Running Vents Under Metal Roofing. - Roofing/Siding - DIY Home Improvement | DIYChatroom


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

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 04-17-2014, 04:14 PM   #1
Newbie
 
Join Date: Mar 2014
Posts: 12
Rewards Points: 10
Default

Running vents under metal roofing.


So we are going with the standing seam, hidden fastener metal roofing on our manufactured home. We are leaving the existing 3 tab on the roof and overlaying with furring strips of 2x4 or 1x4 depending on this question:

It is my goal to have no roof penetrations. To accomplish this I need to deal with three 1 1/4" plumbing stack vents and two bath fan vents.

One thought is to use 2x4 furring and run the stack vents along the roof in the space created by the 2x4 and exit into the ridge vent. Obviously if I use a 1x4 or no furring strip, this wouldn't work.

Question is how to deal with the bath fan? I could maybe have some kind of low profile sheet metal duct built to lay in the cavity and exhaust into ridge vent. Seems like that could lead to moisture-laden exhaust running under the metal panels. Am I worry about this too much considering there would be an 1 1/2" airspace and asphalt in the void?

Other option might be to try to pull the duct through the very limited "attic" cavity and exhaust it out the soffit.

Thoughts?

Advertisement

Johnny Oregon is offline   Reply With Quote
Old 04-17-2014, 04:43 PM   #2
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 27,805
Rewards Points: 726
Default

Running vents under metal roofing.


Not a great plan, stick with the proper roof jacks made for metal roofing.
Your sewer vents work by the air passing over them creating a negative pressure to suck out the gasses.
For a bathroom vent to work it needs a full 3 or 4" port, restrict the flow and it's useless.
Have you priced out what the roof is going to cost?

Advertisement

__________________
When posting in forums, letting us know your location will help others give better feedback/advice/solutions to your questions
joecaption is online now   Reply With Quote
The Following User Says Thank You to joecaption For This Useful Post:
Windows on Wash (04-17-2014)
Old 04-17-2014, 05:08 PM   #3
Newbie
 
Join Date: Mar 2014
Posts: 12
Rewards Points: 10
Default

Running vents under metal roofing.


Quote:
Originally Posted by joecaption View Post
Not a great plan, stick with the proper roof jacks made for metal roofing.
Your sewer vents work by the air passing over them creating a negative pressure to suck out the gasses.
For a bathroom vent to work it needs a full 3 or 4" port, restrict the flow and it's useless.
Have you priced out what the roof is going to cost?
Thanks for the input. I hear what you are saying on the vents and air flow. Odd thing is, since I've looked into metal roof I've seen three or four manufactured homes in our area with no roof vent penetrations at all.

I hadn't planned on restricting the size of the bath vent...just reconfiguring the shape. Going with more link an oblong or rectangular vent with same surface area.
Johnny Oregon is offline   Reply With Quote
Old 04-17-2014, 05:09 PM   #4
Member
 
Join Date: Jan 2014
Location: Central Illinois
Posts: 1,018
Rewards Points: 888
Default

Running vents under metal roofing.


In addition to what Joe said.If furring your metal roof on top of your shingles,the closure designed for you metal roof will not work.
mako1 is offline   Reply With Quote
The Following User Says Thank You to mako1 For This Useful Post:
Windows on Wash (04-17-2014)
Old 04-17-2014, 05:32 PM   #5
Newbie
 
Join Date: Mar 2014
Posts: 12
Rewards Points: 10
Default

Running vents under metal roofing.


Quote:
Originally Posted by mako1 View Post
In addition to what Joe said.If furring your metal roof on top of your shingles,the closure designed for you metal roof will not work.
What do you mean by "closure"? Nothing would change on the ridge vent? Flashing may have to have a longer to leg to make up for the added height of the furring.
Johnny Oregon is offline   Reply With Quote
Old 04-17-2014, 06:11 PM   #6
Member
 
Join Date: Jan 2014
Location: Central Illinois
Posts: 1,018
Rewards Points: 888
Default

Running vents under metal roofing.


There is a foam closure that goes between your siding and roof deck at the eaves.
mako1 is offline   Reply With Quote
Old 04-17-2014, 06:34 PM   #7
Newbie
 
Join Date: Mar 2014
Posts: 12
Rewards Points: 10
Default

Running vents under metal roofing.


Quote:
Originally Posted by mako1 View Post
There is a foam closure that goes between your siding and roof deck at the eaves.
I guess I'm not following. The siding and roof deck already exist on the home. The instructions for this metal roofing list no foam closures. It goes roof deck (or furring strip)...fascia and eave trim...roofing panels....edge cap and ridge vent.

