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alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

How to seal gable vents

The inspector suggested that the two gable vents in my attic be sealed to let the soffits do the work.



I don't want to bother removing the actual gable vents as I'd need to do aesthetic exterior work to cover the hole. So it would be a seal from the inside.

Suggestions?


Coma
Thanks Steve
Premium
join:2001-12-30
NirvanaLand

Suggestions?


Plastic trash bag and cardboard.

Edit: Do you have a ridge vent ?

--
Live from NirvanaLand™

jsbaker

join:2002-07-13
Houston, TX
reply to alkizmo
That vent looks like it was added after the house was built, so there may be a reason it was added. I've learned home inspectors quite often don't know what the hell they are talking about.

An inspector is the last person I would listen to about closing off attic ventillation.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to Coma
said by Coma:

Suggestions?


Plastic trash bag and cardboard.

Edit: Do you have a ridge vent ?



There are two of these on top of my roof.
No fans, no power, just a huge vent.

Crescent
Premium
join:2003-01-22
canada
reply to jsbaker
said by jsbaker:

I've learned home inspectors quite often don't know what the hell they are talking about.

My thoughts exactly!
agree!


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to alkizmo
The inspectors thinking is probably that the gable vents are "short-circuiting" the flow process, as it is 'too easy' for the air flow to go directly from the gable vent to those muy-mondo vents you have.

Closing the gable vents will cause the soffet vents to draw, evening out the circulation.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
said by John Galt:

The inspectors thinking is probably that the gable vents are "short-circuiting" the flow process, as it is 'too easy' for the air flow to go directly from the gable vent to those muy-mondo vents you have.

Closing the gable vents will cause the soffet vents to draw, evening out the circulation.

That's what I figured.
So green light on sealing the gables?


cypherstream
Premium,MVM
join:2004-12-02
Reading, PA
kudos:3
said by alkizmo:

said by John Galt:

The inspectors thinking is probably that the gable vents are "short-circuiting" the flow process, as it is 'too easy' for the air flow to go directly from the gable vent to those muy-mondo vents you have.

Closing the gable vents will cause the soffet vents to draw, evening out the circulation.

That's what I figured.
So green light on sealing the gables?

Yeah I heard the same thing. A very trusted friend and contractor of mine also attended a demo on this. Gable vents are not needed if you have a ridge vent and soffit venting. The demo used a fog machine and a plexiglass house model. There were two, one with a ridge vent and soffit vents, and another, the same but with gable vents too. The one with the gable vents had worse airflow as seen by the fog collecting and staying in the attic.

»heating-and-cooling.hardwarestor···ion.aspx


cableties
Premium
join:2005-01-27
reply to alkizmo
I picked up some Owens Corning Pink (1.5") Insulation board, and cut to fit over the Gable and screwed (doubesized washers) them to the Gable frame. Quiets the noise coming in too.

(I have ridge, soffit and thermal vent fan so... Gables are push-pulling without proper venting ... had frost dam on one side as the gables were counter-acting the ventilation up the rafters...)
--
Splat

jsbaker

join:2002-07-13
Houston, TX
reply to alkizmo
Correct, close them up. As was suggested you want something rigid or atleast the least thicker than a trash bag otherwise you are wasting your time.

jsbaker

join:2002-07-13
Houston, TX
reply to cableties
Cableties,

Do you still use your thermal fan with with your ridge vent? I ask becuase I have a thermal fan and two turbines along with about 80% soffit venting but no ridge vent. Before next summer I plan on diy'ing a ridge vent retrofit. I am going to seal up the turbines from the inside but I haven't decided whether or not to block off the fan or leave it alone.


cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7
reply to cableties
said by cableties:

I picked up some Owens Corning Pink (1.5") Insulation board, and cut to fit over the Gable and screwed (doubesized washers) them to the Gable frame. Quiets the noise coming in too.

Why bother with 1 1/2" insulation? You're insulating against uninsulated air space. The insulation is on the attic floor, not the wall and roof.

A small piece of 1/2" insulation, plywood, whatever you have handy screwed to the frame and then sealed to block the air flow. It looks like they forgot the saw when they installed that vent, and just used a hammer, so it's going to be a pain to get it sealed. Great Stuff may be your friend.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
said by cdru:

Why bother with 1 1/2" insulation? You're insulating against uninsulated air space. The insulation is on the attic floor, not the wall and roof.

A small piece of 1/2" insulation, plywood, whatever you have handy screwed to the frame and then sealed to block the air flow.

Agreed on the insulation. And even polystyrene wouldn't necessarily resist a strong wind gust.

