Low/Steep Slope Ventilation


#1

Half of my 40’ wide house has has a dormer. The front roof of that section is a 10/12 pitch, the back is a 1.75/12 pitch. I have no eaves to install vented soffits. I am reroofing and would like some options on the following:

The low slope portion will be a 2 or 3 layer mod-bit system, the rest will be shingles.

I want to install a ridge vent along the entire 40 length of the house. But I will not cut the slot on the back of the dormer section to prevent weather infiltration. Gable vents are located at both ends of the house. Will this work?

Also, can anyone direct me to a detail that shows how the transition is made from shingles to a low slop roof product. Would the mod-bit sheeting be installed under or over the ridge vent.

Thank you


#2

Hi,

You have vents coming in the gable ends. Chances are the insulation is back in the rafters and ridge vent will do no good.


#3

The insulation is located in the ceiling joists which are below the gable vents.


#4

If you are installing ridge vent then there will be no transition from shingle to modbit except at the ends, 24" either side, and here just run the modbit down some, and shingle over it then add some cap.
Ridge vent should work just fine with the vents at the gable end.


#5

Thanks. You say 24" from each end. I guess that means that the ridge vent stops before the ends of the roof?

Also wondering if anyone had any experience with the self adhering modified systems. Certainteed, GAF and Tamko all look to have basically the same product. Is any one better than the others?


#6

I like the Certainteed and Mule Hide brands for the SA roofs.


#7

Hi,

The insulation will be packed on the sloped side below the ceiling joists.

The gable vents are the best vents for your house.

No matter what the TV told you.


#8

[quote]

You mean you are not absolutely thrilled with
the “leaky vent”, The structure destoying vent,
ie… “the ridge vent”

Apparently, some Shingle roofing manufactuers
(not sure whom) are telling homeowners and roofers to close up the gable vents and install the leaky, structure destroying vent.

Oh yeah, and your shingles are going to last 40 and 50 years. guaranteed they say. Guaranteeeeed.
Sometimes you have to pay them extra for the lie.
Sometimes it’s free.


#9

[quote=“roof-lover”]

[quote]

You mean you are not absolutely thrilled with
the “leaky vent”, The structure destoying vent,
ie… “the ridge vent”

Apparently, some Shingle roofing manufactuers
(not sure whom) are telling homeowners and roofers to close up the gable vents and install the leaky, structure destroying vent.

Oh yeah, and your shingles are going to last 40 and 50 years. guaranteed they say. Guaranteeeeed.
Sometimes you have to pay them extra for the lie.
Sometimes it’s free.[/quote]

Can you elaborate on that statement a little, I don’t quite understand what you are saying…


#10

I said that the ridge vents are leaky
and they take away from the structural integrity of your home.


#11

never had any problems with the ridge vent snow country is all i use


#12

[quote=“roof-lover”]I said that the ridge vents are leaky
and they take away from the structural integrity of your home.[/quote]

Well that still doesn’t explain anything…

I, personally have been using shinglevent II, ridgemaster plus, and snow country for many years, haven’t had a problem with any of them yet.
If there is some reason that using these products may result in my customers home deteriorating or possibly collapsing I feel I need to know about it.

Omni ridge, well, yea that lets snow in…

What do you know about snow, ice, ice dams, interior humidity, mold growth, etc…

I would like to learn something from you, would you be so kind as to share your knowledge?


#13

Just yesterday, I had the opportunity to explain how I have handled similar situations in the past.

Please skip the parts of this copy/paste e-mail reply, but pay attention to the portion referring to the 12/12 front tie in to the low slope rear roof section and how I have trained my guys to install the Shingle Vent II and adapt it to work in the exact same type of scenario.

Ed

Copy/Paste:
**I have used the Shingle Vent II Ridge vent on 2 1/2 per 12 pitch roofs, but I am not confident that someone else would take the appropriate due caution and additional measures to ensure it’s water-tight integrity.

If that option appeals to you, then this is what I do in those scenarios, if you have ever seen a cape cod 12/12 front of the house with 2/12 near flat roof dormer in the rear.

I install an additional baffle "Inside of where the center of the Ridge Vent product gets positioned. It really is just a piece of Aluminum J-Channel, with the longer extension being nailed to the flat roof and then that part of the J-Channel get either the flat roof membrane modified bitumen installed over it or shingles nailed up to the J feature. The J Profile faces down towards the eave. On your roof, this would be on both sides of the cut-out slot.

Then, I position the Shingle Vent II over the J-Channels, but prior to nailing it in place with 2 1/2" to 3" hand nails, I apply a very liberal amount of either Geocel or OSI NP-1 caulking sealant under where the Ridge Vent product is to make contact with the roof.

