
> We had a similar installation in a previous house with similar insulation.
> Nothing additional was required and we had no problem.
Was it in the area with very hot summers? I am thinking of potential
overheating if the fan housing is sitting deep in the cellulose without
any air gap surrounding it.
BQ340
The motor is cooled by the airflow
Wayne Boatwright
Yes, very hot but not humid. No problems at all. A lot depends on the
quality of equipment you buy.
dv
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