# Best way to install bathroom fan vent through exterior wall??



## tigerbalm2424 (Feb 28, 2007)

Im working on finishing my basement and I need to vent the bathroom fan through an exterior 2X6 wall that has vinyl siding out the outside. Obviously I could hack it up with a sawzall but I am looking for some hints or tip on the correct/best way to cut the hole in the siding and seal the vent up correctly. Keep in mind I live in MN and its cost out so the siding is probably brittle.

I picked the typical vent such as below, in the 3 inch variety.


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## Bondo (Dec 8, 2007)

Ayuh,.......

When I did 1 like that, thru Vinyl siding,.....
I used a holesaw,+ ran it Backwards to make the cut.......
'course is Slower that way, but less likely to Hang,+ Rip the siding......


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## tigerbalm2424 (Feb 28, 2007)

Bondo said:


> Ayuh,.......
> 
> When I did 1 like that, thru Vinyl siding,.....
> I used a holesaw,+ ran it Backwards to make the cut.......
> 'course is Slower that way, but less likely to Hang,+ Rip the siding......


Sounds good. Then did you just install the vent and caulk around its lip directly to the siding? Did you have to peel off any pieces of siding to get it through the hole or did you make the hole larger than the square section? Didn't know they make 4" hole saws!


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## njchan (Jan 4, 2008)

tigerbalm2424 said:


> Sounds good. Then did you just install the vent and caulk around its lip directly to the siding? Did you have to peel off any pieces of siding to get it through the hole or did you make the hole larger than the square section? Didn't know they make 4" hole saws!



they do, they're just really $$$ ... was at home depot and I think they were going for $60+


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## tigerbalm2424 (Feb 28, 2007)

njchan said:


> they do, they're just really $$$ ... was at home depot and I think they were going for $60+


Yeah, I just left HD and they arent worth the money for one job. Looks like its sawzall for the sheething and dremel for the siding!!!!:laughing:


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## Ron6519 (Mar 28, 2007)

One issue with the siding is that the housing of the vent will not sit flat on the siding. The siding, depending on exposure will be 2",4",5", etc. Try installing a composite block where the vent will go so it will sit flat against the house. You can wrap it in "J" channel and caulk it if necessary to seal it against the weather. Sliding ice and water shield under it would be even better.
You also hide the sawzall cut hole from the outside.
Ron


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## tigerbalm2424 (Feb 28, 2007)

Ron6519 said:


> One issue with the siding is that the housing of the vent will not sit flat on the siding. The siding, depending on exposure will be 2",4",5", etc. Try installing a composite block where the vent will go so it will sit flat against the house. You can wrap it in "J" channel and caulk it if necessary to seal it against the weather. Sliding ice and water shield under it would be even better.
> You also hide the sawzall cut hole from the outside.
> Ron


If you wouldnt mind, can you elaborate a little more? 

1. Can you post a picture of what a composite block looks like and how I would use it? (where it would go). Im having trouble picturing this. How does it coinside with with vent? Where does the ice and water fit in?

Thanks again!


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## Ron6519 (Mar 28, 2007)

They sell wood/plastic boards that are used for fascia. They are 1x6 or 1x8. You fabricate a square piece of this and use it as a template. You cut out a square piece of siding, cut the hole for the vent and install the ice and water shield against the sheathing and install the flat composite board over the ice and water shield. Now you have a flat surface to install the vent against.
If you go outside with the vent, you will see that it will probably not sit flat against the house due to the siding profile.
What profile is the siding?
Ron


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## tigerbalm2424 (Feb 28, 2007)

Ron6519 said:


> They sell wood/plastic boards that are used for fascia. They are 1x6 or 1x8. You fabricate a square piece of this and use it as a template. You cut out a square piece of siding, cut the hole for the vent and install the ice and water shield against the sheathing and install the flat composite board over the ice and water shield. Now you have a flat surface to install the vent against.
> If you go outside with the vent, you will see that it will probably not sit flat against the house due to the siding profile.
> What profile is the siding?
> Ron


Ahhhhhhhhhhh. I get it now. Thanks! You are correct, the profile of the siding is not straight.


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