Bathroom Exhaust Fan Out The Roof? - Roofing/Siding - DIY Home Improvement | DIYChatroom

Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Roofing/Siding


Thread Tools Display Modes
Old 04-29-2011, 08:41 PM   #1
Join Date: Sep 2007
Location: Kansas City
Posts: 480
Rewards Points: 682

Bathroom Exhaust Fan Out the Roof?

I have previously posted a question here about whether or not to have my bathroom exhaust fans vented out of the roof? I received a resounding yes? In regards to that question, I have two exhaust fans in my home. In orer to minimize the number of holes in my roof, can I have one hole in the roof and install a coupler that that allows you to hook two hoses to it? I'm assuming that there is something like this? Is this a good idea to do this?


kennykenny is offline   Reply With Quote
Old 04-29-2011, 08:50 PM   #2
Stay-at-home GC
Join Date: Mar 2009
Location: Pittsburgh,PA
Posts: 638
Rewards Points: 500

Yes, use the appropriate 'Y' for whatever vent material you are using.


Can correctly identify Shinola 3 out of 5 times*
*Under ideal conditions

Some days, my Life needs a Rewind/Erase Button.
CplDevilDog is offline   Reply With Quote
Old 04-29-2011, 09:27 PM   #3
Roofmaster417's Avatar
Join Date: Jun 2010
Location: Springfield and Joplin Missouri
Posts: 981
Rewards Points: 500

I have never had an intersection with 2 vents,,,,All the vents I have installed have an individual duct system for each.

One question would come to mine is,,,How close are the vents to be intersected?

What are the effects of having both vents running at the same time? It does seem possible,I have never done that though.

Last edited by Roofmaster417; 04-30-2011 at 08:56 PM.
Roofmaster417 is offline   Reply With Quote
Old 04-30-2011, 06:41 AM   #4
Residential Roofer
Slyfox's Avatar
Join Date: Jun 2008
Location: Struthers, Ohio
Posts: 803
Rewards Points: 500

My question would be the same as roofmaster, why have I installed thousands of roofs, new construction and renovations and never seen it before, or at least never noticed it before.

I would think you'd be better off asking that question in a heating & cooling section of the forum "HVAC".
God Family Country Work Play
Facebook <> Twitter
Slyfox Exteriors Co.
Slyfox is offline   Reply With Quote
Old 04-30-2011, 10:08 AM   #5
Join Date: Apr 2011
Posts: 3
Rewards Points: 10

In my view it depends on the size of the individual vents relative to the combined vent. If you are using two individual 4" ducts with 4"-to-6" transitions into a 6" 'Y' vented to the roof, that is not a problem. I've done that. Basically you want to be sure the roof vent area (calculated as the diameter times the diameter divided by 1.27) is close to the sum of the areas of all incoming ducts and you'll be OK. On the other hand, sometimes it's much easier to have individual vents so as to minimize the dunt lengths. This is particularly important for typical bathroom 4" ducting.
Earl0101 is offline   Reply With Quote
Old 04-30-2011, 11:06 AM   #6
Shut in w/o Home
seeyou's Avatar
Join Date: Dec 2008
Location: Lexington, KY
Posts: 697
Rewards Points: 502

I've got a similar situation in my home. Bathrooms are back to back. I used one 8" roof vent and connected both 4" fart fan ducts to it. Two separate ducts, but only one penetration.
seeyou is offline   Reply With Quote
Old 04-30-2011, 08:50 PM   #7
Roofmaster417's Avatar
Join Date: Jun 2010
Location: Springfield and Joplin Missouri
Posts: 981
Rewards Points: 500

Ironically enough I installed 2 exhaust vents today on a job.I installed them by themselves with each having its own slinky pipe and they were about 10' apart.

I will sleep like a baby tonight knowing they are nice and water tight and will be that way for the natural life of the shingles.


Roofmaster417 is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Can I use one roof vent for 2 bathroom exhausts fans? P550 General DIY Discussions 19 05-18-2014 09:41 PM
Strange Winter Roof Leak Dragon Roofing/Siding 16 10-09-2009 06:06 PM
Basement bathroom exhaust fan install krusty HVAC 5 09-15-2009 07:41 PM
Bathroom exhaust fans PirateKatz HVAC 7 11-18-2008 03:09 PM
Exhaust for bathroom and kitchen - up or out? pcampbell HVAC 1 04-10-2008 06:09 AM

Top of Page | View New Posts


Search Engine Friendly URLs by vBSEO 3.6.1