The interior J-Channel should prevent any blown in snow or rain. I have been using this technique since 1991 and have not had a call back so far, with between 15-25 such type situations.**

Otherwise, dependent upon your soffit width on the overhangs on the gable/rake edges, I would consider a powered gable vent. One on one side with the fan and one on the opposing wall, without the fan, so that one will pull the air flowage directly across, under the ridge, so one would be the intake and one would be the exhaust.

I noticed from your diagram, that you currently have small box shaped gable vents in those walls now and I wonder if the Attic Ventilation is currently being “Short-Circuited”, as the theory states as a potential affect. I doubt it in your case, even though they should have been sealed off to prevent that possibility from occurring.

I more than likely think that some poor workmanship caused the problems. When anyone removes any of the materials on your roof from either the old mushroom vent holes or the ridge vent slot covering, be on the roof and take pictures and feel if and where any of the wood is wet. If it is “Moist” continuously, it more than likely, but not assuredly, was from humidity building up the internal RH factor to a point of condensation, sufficient enough to accumulate and cause leaks. Once again, I doubt that to be the case, because I believe you stated that the leaks were during this current wave of 72 hour continuous rain we all had. We had around 10 1/2 inches in Carpentersville and Algonquin this past weekend. But, that also increases the humidity levels of the interior of improperly ventilated attics, so just one more item to be cognizant about.

If the wood is primarily wet where exactly the leak sounds came from, then it is just plain old faulty sealing of the products to the roof and inexperience, but that is how someone gets experienced, unfortunately.

Sincerely,

Ed


#14

Why do you only use snow country?

Why do you not use all the other manufacturers
ridge vents ?


#15

Why change when you find something you are satisfied with and continues to work.

Snow Country and Shingle Vent II seem to be nearly identical and I have no intention of switching from Shingle Vent II, except for the one time the Snow Country got delivered by mistake.

I don’t look for the cheapest products, but the ones that perform as stated so that I can place my word and reputation on it.

Ed


#16

[quote=“ed the roofer”]

Copy/Paste:
**I have used the Shingle Vent II Ridge vent on 2 1/2 per 12 pitch roofs, but I am not confident that someone else would take the appropriate due caution and additional measures to ensure it’s water-tight integrity.

If that option appeals to you, then this is what I do in those scenarios, if you have ever seen a cape cod 12/12 front of the house with 2/12 near flat roof dormer in the rear.

I install an additional baffle "Inside of where the center of the Ridge Vent product gets positioned. It really is just a piece of Aluminum J-Channel, with the longer extension being nailed to the flat roof and then that part of the J-Channel get either the flat roof membrane modified bitumen installed over it or shingles nailed up to the J feature. The J Profile faces down towards the eave. On your roof, this would be on both sides of the cut-out slot.

Then, I position the Shingle Vent II over the J-Channels, but prior to nailing it in place with 2 1/2" to 3" hand nails, I apply a very liberal amount of either Geocel or OSI NP-1 caulking sealant under where the Ridge Vent product is to make contact with the roof.

The interior J-Channel should prevent any blown in snow or rain. b]

**

You’re buying the best ridge vent you think you can buy and still you are doing a whole lot of work to keep it from leaking.

How come the manufacturer doesn’t mention any of these procedures.

I thought we were supposed to install to manufacturers specifications.

I remember back when they said to cut "2 inches on both sides"
I did not follow it…
I guess they all got a WHOLE bunch of leaky vents
a whole lot of feedback and a smack in the mouth
because now they say “1 inch on both sides”

The vents are still leaky, especially the rolled ones.
But i can still see my nails through the vent slots so i know the rain can see them.

When a home is designed around ridge vents, they frame in the structure for the ridge vents.
They have a peice of wood that goes between each rafter(on both sides mind you) so the plywood is not flapping in the wind. Its called blocking.
No plywood is supposed to be flapping in the wind with no support.

No roofer does this. We would never get your job done.

It is just a matter of time before goverment democrat over-regulation comes to your town with an inspector on your roof during the middle of your job and after it.

Cutting out the top of the roof without installing blocking on both sides is taking away the integrity of your roof and an inspector is coming to a town near you soon… to make you do it.

And to install the blocking correctly, i would need to take off all the plywood across the top of the roof.

Where i live, some inspectors have already started making us block-out all of our Off-ridge vents.
Its just a matter of time before they have the power to make us block out all the ridge-vents.
I already have to send several 2x4s to every single job because of this. they make up their own rules every day.

High material prices will not put you out of business if you keep your margins the same. Over-government regulation can and is putting people out of business.
Which hurts everybody.[/quote]


#17

exactlt i use shinglevent II also I just think these 2 work best and look the best quality work pays