# venting a shed dormer roof



## jforrester01 (Jan 13, 2008)

hey guys, i was just curious what your thoughts were on venting shed roof w 2/12 pitch on the second floor of my house. Thehouse was a 1 1/2 story and i blew out the back w/ a 16 ft wide shed dormer which ties into the ridge of existing 7/12 pitch roof. B/C of low 2/12 pitch a ridge vent was not an option and the existing eave vents are un functional b/c in order to maintain headroom in the space we did not have ceiling joists , just the 2x10 rafters with drywall attached directly to them. To complicate things the house is a craftsman cottage where all the eaves and rafter tails are exposed so a soffit vent is out of the question too. Any ideas other than the small plastic circular louver vents in the blocking between the rafter tails?


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## Tin Cup (Nov 22, 2007)

without seeing the entire picture, this sounds like a perfect application for spray foam insulation and don't vent. unless of course you have an indoor swimming pool or you breed fish for the local pet stores and have 15 aquariums inside (really, i've seen this, had to gut the entire house down to the stud walls).

find a new guy in the spray foam industry and get a "deal" in trade for him using photos for his new business.

Tin Cup


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## Grumpy (Oct 8, 2003)

I just completed one of these and I will post some pics when we get a nie sunny day and I can go take sme high quality photos. 

Use Airvent products, peak filter vent if you are saying there is a one sided ridge. If you are saying you want to vent where the lower roof meets the wall, use Air vent, flash filter vent.

Spray in place, closed cell foam insulation with zero venting seems like the way to go. Higher R value, more insulation, more living space... Seems like a win win all around. However it's not really time tested yet. We've done a few roofs on jobs that had it underneath... I'm really curious to see how these roofs look in 10 years. The manufacturers say it'll be ok. Time will tell.


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## pfloyd (Feb 28, 2008)

I am currently doing one of these myself and am contemplating options. I may use 2x8 rafters with 1x4 straps on top for cross venting. That would allow me to only need about 4 vent holes in the blocking for the whole roof. Its also a little faster to sheet on 1x4 and stronger structurally.


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## Tom M (Jan 3, 2007)

Could you imagine the repairs down the road when a poor roofing job leaks and delaminates the plywood. Then you have sprayed in foam stuck to the underside. A simple leak will create new ceiling and insulation applications. And they will happen. The closed cell foam will no doubt hide the roof leaks till there is an obvious like blow offs.


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## pfloyd (Feb 28, 2008)

tom m said:


> Could you imagine the repairs down the road when a poor roofing job leaks and delaminates the plywood. Then you have sprayed in foam stuck to the underside. A simple leak will create new ceiling and insulation applications. And they will happen. The closed cell foam will no doubt hide the roof leaks till there is an obvious like blow offs.


 These sentences make no sense. What are you trying to say?


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## Slyfox (Dec 22, 2007)

When a roof leaks it has to penetrate the underlayment, decking, insulation, drywall and bam its in your home,
the foam is going to slow this process but not eliminate it thus by the time it does show up inside the home its going to be a more severe repair your looking at.

Every roof installed is going to leak eventualy "guaranteed" and how soon you notice the leak will determine the amount of damage done.


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## pfloyd (Feb 28, 2008)

So, with regular insulation, a leak will penetrate faster and require a small repair soon.With spray insulation, penetration will be much slower and require a larger repair, later on. I would say they both sound equal to me. Maybe it should be roofed properly in the first place. Do you put on your business cards " our roofs are guaranteed to leak"?? 
Its like saying not to put too many screws in drywall because there may be a plumbing leak down the road and you may have to take the panels off to find it.


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## Tom M (Jan 3, 2007)

Roofed properly in the first place. What a concept! Wow Unless the boss is up thier personally doing it, forget it. How many pablo's, sancho's or lazy white american's care if those over driven nails take 3 years to blow off instead of 20 or those under driven nails melt through in a couple of years. It didnt leak when they left. Until the pay scale increases guys who made nothing more than a days pay when they didnt lose the hours due to weather will not care about the effort they put in. That 15 bucks and hour barely puts food on the table when your putting in the hours.
The roofing trades are so important yet good practices are terribly ignored cause no one is going on that roof to inspect it and not all leaks surface after a few rain storms.