Got plenty of solid wood boards and plywood laying around. I will cut one of those + sealant tape on the wooden frame of the gable. Then put in some decking screws.

At least from the sort of suggestions I'm getting, there doesn't seem to be a specific procedure, just common sense to apply.

said by cdru:

It looks like they forgot the saw when they installed that vent, and just used a hammer, so it's going to be a pain to get it sealed. Great Stuff may be your friend.

Couldn't I just make a nice clean cut around that hole so it's perfectly flat and square, then seal that up? It's not like we're trying to prevent poisonous gas from coming in.


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3
reply to alkizmo
said by alkizmo:

That's what I figured.
So green light on sealing the gables?

Silly question, but do you have adequate soffit vents?


cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7
reply to alkizmo
said by alkizmo:

Couldn't I just make a nice clean cut around that hole so it's perfectly flat and square, then seal that up? It's not like we're trying to prevent poisonous gas from coming in.

Yes. It doesn't even need to be all that flat and and all that square. Some leakage isn't going to hurt all that much either.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to mattmag
said by mattmag:

Silly question, but do you have adequate soffit vents?

16 inches of soffit paneling all around the roof. Cannot be more "soffited"

Hellrazor
Bah Humbug

join:2002-02-02
Abyss, PA
reply to alkizmo
How about a picture of the soffit vents. Maybe the gables were added due to the lack of proper soffit vents...


leibold
Premium,MVM
join:2002-07-09
Sunnyvale, CA
kudos:10
Reviews:
·SONIC.NET
said by Hellrazor:

Maybe the gables were added due to the lack of proper soffit vents...

Or so opposite. My roof is L-shaped and there are soffit vents all around the house. However instead of ridge vents (which are considered the best option) I only have a pair of eyebrow vents (fairly high) on the longer leg of the L and a gable vent on the end of the shorter leg. In this case the gable vent is clearly to substitute for the lack of proper ridge venting.

Edit: it is hard to tell from the picture, but it looks as if his gable vent is in the upper 3rd of the roof which would make it more of an exhaust vent then an intake vent (similar to mine).

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mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3
reply to alkizmo


"Soffit paneling" all around the roof means nothing if there is no path through the rafters. You need to be sure that there are baffles in place to hold back the insulation and give it space to breathe. I had a house where the soffit looked beautiful, but it was closed up tight as a drum above it.....

Just something to make sure of, and not just go by looks is all I am saying.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1

1 recommendation

said by Hellrazor:

How about a picture of the soffit vents. Maybe the gables were added due to the lack of proper soffit vents...

said by mattmag:

"Soffit paneling" all around the roof means nothing if there is no path through the rafters. You need to be sure that there are baffles in place to hold back the insulation and give it space to breathe. I had a house where the soffit looked beautiful, but it was closed up tight as a drum above it.....

Thanks for the concern

1 - I'm pretty sure the soffits are as recent as when the roof was redone in 2007 by the previous owners. I found extra soffit panels in the shed. They looked recent (Certainly not original from 1964).

2 - There was a good clearance between the soffits and the already existing insulation, well, it was only 5 inches, whoop-tee-doo.

3 - I installed baffles as I'm adding R40 (11") batts to the attic. God damn it was more hassle than laying batts, as I needed to get really far on the edges of the attic, where there's only 2 feet of clearance due to the very low incline of the roof. I was doing it mechanic style, on my back

MaynardKrebs
Heave Steve, for the good of the country
Premium
join:2009-06-17
kudos:4
reply to alkizmo
said by alkizmo:

said by mattmag:

Silly question, but do you have adequate soffit vents?

16 inches of soffit paneling all around the roof. Cannot be more "soffited"

Ok - lesson time.

If your house is 'older' then the soffits were probably made using solid plywood or even tongue & groove boards - and NO ventilation holes.

If the wood is still visible, count how many ventilation holes there are in the soffit and calculate the number of square inches the holes total up. That number of square inches of ventilation holes in the soffit should more or less equal the number of square inches of ventilation holes cut in the roof/gable vents.

Here's where it gets interesting.....

Lots of homes have perforated aluminum or vinyl soffits, but if it's an older home the aluminum/steel/vinyl was typically added so the homeowner simply didn't have to paint the soffits every 15 years. Usually there were NO holes cut in the original wooden soffits when the aluminum/steel/vinyl soffit material was installed - especially if it was installed say more than 15 years ago.

So just because the aluminim/steel/vinyl soffit cladding might have ventilation perforations, that is NO guarantee that the soffits are actually 'breathing'.


