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Attic / Roof Venting Question

daen's picture

Attic / Roof Venting Question (post #185481)

daen on Mon, 03/01/2010 - 07:04
in

I am building a new workshop and have some questions about venting the attic space. The building will have soffit vents for the intake. If I install both gable end vents AND roof ridge vents, will they interfer with proper flows or just act as belt and suspenders?

The reason for this is that we are building both the workshop and a home. The workshop is getting done first. The home and the workshop will have tile roofs that match. However, we have not picked out tile yet. So for the time being the workshop has rolled roofing installed.

The ridge vent for the clay tiles isn't on the ridge, but rather replaces a few tiles close to the ridge. Without the tiles I can guarantee I'll put them in the wrong place if I do it now. So I am installing gable end vents (which go well with the achitecture) and plan to add the roof top vents when we install the tile in the next year or two.

Thanks, Daen

-A +A

my roof is unvented. To do (post #185481, reply #1 of 4)

by MrSQL in reply to daen [original] on Mon, 03/01/2010 - 13:44

my roof is unvented.

To do this for asphalt shingles simply use zero perm membrane instead of tar paper, then use a shingle that is rated for an unvented roof.

Make sure you building inspector will accept an unvented roof.  I had to provide my engineers approval for the inspector.

 

General consensus here over (post #185481, reply #2 of 4)

by rjw in reply to daen [original] on Mon, 03/01/2010 - 17:18

General consensus here over the years is that gable vents can ionterfer with the air flow through the attic.

I've never seen an actual example where that has happened, having looked at 3500+ attics....

======================================== "Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary." Reinhold Niebuhr: 'The Children of Light and the Children of Darkness' http://rjw-progressive.blogspot.com/ ========================================

The party line is that mixing (post #185481, reply #3 of 4)

by DanH in reply to daen [original] on Mon, 03/01/2010 - 19:06

The party line is that mixing gable end vents and ridge vents is not a good idea, since air may come in the gable end and exit the ridge, short-circuiting the flow from gable to ridge.  Dunno how "real" that concern is.

But it shouldn't be that big a deal to install a cheap asphalt-style ridge vent now, then remove that and install the tile vent later.  Probably no need even to close the slit for the ridge vent when when you install the tile vent, but if you want to it would be a simple matter of running some rolled roofing or such across it.


We are like tenant farmers chopping down the fence around our house for fuel when we should be using Nature's inexhaustible sources of energy -- sun, wind and tide. ... I'd put my money on the sun and solar energy. What a source of power! I hope we don't have to wait until oil and coal run out before we tackle that. --Thomas Edison

Thanks for the information (post #185481, reply #4 of 4)

by daen in reply to DanH [original] on Tue, 03/02/2010 - 17:24

Thanks for the information guys. I guess I could seal up the gable vents from the inside as an option as well.

I suspected there might be interference, but wanted to confirm.

Thanks again.

dch