Roof vent? bathroom exhaust fan vent?

I had a roof and sheathing installed on my home this last Summer. The contractor installing the sheathing cut a hole in the roof and nailed a piece of flexible duct to the plywood edge to hold it just at the plywood line. The roofing contractor ( someone different) was told it would be a bathroom vent at that location. At one point I bought a kit with the roof vent, but I was told those were junk and the one installed was better. Now, I am installing my bathroom vent fan and I see a piece of duct flush with the plywood top and a dome like thing with a cap. I must be missing something. It seems to me the moist air leave the bathroom will collect in this done and cap and/or rot out the plywood. I expected the duct to slip over something and go out to the outside world. What is the proper way for this vent to be and is there any way I can make this work? Any help would be appreciated.
J :frowning:

can you post pics of inside and outside?

I agree sometimes i have noticed size changes but thats what adapters are for. Will need pics to help thou

You should have something similar to one of these, IMO the black one with the flapper inside is the better choice.

I hope the following pictures help and/or actually come up. The stack to the right on the roof top picture and the view from inside the attic is the other picture’s. It seems like the 4" duct needs something inside to tie to.
Thanks, for any input.


It does not look like the one in your pictures. The pictures sent show the roof top view then the following pictures are looking up from the attic. I was thinking if I wedged up a large enough diameter pvc pipe up into it then reduced it down to 4" in the attic that might work. Is there any hope? Any ideas? I just had the roof replaced so we do not want to redo any of that work. Could the top or cap be removed and a custom one built to resemble a correct vent. Any help would be appreciated.

Looks like a factory. I use the low profile flapper style similar to what demon posted. They come in steel which I like better than the black plastic one.
Where are you located? The flexible duct is typically insulated to help control condensation. Warm aluminum in a cold attic tends to condensate.

The pictures seem to have worked. I will insulate what ever is used I am just not sure that nailing the duct to the plywood is the right way to install it. Should there be something up in (Picture looking up) that the duct will hook up to. It seems like the bathroom stream will not escape to the outside correctly. Is this the right type of vent for the application? can it be made to work? Any ideas appreciated.

The picture is not a factory it’s just a close up picture of the vent flashing. the other picture is the view looking up it from the atic. I think the diameter is 4 or 5 inches. Should a piece go up into it and then the vent cap at that point?

[quote=“Jwhitman”]Should a piece go up into it and then the vent cap at that point?

It looks to be about 10 inches high, if your exhaust stops at the plywood, I could see moisture building up in there and rotting the plywood under the flashing.


As My Pic’s aren’t Loading ?

[quote=“HelperWon”]HOW DID YOU POST THOSE PIC’S ?

As My Pic’s aren’t Loading ?[/quote]

Did you click on the IMG box? It doesn’t work for the first post, only on replys.

To load an image I did the following.
Pressed the IMG tab
Then after BBcode image helper appears
Select Browes.
Find your picture in you files
Select the picture
Select upload
Image should appear in the preview screen.
Now, select the insert button to put it into the message.
Hope this helps.

On the message page at the bottom near the submit button you must uncheck the Disable BBcode on this post.

So, back to the problem with the vent. How is this type of vent suppose to work? Do I need to install a pipe made of pvc,metal? What should be there. I really do not understand venting. The other vents around the roof were covering vent pipe and not exhausting bathroom moisture. Can this set up be made to work? I would really appreciate any advice.