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
said by MaynardKrebs:

So just because the aluminim/steel/vinyl soffit cladding might have ventilation perforations, that is NO guarantee that the soffits are actually 'breathing'.

Nice lesson. I'm still not done putting up insulation in the attic, so there's a few baffles not put up yet. I'll try to really squeeze in there to see what's the soffit situation (In day time). If I see plenty of light coming through, it's fine?


Telly Boot
Premium
join:2002-05-15
Vancouver, BC
reply to alkizmo
I would guess that those big gable vents were put in for additional cooling in summer, whereas soffit ( and roof) vents are primarily to allow humidity to escape and prevent problems related to dampness/condensation.
I wish I had those as my low-pitch roof is the size of a tennis court and difficult to vent: so I have been trying to figure out where I can cut the gable and install an attic vent fan- however the gables are a really tough white stucco and there isn't much room [it's on my to-do list]. It was built 40 years ago without ANY roof vents and I had to argue with my torch-on roofing contractor to get six roof vents put in: the soffits are also painted, ...which is common and also reduces their efficiency.
If the gable vents you show are made of plastic (?) and were left in place they could become oxidised and brittle 8-10 years after installation and could start to disintegrate at that point, which would be awkward if they shattered during a blizzard, for example. Can you show a photo of the vents from the outside?
--
Dawn,n,The time when men of reason go to bed. (Ambrose Bierce.)

MaynardKrebs
Heave Steve, for the good of the country
Premium
join:2009-06-17
kudos:4
reply to alkizmo
said by alkizmo:

said by MaynardKrebs:

So just because the aluminim/steel/vinyl soffit cladding might have ventilation perforations, that is NO guarantee that the soffits are actually 'breathing'.

Nice lesson. I'm still not done putting up insulation in the attic, so there's a few baffles not put up yet. I'll try to really squeeze in there to see what's the soffit situation (In day time). If I see plenty of light coming through, it's fine?

Probably. If you have to, pop off some of the slotted panels and cut holes in the wood above. You can use a 3-4" hole saw attached to a drill - try to space the holes fairly evenly along the length of the soffit. Don't hit any joists!!!!


alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to alkizmo
I will try to take a picture tomorrow, right now it's pitch dark.

As for drilling soffits if they are blocked.... ugh, no way am I doing that from inside the attic.


windeeeeee

@telus.net
reply to alkizmo
For people who want to know about that big ridge vent. Designed to stay above the snow and vent all winter, unlike those low profile vents that mostly stop working when the snow covers them.
»www.ventilation-maximum.com/Engl···301.html

More home maintenance tips at...
»joneakes.com/


The Pig
I know you want to be me
Premium
join:2009-09-11
reply to alkizmo
Gable = intake of air
Vent on roof = output of air
You have to circulate the air in the attic to pervent moisture buildup!!


workablob

join:2004-06-09
Houston, TX
kudos:3
Reviews:
·Comcast
reply to alkizmo
said by alkizmo:

said by John Galt:

The inspectors thinking is probably that the gable vents are "short-circuiting" the flow process, as it is 'too easy' for the air flow to go directly from the gable vent to those muy-mondo vents you have.

Closing the gable vents will cause the soffet vents to draw, evening out the circulation.

That's what I figured.
So green light on sealing the gables?

Assuming there are soffet vents. My house has no soffet vents.

Sealing my gable vent would be a bad idea.

Dave


DataDoc
My avatar looks like me, if I was 2D.
Premium
join:2000-05-14
Martinsburg, WV
Reviews:
·Comcast
·Suddenlink
reply to mattmag
said by mattmag:

"Soffit paneling" all around the roof means nothing if there is no path through the rafters. You need to be sure that there are baffles in place to hold back the insulation and give it space to breathe. I had a house where the soffit looked beautiful, but it was closed up tight as a drum above it.....

Just something to make sure of, and not just go by looks is all I am saying.

Exactly what I found when I was mounting my satellite dish. Took off 3 panels and found plywood underneath. Now I've got to take it all down to see if any are able to actually vent anything. Some may, because I see light at some places. I figure a circular saw set to 3/8" ought to let me slice openings above each one.
--
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Thespis
I'm not an actor, but I play one on TV.
Premium
join:2004-08-03
Keller, TX

1 recommendation

reply to The Pig
said by The Pig:

Gable = intake of air
Vent on roof = output of air
You have to circulate the air in the attic to pervent moisture buildup!!

Vent on roof = output of air
Soffit vents = intake of air
Gable vents = old technology that is in the way of proper ventilation and need to be closed.
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