Is it a problem for vapour barrier to be cut when adding pot lights?

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Posted by: from Calgary
1/24/2015 at 8:26:51 AM

We're having 4 pot lights and two pendants installed in the kitchen. The ceiling has an insulated attic above it. Is it a problem, because the vapor barrier will have to be cut?

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Suzanne from Built By Pros Inc. in Toronto
Date/Time1/24/2015 at 10:14:42 AM

You will need to add the blue plastic boxes above each pot light. And tape them to the existing vapour barrier with red Tuck tape in order to seal the surface for air leakage. They sell the blue plastic covers at Home Depot or electrical supply places.

Keep in mind that this work will require removing a large portion of the ceiling if there is not enough room in the attic to work. Also the new pot lights will need to be the type that are encased in a galvanized metal box, not the small retrofit pot lights.


Built By Pros Inc.

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Date/Time1/24/2015 at 10:19:25 AM


That's a great response. I just wanted to clarify to make it easier for you when shopping for the pot lights that you are looking for. Get the ones marked I.C rated.

Best of luck on the project.

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Date/Time1/24/2015 at 1:28:33 PM

Yes you can unseen cut a 2 by 2 foot section for each pot light, keeping in mind that if it trusses it will be 24 in centres but if it is hand cut in could be 16 inches centers.

Then yes get the plastic boots required from your local Home Depot and red tuck tape.

Have a great day.


Pro Drywall

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Date/Time1/24/2015 at 6:22:29 PM

Hi Cari,

I have always been a firm believer in overkill when it comes to safety.

I strongly suggest that you have someone go into the attic space and add the steel box units for pot lights to sit below. These add a much greater amount of air space around the pot lights themselves. And the bulbs will not burn out as fast either because you will keep the temperature cooler by the light.

Be sure to install insulation over the units or you will have cold spots in the ceiling.

James Fram

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Date/Time1/29/2015 at 9:40:30 AM

Hi Carl

Your potlights will likely be installed by an EC. While the attached picture is not exactly the same as your situation, it is close enough so you get the idea.

In your case the blue box will be on the other side of the vapour barrier and tapped from the top.


John Kuehnl-Cadwell

Master Electrician

Datawise Solutions Inc

Is it a problem for vapour barrier to be cut when adding pot lights?

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