Air-sealing JB's after rough-in

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goldstar

goldstar

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Electrical Contractor
I doing a complete 1st floor remodel at a residence. I have not installed any air-tight JB's but I'm thinking in advance in case the EI or BI suddenly and mysteriously decides they want air-tight JB's installed in the outside walls. The air-tight JB's that I see on the market seem quite expensive. Is there an after-market seal or flashing that can be installed after the insulation is on and before sheet rock is installed if I have to do this?
 
In northern Colorado, we have a pretty strict energy code.
The EC's use standard plastic or fiberglass boxes and after the rough, the insulators squirt a shot of foam in the holes to seal them.
However, (there's always a however in life), on a remodel, we don't require a blower door test as the rest of the house may not be as air tight as the remodel. It doesn't make sense.
Good luck.
Ron
 
rc/retired said:
In northern Colorado, we have a pretty strict energy code.
The EC's use standard plastic or fiberglass boxes and after the rough, the insulators squirt a shot of foam in the holes to seal them.
However, (there's always a however in life), on a remodel, we don't require a blower door test as the rest of the house may not be as air tight as the remodel. It doesn't make sense.
Good luck.
Ron
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I think it's an issue of making the wall cutout airtight
They make outlet boxes with a gasket molded onto the edge

 

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JoeNorm said:
Just get the proper boxes now. How much could the extra expense really be?
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Sorry, I didn't mean to mislead you. It wasn't so much about the $$ as it was about the EI. This is the same guy who failed me on a service upgrade for driving ground rods at too severe an angle and wanted to witness me torquing the lugs in the MBP. I was just trying to anticipate getting my chops broken and whether or not I had an out.

Also, I like to use adjustable boxes for kitchens. HO's always seem to want to install a tile or granite back-splash AFTER the fact so, I like to be prepared and be able to adjust the box out. I'm not sure they make adjustable boxes that can be sealed
 
Looks like it snaps over the plastic box, before drywall, and the foam gasket on the face seals to the backside of the drywall.

meproducts.net

Draft Seal

Look for the green seal.
meproducts.net meproducts.net

Cheers, Wayne
 
There are several potential issues here. Well, two I guess:

1. Local energy code requirements - In some areas I know the EI's enforce energy codes that relate to the electrical installation.

2. building envelope considerations - In cold climates where permeable insulation such as fiberglass or rock wool is used, it is very important that there is an air seal. If the air seal is compromised, when air convects from the hot space to the cold space it will loose its moisture. Its really quite alarming to see. This one job last year was insulated but not drywalled and it was winter, and the building was heated. I had to make a few minor changes to my rough and when I pulled out some insulation, the cold side and the exterior sheathing were saturated with water. Depending on some specifics, craft paper facing can be the vapor retarder, or the painted drywall can be. In either case it is very important to seal around the electrical boxes. This job, no one else did it so I absolutely foamed the punch outs and caulked around the boxes on all exterior walls.
 
JoeNorm said:
Just get the proper boxes now. How much could the extra expense really be?
Click to expand...

MORE... more cost for the boxes (wall and ceiling) and they're a pain in the neck to work with (at least the ones I used). The plastic push in connectors easily kept falling out, and they looked like they would really push the sheetrock out so I took a wood chisel and chiseled out part of the stud or joist as to decrease the bulge. I planned on regular boxes when I bid the job then when I was going to do the work I decided to use vapor boxes because "how much could the extra expense really be"? MORE....MUCH MORE.
 
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Most of the construction here (or at least most of the contractors I work for) in central NY use closed cell spray foam insulation, so this is a non issue. For projects using fiberglass or rock wool, I just use standard boxes and caulk and foam them. This would only be on exterior walls and I find it takes negligible time. Sometimes I can pawn off the task to the GC and he will take care of it.
 
AC\DC said:
Dumb question, is this some local requirement, or specs on plan. Never heard of air tight junction box
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There are some towns in NJ that require these. It's usually enforced by an EI who arbitrarily found out or read somewhere in the Energy Code that these boxes should be used. In my township the BI told me that if the house is wrapped in Tyvec OR if you don't break the vapor barrier when installing insulation you don't need the vapor tight boxes. Generally speaking, I don't care one way or another as long as I know I'm required to use them UP FRONT. It becomes a real PITA if you have to remove the all wiring and all the ground crimps if the EI comes in and tells you they are required. That's why I asked if there was an after-installation product that would accomplish the same type of seal.
 
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