Are you talking like the foam wiggle board used on corrugated roofing? I'm talking standing rib roof here.
Johnny Oregon is offline   Reply With Quote
Old 04-17-2014, 06:56 PM   #8
Doing This Way Too Long
 
Join Date: Jun 2008
Location: North Idaho
Posts: 1,160
Rewards Points: 524
Default

Running vents under metal roofing.


Not sure why you are concerned about the penetrations in the roof. The ones you are describing simply need a dektite to seal it up. Sounds like a lot of work for little benefit and possibly causing unforeseen problems.

What mfr and system?
__________________
Roofing 101 - Think Like Water
OldNBroken is offline   Reply With Quote
Old 04-17-2014, 07:04 PM   #9
Member
 
Join Date: Jan 2014
Location: Central Illinois
Posts: 1,018
Rewards Points: 888
Default

Running vents under metal roofing.


I mistyped.The foam closures go between the roofing and the deck.I understand your talking about standing rib .The type I have installed still had foam closures.
mako1 is offline   Reply With Quote
Old 04-17-2014, 07:06 PM   #10
Newbie
 
Join Date: Mar 2014
Posts: 12
Rewards Points: 10
Default

Running vents under metal roofing.


Quote:
Originally Posted by OldNBroken View Post
Not sure why you are concerned about the penetrations in the roof. The ones you are describing simply need a dektite to seal it up. Sounds like a lot of work for little benefit and possibly causing unforeseen problems.

What mfr and system?
Obviously I'm concerned about leaks at penetrations! 20 years in the RV industry taught me if there is a hole in a roof, it's a good chance it will leak eventually!

I agree maybe I'm making too much of it but since I've seen a couple homes in the area with no pentrations, I know it can be done!

Taylor and AEP are the two systems I'm looking at.
Johnny Oregon is offline   Reply With Quote
Old 04-17-2014, 07:56 PM   #11
Doing This Way Too Long
 
Join Date: Jun 2008
Location: North Idaho
Posts: 1,160
Rewards Points: 524
Default

Running vents under metal roofing.


If you are on the rusty side of the state, might try Bryer or CustomBilt. They both have a 1750 panel and are in that area.

Best way to do those boots is embed them in a good butyl with a screw every 1 to 1 1/4" around perimeter and hose clamp at the top. Will last the life of the roof if done properly. We do them on flat metal roofs all the time with no problems
__________________
Roofing 101 - Think Like Water

Last edited by OldNBroken; 04-17-2014 at 07:59 PM.
OldNBroken is offline   Reply With Quote
Old 04-17-2014, 07:57 PM   #12
Doing This Way Too Long
 
Join Date: Jun 2008
Location: North Idaho
Posts: 1,160
Rewards Points: 524
Default

Running vents under metal roofing.


Hold on, RV industry? Ima guess Hermiston area then.

Do I win?
__________________
Roofing 101 - Think Like Water
OldNBroken is offline   Reply With Quote
Old 04-17-2014, 08:02 PM   #13
Newbie
 
Join Date: Mar 2014
Posts: 12
Rewards Points: 10
Default

Running vents under metal roofing.


Not quite...Eugene area!
Johnny Oregon is offline   Reply With Quote
Old 04-17-2014, 08:19 PM   #14
Doing This Way Too Long
 
Join Date: Jun 2008
Location: North Idaho
Posts: 1,160
Rewards Points: 524
Default

Running vents under metal roofing.


Damn, I was way off
__________________
Roofing 101 - Think Like Water
OldNBroken is offline   Reply With Quote
Old 04-18-2014, 01:25 PM   #15
Low Slope Roofing
 
Join Date: Jan 2011
Location: Nebraska
Posts: 789
Rewards Points: 1,056
Default

Running vents under metal roofing.


The RV industry also just plunks a hole in the roof adds the vent and goops it down. IF done the proper way like OldNbroken said the deck tite boots last a very long time. The only thing we do that may be over kill is put water stop on the boot around the pipe then clamp it.

Venting moisture inside of a space is a bad idea. That moisture will run down the underside of the panels and cause issues.

If furring the deck you will need a longer drip edge and possibly rake trim. Also I've never installed a standing seam panel with a foam closure except on the hips and ridges. even then you can do it with out needing them.

Advertisement

1985gt is offline   Reply With Quote
Reply


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
How to Insulate Metal Roofing from the Interior PappyO Insulation 4 02-09-2014 10:54 PM
Manufacture History Roofmaster417 Roofing/Siding 6 02-23-2012 03:40 AM
Roofing Material History Roofmaster417 Roofing/Siding 4 09-08-2011 05:49 PM
Metal Roofing NE dealfiles Roofing/Siding 0 07-05-2010 07:44 PM
metal roofing??? mopowers Roofing/Siding 4 05-29-2010 05:52 PM




Top of Page | View New Posts