Garage floor joists - sealing openings

[mossyoakglock]

Garage Ceiling joists - closing/sealing openings to crawl space

We had the interior of the garage extended back into the crawlspace and when they put up the new walls, it left some openings above the new walls at the ceiling joists. I am pretty sure this is where my moisture issues is coming from. Before it was sealed off since the original wall ran with the joists but now the new walls are perpendicular with how we had to do the walls.

I was thinking of just cutting some 1" thick insulating foam to fill the gaps and the seal around the edges in hopes this would seal off any moisture coming from the crawl space. I've added some pictures of what I'm talking about.

If the insulating foam isn't a good choice, any other suggestions.

 

[nadogail]

Is that daylight I am seeing between those floor joists?

 

[mossyoakglock]

No, that is the light coming from inside the garage. The concrete wall is the exterior wall. The right side wall is the interior garage wall. Where the light is is what I'm wanting to seal.

I was thinking of just using some 1" foam board to fill the openings.

 

[Sawdust_]

Rigid insulation with the perimeter foamed in with Great stuff will make an excellent air vapor barrier.
It's what I used on the rim joists in my basement and it's as effect as sprayfoam insulation but its an easy DIY approach.

 

[Leaflessshadetree]

It appears that you have created a small space between the garage wall and the house wall. Are there spaces between the joists at the top of the concrete wall?

If no then and that space is where you have moisture issues I'd add some ventilation at the bottom of the garage wall. (Actually if it is not load bearing I'd remove the garage wall to have the extra space in the garage)

 

[firebirdparts]

Rigid insulation with the perimeter foamed in with Great stuff will make an excellent air vapor barrier.
It's what I used on the rim joists in my basement and it's as effect as sprayfoam insulation but its an easy DIY approach.

I have to say I do this all the time, because the rigid insulation is just so easy to work with. However, I don't know if it's because I'm smart or stupid. I haven't had any obvious regrets. Both my house and my shop are one-and-a-half story buildings, and that style of construction is so difficult to seal geometrically.

 

[rburke65]

I would think you could use the rigid Insulation.