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## JonM (Nov 1, 2007)

with on every other rafter


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## A W Smith (Oct 14, 2007)

pfloyd said:


> So, with regular insulation, a leak will penetrate faster and require a small repair soon.With spray insulation, penetration will be much slower and require a larger repair, later on. I would say they both sound equal to me. Maybe it should be roofed properly in the first place. Do you put on your business cards " our roofs are guaranteed to leak"??
> Its like saying not to put too many screws in drywall because there may be a plumbing leak down the road and you may have to take the panels off to find it.


 
Floyd. What he is saying is that the foam insulation will be adhered to the back of the plywood sheathing, If any sheathing is to be removed in the future. Even for a small repair. The insulation will come of with it. It will have to be replaced with more foam.


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## pfloyd (Feb 28, 2008)

Smith. So what? Replace it with more foam! Scrape it off the plywood! Its FOAM, stick a dang sawzall in it, its no big deal......If you build with the mindset that everything will eventually fail and you need to accommodate easy repairs you are wasting your time. Build it so it DOESNT have to be repaired. What a concept.

I do agree with roofer being way underpaid, though. Its tough and important work! 30 bucks an hour MINIMUM. I'm a carpenter and I am in awe of roofers and how insane you have to be to do that.


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## Slyfox (Dec 22, 2007)

pfloyd said:


> So, with regular insulation, a leak will penetrate faster and require a small repair soon.With spray insulation, penetration will be much slower and require a larger repair, later on. I would say they both sound equal to me. Maybe it should be roofed properly in the first place. Do you put on your business cards " our roofs are guaranteed to leak"??
> Its like saying not to put too many screws in drywall because there may be a plumbing leak down the road and you may have to take the panels off to find it.


I have never seen a roof that hasn't leaked yet, they rell you right on the package they only last 20,30,40,50, yrs.


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## Slyfox (Dec 22, 2007)

pfloyd said:


> Smith. So what? Replace it with more foam! Scrape it off the plywood! Its FOAM, stick a dang sawzall in it, its no big deal......If you build with the mindset that everything will eventually fail and you need to accommodate easy repairs you are wasting your time. Build it so it DOESNT have to be repaired. What a concept.
> 
> I do agree with roofer being way underpaid, though. Its tough and important work! 30 bucks an hour MINIMUM. I'm a carpenter and I am in awe of roofers and how insane you have to be to do that.


Your missing my point,
i'm not hoping for easier repairs i'm hoping that the repair is seen before it doe's thousands of dollars in damage.
The avaerage home owner thinks about thier roof when it leaks, blows off or that one day when they pull in the drive and realise it looks like crap because its all burnt up and curling like crazy, if you install something on the roof that prevents a leak from showing up inside the home and that leak continues on unnoticed and damages decking, rafters, facia boards etc than how good of a job have you done?
Do they not have storm damage in your area?
Do they not have faulty materials in your area, ever?
Has there never been leafes, tennis balls, frisbies etc, stuck in the gutters preventing water drainage thus cause leaks in a roof in your area?
Do the 20,30,40,50 yr shingles you install in your area last 100 yrs with out leaks and the home owners just replace them because thier tired of looking at the same ole color?


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## Tom M (Jan 3, 2007)

Slyfox said:


> Your missing my point,
> i'm not hoping for easier repairs i'm hoping that the repair is seen before it doe's thousands of dollars in damage.
> The avaerage home owner thinks about thier roof when it leaks, blows off or that one day when they pull in the drive and realise it looks like crap because its all burnt up and curling like crazy, if you install something on the roof that prevents a leak from showing up inside the home and that leak continues on unnoticed and damages decking, rafters, facia boards etc than how good of a job have you done?
> Do they not have storm damage in your area?
> ...


:thumbsup: Perfect explanation Slyfox exactly my point. The whole foam thing is great concept for many reasons but things are meant to be replacable since damage is eventually going to happen one way or another.


