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p.millette 04-14-2012 10:41 AM

Ridge Vents...No Soffit Vents?

My wife and I bought this six year old 3 story house in the Georgia mountains a couple of years ago.
Last summer we didn't have any problems cooling the house and all seemed ok.
However, when winter cold and high winds came, we noticed some weird drafts on all three and out of the central HVAC ductwork, under and around inside doors etc.
We hired a HVAC contractor to install a new gas furnace and check all the ductwork.
The ductwork passed the test but the House Pressure Test failed and we're all trying to figure out why.

There's a ridge vent on the roof but I can't see any soffit vents (no attic).
Can anyone offer any insights on how the ridge vents work without soffit vents and if this could be a factor in the weird drafts situation?

Thanks, P. M.

joecaption 04-14-2012 10:47 AM

Soffit vents are needed for ridge vents to work but should have nothing to do with floor drafts.

I'd be taking a look at the foundation vents, make sure the access door is in place, insulating the sill plate areas, air sealing any holes in the subflooring or bottom plate areas where wires or plumbing was run, insulating under the floors.

If this is a really old house with hard wood floors directly attached to the floor joist or there's just 1 X 6's for a sub floors there's hundreds of places for air to get in so the insulation would sure help under the floors.

p.millette 04-14-2012 11:45 AM

Thanks Joe:

The house is only 6 yrs old and I guess if there are no soffit vents, the high winds are sucking air from the house is built on a slab with three seperate floors and one very high vaulted ceiling on second floor.
I guess I'd better put on my detective hat and look at where the ridge vent is getting air during high winds.

Thanks again, P.M.

joecaption 04-14-2012 11:47 AM

Post a picture of the outside of the house.

p.millette 04-14-2012 11:50 AM

I'll get a pix maybe later today.

P. M

Ironlight 04-14-2012 12:08 PM

It's interesting that you had and HVAC professional do a pressure test, yet they were not able to determine the source of the air infiltration. That's not a good sign because they are professionals and likely eliminated all the obvious potential sources and the ones that you can easilyh do something about. It could mean that in fact it is coming from all over, i.e. uninsulated window casings, poor house wrap job gaps in the sheathing, etc.

If you continue to be stumped you might want to call an outfit that does energy audits and inspections. They'll repeat the pressure test but are better equipped to determine where your leaks are.

And the lack of soffit vents will only be a contributing factor if air from the dwelling can easily move to the unconditioned attic space. Is there an air handler up there with a return that goes to it, an attic door, a pull down stairway, or recessed lights in the third floor ceiling?

House Engineer 04-14-2012 12:25 PM

To answer your main question first: ridge vents do not work without soffit vents.

I thought that the HVAC guys used a smoke test, not a pressure test, to locate interior air flow.

seeyou 04-14-2012 02:22 PM


Originally Posted by House Engineer (Post 898788)
To answer your main question first: ridge vents do not work without soffit vents.

I thought that the HVAC guys used a smoke test, not a pressure test, to locate interior air flow.

Au contraire, Mon Frere. They won't work like they're supposed to, but can cause conditioned air to be sucked from the living space if the ceiling plane is not air sealed.

House Engineer 04-14-2012 02:48 PM

If that post is directed to me, that is not what I call "working". (I meant working "properly").

p.millette 04-14-2012 04:02 PM

Hi all,
Thanks for the input.
I have a meeting with HVAC folks this week before I pay them...
In the meantime, I'm trying to figure out how to send a pix of the problem house.

Thanks for any help,

p.millette 04-14-2012 04:07 PM

1 Attachment(s)
Hi Again All;

I think the pix will work this time.


Ironlight 04-14-2012 04:37 PM

Where you have "no vents" in your picture is not where you would find soffit vents. You would find a "gable vent" there (see picture below). Soffit vents are right under the eaves, just inside from the gutters. It's hard to tell from that photo whether you have them or not, at least on the side opposite the porch.

Here is a soffit vent. They can be continuous, or be smaller vents, somewhat like AC vents, set at intervals along the eave:

p.millette 04-14-2012 09:43 PM

Thanks Ironlight,
You're right but there aren't any soffit vents anyplace on the house....and no attic either. Maybe no ventilation space exists...but why the ridge vent?

At this point I think the third floor tongue and groove ceiling is seperated from the roof by only the insulation air space.

When the wind howls across the roof, I'm thinking a venturi effect kicks in and sucks air out of the living spaces.
I'm tempted to drill a small hole in the soffit under the eave and see if I can monitor the pressures somehow.

Getting to be a real science project!

Take care & tnx,

seeyou 04-15-2012 07:01 AM

There may be a small airspace above the insulation. In that case, there should be some sort of inlet provided.

When you say "there is no attic", do you mean the ceiling (drywall,etc) is attached to the rafters - a sloped ceiling?

p.millette 04-15-2012 07:30 AM

Hi Again Ironlight;

Yes, that's correct...very high sloped ceilings all over the house.


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