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friedric 04-28-2012 11:07 AM

bathroom venting
I own a 2 story house with a flat roof,no crawlspace just 12" rafters.I like to install a fan however the only way to go is through the roof or into a skylight shaft 3 feet by 4 feet going from the first floor through the roof with a pyramit skylight that is vented.older type but good condition.also there is a closed window in the bathroom for light,verry nice
The venting pipe from the fan would be about 30" away from the opening.the reason i dont like to go through the roof is because the lowest point is right above the bathroom so after it rains it takes a few houres to drain off.
my naibor has the same situation.he installed a sliding window but closed up the skylight in his bathroom first floor because of smell comming down when the tenant had the window open.
i have ben searching for weeks to get the right answer.would it be ok to vent into the shaft close to the oppening or would it cuse moister proplem.i eventually have to redo my roof in 3-4 years than it could be done through the roof properly.
Thank you
excuse my english not my first language

Snoonyb 04-29-2012 09:55 AM

Vent it strait up using a pich pocket;

nealtw 04-29-2012 09:11 PM

Snoopy's suggestion is the right answer, A window that opens is not a good idea, as they are never open when you need it open and venting into the skylite would add moisture. You could use a wall vent and go straight out as a temp untill you get the roof re done, but a wall vent tends to put moisture to near soffet vents.

friedric 05-08-2012 09:52 AM

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thank you guys for your reply.i do have to agree with you.however i dont wont to take a chance trough the roof.i noticed that the lowest point of the roof is right on top of the bathroom.i think i will go streight in to the skylite shaft.remove one pannel form the skylite and replace it with a 1/4" plexiglass with a 3" hole and mount the exhaust vent-roof cap. this is a pyramite skylite with a 45 decree something like the picture with 16 panels and a venting cap that is open.this idea was given to me by a someone i met a home-depot,he was doing this at his house.what you guys think?

nealtw 05-08-2012 05:48 PM

If the skylite is in the bathroom you may want to use some sort of powered vent installed into the plastic. If it is not in the bathroom you will want to pipe it all the way.

Snoonyb 05-08-2012 09:11 PM

If the glazing in the skylite is glass and not tempered, have a glazer cut the hole and install the roof-jack.
Again, if the glass in tempered, have the glazing replaced by a glazer.
Gasketing in skylites have an undisturbed life expectancy.
So you'll have a warranty.

friedric 05-21-2012 06:47 PM

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Thank you guys again
well this ist the week.i spook to someone that builds and installs B-venting.he says that is what the do alll the time.replace the glass pannel with plexiglass.he suggested that i could do it myself,cuz he would have to charge about $500.i am pretty good in DIY.but i forgot to ask a few question,maby you guys can help me out.i am going streight into the sl-shaft,3feet by 5 feet.the lengt of the pipe will be about 5feet,than either a flex or 45decree with another 30" to the cap.what i forgot was
1.schould i use alluminium or calvenized?
2.what kind of culking on the cup to the glass.
3.insulation.i have 9" between ceiling and roof with styrofoam 1,5"on the inside on top of ceiling.i have a nice flow of air and everything is try.
how would i insulate the duct,i was thinking of getting a sleave,fibreglass.or just a sheet of fiberglass and lay it on top of the tube.???????????
one other thing that has me wondering.the fan is 8x8.5x5.5.and is attached to the rafter on one side since the space between rafters is 12" or 14" schould i build up on the other side?
well cant wait to get it up there,my new tenant is moving in soon.
Thanks again i am clad i found this side.
i u/l a pic dont know if it helps much.the duct will be right on top of the window,little to the right,

Snoonyb 05-21-2012 07:02 PM

The big box's sell duct wrap.
Use the same caulking for both applications.

friedric 05-22-2012 07:24 PM

Thanks Snoonyb,i did buy that duct wrap.
today i did the work.installed the fan, 60" of streight galv 4" tubing into the skylite shaft,taped with allu und insulated with duct wrap ,hooked it up and works great.
now all i have to do is a 45 than a straight 20" to the skylite duct.
but here is the kikker und it kills me.the tube is sloping down to the fan about an 1/2"
or i am thinking if i slope the other way would'n any condensation stay in the 45 Elbow? and since i fan out to the top and not to the side will it make a differance.

your help is really appriciated.

nealtw 05-22-2012 09:06 PM

With insulation the water should not condence before it is outside, as long as you run the fan long enough.

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