Search the forums

Loading

Wind+Rain vs Ridge Vent

EricPaulson's picture

I was sent up into an attic this morning in a fairly new but decently constructed house.


In one of the bedrooms below the attic there was very slight water damage right at a taper joint in the ceiling drywall.


HO was guessing it had something to do with the ac up in the attic cause she noticed it soon after the hvac guy ran two new branches into a bounus room.


As I was poking arounf I could not see any eveidence of a leak in any of the flex ducts near the sigh of the leak but I did detect a little water on top of the insulation directly over the damge and pretty much directly under the ridge vent. And, it had windyrained last nite.


This house is waaaay up on a windswept hill (small mountain).


How do we deal with this if in fact it is blowing in through the ridge vent?


Thanks


 


 


"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

 

 

"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

(post #86222, reply #1 of 24)

What top of ridge vent?
Stephen

(post #86222, reply #4 of 24)

It's some type of shingle over vent. I don't think it's that cobra stuff but I cannot tell till I get up there if I do.

 


 


"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

 

 

"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

(post #86222, reply #7 of 24)

Reason i ask is that the old style metal air vent types are notorious for leaking at the exposed fasteners AND at each section as It joins the next piece.

this spring I encountereds a leak in a section of cor-a-vent which I have used problem free for 20 years or so--- stuff was just filled with water-just sopping wet.

It was on a breezeway type roof between main house and a secondary structure---- and very minimal soffit vents-- NOT a balanced vent system at all--- actually just a total of 5 of those little round soffet plug vents in combo with maybe 15-20 feet of coravent. the cora-avent just sucked the water right in in a very heavy wind on about a 5/12 pitch.

stephen

(post #86222, reply #8 of 24)

The sophits seem to be well vented so I would not think that the air would not flow.


If the wind were blowing the right way past the sophits could it create negative pressure enough to suck in rain through the ridge vent?


This place is up there, very near by one of the toughest climbs (bicycle) around.


It's not at the top, but on the way up and faces the valley below, squarely.


 


 


"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

 

 

"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

(post #86222, reply #9 of 24)

I could be wrong, but my impression was that it worked the other way around....that if there were more square inches of sofffit area than ridge or roof vent area, that the venturi affect of wind blowing by the soffit would pull in water through the top.


It might be the way you were holding your ladder...:)


Bing

(post #86222, reply #12 of 24)

bing,
i am only reporting what I encountered--- but I think physically I am never gonna encounter more soffit vent than ridge vent.

coravent used to make- and maybe still makes a vent with a wind activated flap---wind blowing from the west?- west side vent closes and air pressure pulls exhaust out the east side of the vent.

If I can--- i try to avoid ridge vents on our older houses since they really were never set up with soffit vents etc.

See grants post.
stephen

(post #86222, reply #2 of 24)

That's a good one I always wondered about myself. Maybe some sort of baffle? Not sure what or how. Or I wonder if both sides of the vent are necessary, maybe the side facing predominat winds could be closed off?


Just a thought. I'd be pretty interested in what others have to say.


~ Ted W ~


Cheap Tools! - MyToolbox.net
Meet me at House & Builder!

~ Ted W ~

(post #86222, reply #5 of 24)

Interesting thought 'cause the ridge line I'd say is just about perpendicular to the valley below.


I think most of the current is blowing out of the valley up the mountain.


 


 


"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

 

 

"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

(post #86222, reply #16 of 24)

If it appears to be water blowing up a valley then it might be wise to block the ridge vent in that area, on the one side.

Normally ridge vents have a baffle that prevents blowing water from getting in, but you could have A LOT of water blowing up a valley and it could overtop the baffle.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #86222, reply #17 of 24)

Dan, i think the valley he is referring to is a valley in the landscape and surrounding terrain.

I don't think a ROOF valley would be a consideration here as ridge vents are generally stopped several feet from a roof valley
stephen

(post #86222, reply #18 of 24)

Normally should be, but you never can tell.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #86222, reply #21 of 24)

That is how I read it. I've been on roof in mountain locations like that were the wind there would take a shingle wrapper and make it dance the twist right over top of the ridge. No predicting exactly what it might be doing at any one minute. I have been in attics with nail over ridge vent and seen snow pellets being blown in, so I never believed the ridge vent keeps all the water out. I just assume that in most cases, the amt blown in is minimal and evaporates again before there is enough to damage ceilings in most cases.

