# Can I insulate this void above my garage door to stop air getting into room above?



## Tymbo (Jan 18, 2018)

It should be a solid header.


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## Bud9051 (Nov 11, 2015)

As tymbo said, it should be a solid header.
A couple of issues. 
Air from a garage getting into living spaces above is a serious safety hazard as vehicle exhaust can be dangerous.
Now, above that header are the floor joists and if you are feeling air above it is coming from that cavity, probably not the garage. Just a guess.

How is that cavity, the floor joists, insulated. Search for some framing details for floor over a garage door and you'll see what I mean.

Bud


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## Rav (Dec 7, 2011)

Bud9051 said:


> As tymbo said, it should be a solid header.
> A couple of issues.
> Air from a garage getting into living spaces above is a serious safety hazard as vehicle exhaust can be dangerous.
> Now, above that header are the floor joists and if you are feeling air above it is coming from that cavity, probably not the garage. Just a guess.
> ...


Thanks, Bud.

Perhaps it is solid, but it sure SOUNDS hollow, which is why I thought the air was coming in from there. At any rate ...

I agree that the air is probably not coming from the garage, especially since I recently insulated all the joist bays above the garage (below the bedroom) with blown in cellulose, including the one right next to and parallel with the garage door. There was no insulation in there until I did that. I also air sealed each bay where it met the exterior wall.


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## Bud9051 (Nov 11, 2015)

A header for a garage door (2x4 wall) could be a double 2x? which would be only 3" thick. They would add a 2x? at the bottom for nailing the drywall and the top would have a double top plate. That would leave a ½" air space behind the drywall and give you the hollow sound. Pokes a small nail through or a drill bit to see if it hits the header back there.

Normal winter air flow is in through the lower portions of the house, up through the structure, and out the upper areas. Filling with cellulose will slow the air flow down but will not stop it. More investigating is needed to locate the source of the cold air. Note, living space over a cold garage it always a difficult area to keep warm.

Does the house overhang the foundation?

Here is a link with many detailed images of framing over garage doors.
https://www.google.com/search?clien......0...1c.1.64.psy-ab..0.0.0....0.qLVQ5otklhw

Bud


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## Rav (Dec 7, 2011)

Bud9051 said:


> A header for a garage door (2x4 wall) could be a double 2x? which would be only 3" thick. They would add a 2x? at the bottom for nailing the drywall and the top would have a double top plate. That would leave a ½" air space behind the drywall and give you the hollow sound. Pokes a small nail through or a drill bit to see if it hits the header back there.
> 
> Normal winter air flow is in through the lower portions of the house, up through the structure, and out the upper areas. Filling with cellulose will slow the air flow down but will not stop it. More investigating is needed to locate the source of the cold air. Note, living space over a cold garage it always a difficult area to keep warm.
> 
> ...


Bud -- From what you and Tymbo have said, this may not be a good thing, but I did what you suggested and drilled a very small hole into the plywood (not drywall) that covers the area in question inside the garage. The bit very soon hit empty space. I then inserted some 18 AWG wire into the hole, and it went in 8-1/4" before hitting the other side. See attached pics.

If it makes any difference, I'm pretty sure there is a metal lintel embedded at the bottom of the stone exterior above the garage door.

I'm not sure what you mean when you asked "Does the house overhang the foundation?"


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## Bud9051 (Nov 11, 2015)

I went back to the pictures and didn't see an overhang but did see the stone siding. I will admit, I don't know how that header was constructed. Since you started with plywood at the inside surface, maybe an I-joist plus the metal lentil outside, but I agree probably hollow from what you found.

Do you have any engineering drawing for the house? Sometimes the original plans are on file at tour town office building department.

Bud


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## Rav (Dec 7, 2011)

Bud9051 said:


> I went back to the pictures and didn't see an overhang but did see the stone siding. I will admit, I don't know how that header was constructed. Since you started with plywood at the inside surface, maybe an I-joist plus the metal lentil outside, but I agree probably hollow from what you found.
> 
> Do you have any engineering drawing for the house? Sometimes the original plans are on file at tour town office building department.
> 
> Bud


Thanks, Bud. No, don’t have any plans for the house. Since it does seem hollow, do you think it’s OK for me to persue my idea of blowing cellulose in there, and do you think it would help the air flow issue? Since the plywood is nailed up in sections I expect there are multiple “compartments” in there that I’d need to fill separately.


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## Bud9051 (Nov 11, 2015)

I'm just guessing, but only issue I see is the normal space behind a layer of brick (stone in your case) needed to help that space dry. Without details as to how that assembly is constructed is is hard to say. Not sure if that plywood is structural of just covering a gap.

Bud


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