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New Member (Hello)! (Insulating around outlet boxes)

New Member (Hello)! (Insulating around outlet boxes)


Old 12-01-06, 08:14 AM
Thread Starter
Join Date: Dec 2006
Posts: 9
New Member (Hello)! (Insulating around outlet boxes)


I am a new member and reside in Vermont. As you know, Vermont can get cold ie -40F below at times. I have a two car garage where the basement is normally located. It is open front and stick built in the front where the two double garage doors are located with full concrete basement type walls on the two sides and the back with full dirt back fill on these concrete wall portions. Stairs from the basement garage leads up to a large kitchen and family room. It doubles as my workshop so I installed numerous double gang electrical outlet GFI's on all walls. I placed 1 1/2 Dow Wall Mate on the concrete walls. Because the Wall Mate is only 1 1/2 I used shallow plastic outlet boxes. It is all sheet rocked. I noticed water dripping out of two boxes recently during a cold snap. The garage is heated. I pulled the outlets and took a look and all outlet boxes on exterior concrete walls have condensation in them. I used plastic boxes in hopes of avoiding the condensation I have seen others exprience with metal boxes here in Vermont. Because of the nature of the foam insulation and the debth of these walls I cannot insulate behind these boxes. I imagine I could squeeze someting 1/8 thick or less behind the boxes but what. Any ideas? I am sure it is associated with the humidity in the garage from melting snow etc. It is not praticle to operate a dehumidifier 24/7 particularly with the high cost of electricity here. My house averages 200.00 month now with mostly LP everything ( stove dryer etc.) I also need to research a HRV or ERV??? for the very tight house. That is another subject.

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Old 12-01-06, 02:58 PM
Join Date: Oct 2005
Location: Milwaukee WI
Posts: 1,338
Sounds like you need to apply for an exception to the laws of physics. Talk to Capt. Kirk about that one.

While you're waiting for an answer from Star Fleet, can you consider vapor-sealed covers, for example the old snap-cover types that were permitted outdoors before weatherproof-while-in-use became mandatory?

Do you have enough slack cable to cut out those boxes, seal the holes with foam, and reterminate in surface-mounted boxes? I would the guess the insulation wouldn't support the boxes but maybe you could use some toggle bolts thru the new foam to the concrete.

1/8" behind might be enough if you can get some room air circulating behind there without getting it behind the Dow foam. Maybe some stainless diamond mesh!

Good luck.
Old 12-01-06, 04:14 PM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 9,722
No quick fix I'm afraid.

If what you have done is installed the boxes against the cold wall and insulation around the boxes there is no way to fix this except to remove the boxes and get insulation behind them.
You could either rebuild the wall to a normal thickness that would allow insulation to be behind the boxes or remove the boxes from the existing wall, add insulation and then surface mount the boxes.
Old 12-01-06, 04:45 PM
Join Date: Aug 2000
Location: USA
Posts: 15,834
"I noticed water dripping out of two boxes recently during a cold snap." This means you have condensation. Condensation is a result of warm, moist air encountering a cold surface. This is the same as if I poured you a glass of ice tea on a hot summer day as we sat and discussed how great the DoItYourself.com forums are. The outside of your glass would develop condensation and get the table wet. That's why I gave you an absorbent coaster!

You have a heated garage. The air is warm and humid. This has to pass through the wall. If wall does not have a vapor retarder beneath the dry wall and over the insulation, condensation will develop inside the wall cavity. Foam insulation is its own vapor retarder! So, you are good to go in that category.

As GregH states, you need insulation behind and around your boxes. You can remove them, spray in some canned foam insulation. This stuff is expansive and messy. Wear disposable gloves and get it on nothing because there's no way you can get it off anything! Once it sets up, cut out for the boxes to desired depth and width, making sure that they will be nested safely within the magical insulation that provides its own vapor retarder.

In regard to humidity in a very tight home, you need to keep an eye on the level of humidity. Please note that humidity tends to vary from room to room, and it is usually higher in kitchens and bathrooms. Humidity is measured with a hygrometer (sold where thermometers are sold). Humidity is best maintained between 35-55% year round.

High humidity tends to produce mold and mildew issues. For those who have allergies and upper respiratory problems, this can become a really big issue for homeowners. Make sure you have a vapor retarder in attic areas with recommended R-value insulation for your area. And, very importantly, all attic areas need adequate ventilation to prevent moisture, mold, mildew, and other issues. If you want to discuss ventilation, please start another thread.

You do not indicate the type of heat for your garage. That would be good to know because we frequently have DIYers wanting to heat garages and how to insulate garage doors. Please advise how you heat your garage and how you deal with garage door.
Old 12-01-06, 05:35 PM
Join Date: Nov 2001
Location: USA
Posts: 1,873

Pose your question here, if they don't come to your home and find the source of the problem, they will know someone in your area that will.
Old 12-02-06, 12:35 PM
Thread Starter
Join Date: Dec 2006
Posts: 9
Thanks for all the responses! It seems to me that surface mount is the way to go. Being that the box is plastic, I believe I can cut the tab off pull the box, fill the cavity with the same wall mate isulation and then surface mount.

I may try insulated covers as a last resort before pulling the boxes though!

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