Eric could always staple a plastic bag under the drip to catch it so it doesn't stain the ceiling, LOL

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #86222, reply #22 of 24)

Eric could always staple a plastic bag under the drip to catch it so it doesn't stain the ceiling, LOL


You laugh! I actually thought about building a metal trough beneath it to catch the water.


 


 


"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

 

 

"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

(post #86222, reply #20 of 24)

In a location like that, you can get a pretty strong whirling eddy of wind, like a mini tornado or dust devil, so direction means little. You can install baffles a few inches below the open edge of ridge vent. Have the metal bent to be about 2" high an enough to slip up under. Then glue it in place under a shingle edge or the RV edge. Leave a few breaks so rain on the ridge and drain away. Prepaint it to match colour

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #86222, reply #3 of 24)

Did you look at the outside - could be ridge caps got blown off.

http://www.quittintime.com/              

(post #86222, reply #6 of 24)

Grant, I don't think any are missing. I was able to get a decent look from the road but I did not have binocs with me.


I think it's blowing in, but I'll know better when I can get up there.


Maybe time for a nice cupola!


 


 


"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

 

 

"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

(post #86222, reply #10 of 24)

I just had a Lomanco 750 box vent leak yesterday. Never seen that happen when they were installed right and not damaged. It just leaked for  a few minutes when a particularly hard wind was blowing. Roof and vent are about a year old and we've had lot's of harder winds. Strange.


You'd probably have noticed, but the vent may have lifted some in the wind allowing some rain under it if the ridge cap nails weren't long enough.


http://www.quittintime.com/              

(post #86222, reply #11 of 24)

Let's say you went up in the attic and saw water coming in through the ridge vent during a wind/rain event.


What course of action would you suggest?


Am I nuts to suggest that the wind passing by the sophitts could suck the rain into the ridge vent?


Thanks


 


 


"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

 

 

"When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking." — Sherlock Holmes, 1896

(post #86222, reply #13 of 24)

Eric- as it was explained to me at a seminar( and my understanding may be defective)-------- it isn't really the wind passing by the soffit

in the absence of soffit vents-- with a wind or a rapidly changing weather system- you can occasioanlly get in a situation where the pressure inside the attic is lower than the pressure outside----so in effect you have a vacume in the attic sucking air IN the ridge vent

WITH a soffit vent balanced- in and out pressure equalizes quicker-- it's a whole different action then the standard cool air enters at the soffit and rises to the ridge scenario

but I can certainley be wrong
stephen

(post #86222, reply #15 of 24)

Let's say you went up in the attic and saw water coming in through the ridge vent during a wind/rain event.


What course of action would you suggest?


1st, I'd have to get on the roof on puruse the situation. If it's never done it before, my 1st thought was that something's changed. I'd try to find out what that something was.


http://www.quittintime.com/              

(post #86222, reply #14 of 24)

Grant- i don't think we have ever seen a slant back leak either if installed correctly------ and rarely an incorrectly installed one leak.

If a customer with an older homes has slantbacks- generally i preferr to keep that style-- because i don't really see them harming anything

in theory-- ridge vents are less leak prone( water landing on the roof below them)---- but occasionally you see these funky pressure situations. one of my roofing suppliers used to have a couple hundred feet of metal airvent that leaked almost every heavy rain--right into the warehouse!
Stephen

(post #86222, reply #19 of 24)

Most rigid plastic shingle over ridge vent has a baffle along the bottom edge that is supposed to prevent leakage from wind blown rain.  This picture shows it but not very clearly.  If you scroll down and left click on the drawing and magnify it you can see it better.    When looking at the drawing also notice the "built in end plug".


For your situation, a trip to the roof is required, but you should be able to identify what type of ridge vent it is by looking at with a pair of binoculars, and when in the attic, by shining a flashlight up at the gap in sheathing at the ridge.  If it is the rigid plastic type you will either be able to see the black plastic with a gap below it or some has a (white?) filter material in it that is somewhat like the spun fiberglass material in a furnace filter.  If it is the roll out cobra vent stuff it will be a coarse black sorta spongy looking material.

Matt

(post #86222, reply #23 of 24)

It should be noted that Cobra also makes the rigid units. But the name "Cobra" has kind of stuck to their roll mesh stuff.


The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #86222, reply #24 of 24)

With those hardstyle Venturi vents I've seen bees work their way underneath the baffles where an old roof didn't let the baffle rest complete flush on the shingle.


Ripped pieces of Cobra to stick behind the baffles to finally run them off. 


half of good living is staying out of bad situations