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## A W Smith (Oct 14, 2007)

pfloyd said:


> Smith. So what? Replace it with more foam! Scrape it off the plywood! Its FOAM, stick a dang sawzall in it, its no big deal......If you build with the mindset that everything will eventually fail and you need to accommodate easy repairs you are wasting your time. Build it so it DOESNT have to be repaired. What a concept.
> 
> I do agree with roofer being way underpaid, though. Its tough and important work! 30 bucks an hour MINIMUM. I'm a carpenter and I am in awe of roofers and how insane you have to be to do that.


 so your saying a roofer will remove the plywood with 5 inches of foam sticking to it. and stop what he is doing to replace that insulation? ever consider risk? The roofers main objective is to dry in the occupied home as quickly as possible. I sure as hell wont stop my roofing project to shop around for a foam insulation contractor while my men are standing by waiting to close it in. 

Floyd I am curious. Are you really a contractor? Your posts seem like that of a curious hobbyist homeowner. You cannot seem to grasp the concept of project management nor industry practicality. Does your business have a web presence? Or even a business phone line?


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## pfloyd (Feb 28, 2008)

Why would a ROOFER be removing plywood?? Isnt that a CARPENTERS job? Thats part of the framing.Are you really a contractor? If so, you should know that.If your a good contractor, you should also try building properly instead of worrying about how to take things apart later because they failed integrity.


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## A W Smith (Oct 14, 2007)

pfloyd said:


> Why would a ROOFER be removing plywood?? Isnt that a CARPENTERS job?


Ummmm No, Roofers inspect and replace damaged sheathing as they encounter it. You really should know this.


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## pfloyd (Feb 28, 2008)

A W Smith said:


> so your saying a roofer will remove the plywood with 5 inches of foam sticking to it. and stop what he is doing to replace that insulation? ever consider risk? The roofers main objective is to dry in the occupied home as quickly as possible. I sure as hell wont stop my roofing project to shop around for a foam insulation contractor while my men are standing by waiting to close it in.


 Wow, thats a quality outfit you run. Cant let your boys get wet spending an extra half hour doing it PROPERLY. Ever heard of a tarp? Throw one up and go get some insulation. If you were smart businessman you wouldnt be admitting this cutting of corners on line.Sheesh.... Risk? Considering a roofer makes a living 40 feet in the air often without a harness, I would think putting in a piece of insulation would seem pretty safe in comparison.


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## pfloyd (Feb 28, 2008)

A W Smith said:


> Ummmm No, Roofers inspect and replace damaged sheathing as they encounter it. You really should know this.


 Ummm, OK.What if the rafters rotted too? Gonna replace that? 

One minute you say you wont wait for a insulator,or just replace a bit of it yourself in five minutes, yet you do carpentry.


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## A W Smith (Oct 14, 2007)

*What are you? 22?*

<----- see how long I have been in business squirt? Its not cutting corners, its letting the homeowner know that theres more damage than originally revealed, if theres interior damage i move to the inside only after the roof structure including rafters, soffits, sheathing and the roof itself is replaced and or repaired. And thats only if their budget allows. What if they elect to wait for more funds for the interior repair?


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## pfloyd (Feb 28, 2008)

*What are you, 93??*

I hear Alzheimer's is a *****....and yet again, you didn't answer the questions.You also contradict yourself from one post to another.End game.


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## A W Smith (Oct 14, 2007)

pfloyd said:


> I hear Alzheimer's is a *****....and yet again, you didn't answer the questions.You also contradict yourself from one post to another.End game.


 
Yes i did answer your questions. On every thread. But you neglected to answer mine. Do you remember those questions? think back. Do you have a business phone line? do you have a web presence? I will add two more questions. Are you registered with your local government as a contractor? Are you insured?


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## pfloyd (Feb 28, 2008)

And how is that any of your business? Get off your pedestal, jackass.


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## A W Smith (Oct 14, 2007)

pfloyd said:


> And how is that any of your business? Get off your pedestal, jackass.


 
Ill take that as a no


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## pfloyd (Feb 28, 2008)

I am 100 percent legal ,insured, and abide by all laws required as a sole proprietorship where i live. You wanna tell me where you live and your kids too? How about last years income tax statement? Care to divulge on THE INTERNET? You are crossing the line, Grandpa.I though age gave you wisdom:no::no:


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## Double-A (Jul 3, 2006)

Closed. This type of disrespect is unprofessional and violates our posting rules.

Folks that violate our posting rules will get bounced. End of story.


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