[Greenbuilding] Ridge Vent on Corugated Metal Roof

[Frank Tettemer]

Hi Eli,

Here's my favoriteridge vent system. Used it for fifteen years now, when 
appropriate to the build.
Maximum venting area, with three inches left open, between the topedges 
of steel roofing, at the top ofboth roofs.
These come in a box, in ten foot lengths. Steel construction, very 
sturdy, with the attic ventilation exhaust vent installed with innner 
mosquito/fly/wasp screens.
Combined with soffit venting, the attic space stays cool.

http://www.vicwest.com/sites/default/files/Vicwest_E_Roofing_Book_1.pdf
Page 7 of this installation manual has the venting drawings.

Frank Tettemer
Living Sol ~ Building and Design
www.livingsol.com
613 756 3884



On 12/05/2014 8:02 AM, conservationarchitect at rockbridge.net wrote:
> Hi List
>
> Fishing again for great ideas from our list.  I have a gable end roof 
> framed with truss's at 4'oc with 2x4 purlins at 1'oc.  I am planning 
> on installing Fabral Grandrib 3 corrugated prefinished metal roofing.  
> It is a simple roof with no hips or valleys.  The top chord overhangs 
> the wall and are left exposed with a 2x fascia installed to keep them 
> from twisting at the end. The truss has a vertical raised heel at the 
> end sufficient for additional cellulose over the 8" eps foam that runs 
> below the bottom chord. I am also installing a continuous soffit vent 
> installed vertically just below the top chord and above the cellulose.
>
> My plan is to install a ridge vent.  I like the grand rib, because the 
> profile of the ribs offers significant free space so that boient 
> driven air flow has a vertical path to follow to the ridge.  One 
> contractor describe his ridge vent using a ridge cap over foam rubber 
> compressible material that can work around the shape of the ridges.  
> My concern is that this foam rubber may reduce the free space I would 
> like for encouraging the air-vapor flow.
>
> I have thoughts of adding blocking and a screen to lift up the ridge 
> cap (standard or fabricated) to greatly increase the free space.  The 
> roof pitch is 9/12.  Therefore, I would expect a decent amount of 
> overlap (4"-6"?)over the top edge of the corrugated roof will protect  
> the roof from wind driven rain driven water.  I could also get my 
> installer to turn the top edge up to block flow going up hill.
>
> I hope people on our list are willing to share your ideas for ridge 
> vents over corrugated metal roofs.  I am sure they are out there.
>
> Thanks in advance.
>
> Eli
>
>
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org 
>
>

--