# How would you vent this?



## Roofsafe (Oct 29, 2008)

This roof has ridge beam, 2X12 rafters, no soffet, and R-38 bat insulation. Its a 7/12, the valleys are also beams, the rafters are nailed into beams top and bottom.


----------



## Grumpy (Oct 29, 2008)

Who designed this mess? 

I wish you had a better shot of the overhang at the gutter line. Are you saying that the wall goes all the way up to the bottom of the sheathing at the gutter lines? 

Are the ceilings going to be cathedral along the bottom of the rafters?


----------



## Roofsafe (Oct 29, 2008)

Yes Grumpy, the cieling is the bottom of the rafters.


----------



## The Roofing God (Oct 31, 2008)

Are you saying that the wall goes all the way up to the bottom of the sheathing at the gutter lines? -Grumpy

he means "you`re saying the rafter spaces are blocked Vern?


----------



## Grumpy (Oct 29, 2008)

Is he going to insulate with spray poly foam between the rafers? If so you may not need to ventilate. I do believe some shingle manufacturers allow for no insulation, but I don't know for sure because it's all here-say. What shingles are you planning to install?


----------



## Roofsafe (Oct 29, 2008)

Yes, the spaces between the rafters are closed on both ends.


----------



## The Roofing God (Oct 31, 2008)

certainteed supposedly allows it,according to other threads anyway


----------



## apehangeralfy (Nov 10, 2008)

If he is planning on foaming it I have I would peel-n-stick the whole thing and shingle with the approved shingles (Elk was the ones I used so check with your GAF rep)


----------



## Roofsafe (Oct 29, 2008)

This is how I vented this roof, what you are seeing is what I call strip vents, these are actually intake vents, they exhaust at the ridge. I've been doing these for almost ten years now and haven't had any problems with them. I have gotten letters from the HO's telling me how thier utility bills have gone down but thats what I told them would happen with positive air flow in thier attics. 
I take the filters out of the vents I use so there isn't any thing to plug the vents at either end, I have a picture to post later that I took of this roof to show what I have talked on other forums about filters becoming a problem. 
Since I am an out of the box roofer I am always interested in comments made about what I do and show on these forums, learning from each other is what makes these forums habit forming.

http://www.roofingtalk.com/picture.php?albumid=2&pictureid=83


----------



## tomstruble (Jan 19, 2009)

you dont have any prolem with water being sucked in the vents with the filter out?


----------



## Roofsafe (Oct 29, 2008)

The reality of a filter is that it can also act as a wick, no filter, no wick.


----------



## tomstruble (Jan 19, 2009)

i would probably recommend installing Hunter Cool Vent and venting the roof thru that


----------



## Roofsafe (Oct 29, 2008)

The filter can act as a wick, It might keep particulate matter out but where does it go? Also, filters are made to collect matter, right? keeps debris out by stopping it from entering, that means it has to collect, how often do you change filters in roof vents? 
I have a picture I'll post when I get back later today to show you what I mean.


----------



## tomstruble (Jan 19, 2009)

not arguing just askin


----------



## Roofsafe (Oct 29, 2008)

http://www.roofingtalk.com/members/roofsafe-62/albums/how-would-you-vent/86-100-2527.jpg
Sorry Tom, I wasn't trying to argue, didn't realise there was a second page and thought I had lost my post.
The pic above is of a S V II filter, a lot of what was on the filter was knocked off when I took it off the roof, it had been on the roof for six years, was 85 feet from the nearest tree, had grass all around and was about 90 feet from a paved road. There was equal intake for the roof on both sides in the eaves, what is on the filter is what had blown in with the wind, less what was knocked off while taking it off the roof.


----------



## Ed the Roofer (Sep 15, 2008)

Vern,

In you User Control Panel on this and other V-Bulletin Forums, you can set how many posts show up per page when viewing.

I have mine set up for 50, which is the maximum.

It makes finding all the posts a lot easier.

Ed


----------



## tomstruble (Jan 19, 2009)

i see what you mean:thumbup:


----------



## Roofsafe (Oct 29, 2008)

Thanks Ed, I found it.


----------



## Roofsafe (Oct 29, 2008)

http://www.roofingtalk.com/members/roofsafe-62/albums/how-would-you-vent/88-100-2131.jpg
This is a picture of either trimline or cora vent , I don't know which one, but it shows that it plugs up. This was a call to nail the cap back in place because the H Os were going to close in three days and it had to be done.
The Idea that the plastic doesn't create static when the warm moist air passes through it and loads up with dust is a myth. As you can see here it not only loads up, it plugs up, here, the dust we have is adobe clay, add a little more moisture in the form of rain and you get brick.
When I put my hand over the vent when I got up on the roof there was no air flow, just radiant heat, when I nailed the shingles back my last hit to bring the nail flush with the shingle there was a poof of dust out of the vent, when all shingles were on I put my hand back and there was air flow at the point where the new nails were.
Shouldn't take long to figure why I'm picky about what I put on my customers roofs.


----------



## rooferguy (Mar 4, 2011)

if you have a vaulted celings you will need to use insulation baffels the kind they use above sofits so they can breath these need to be installed from eave to peak between the rafters before you use sprayfoam this will allow the roof to breath you will need continuse ridge vent at the top


----------

