# Boxing recessed lighting for insulation



## Bob Mariani (Dec 1, 2008)

Some people will do it. Just a plywood box over the recessed part of the fixture. Not needed if you have IC cans. These are somewhat newer and contractors learned from grand dad and never learn to think and learn what and when something is needed.


----------



## DUDE! (May 3, 2008)

Bob, I'm curious on this issue, don't need it written in stone but what kind of space are we talking, I understand there are different size cans but what kind of room should you leave when making these boxes, would be a whole lot easier then replacing the cans, thanks for any help


----------



## Scuba_Dave (Jan 16, 2009)

Some cans are air-tight, some aren't.
So possibly trying to cut down on air infiltration?
That only works if the box is sealed


----------



## Termite (Apr 13, 2008)

Can lights are definately air leakers. They do make "air-lock" cans, which are more airtight supposedly. I've seen a number of people build boxes around them with wood and/or drywall, with caulked seams. Personally, I wouldn't go to the trouble, but I can see that there could be some benefit.


----------



## Bob Mariani (Dec 1, 2008)

If these cans are not IC cans you need a least 2" around and above them. And caulking the seams is the way to go. If they are IC cans, not box. The insulation will go around them and over them.


----------



## DUDE! (May 3, 2008)

thanks for the info, I'll wait until it warms up some in the attic to do this. It's probably not much but I do notice that when the snow on the roof is melting away, the area over two can lights, next to an exterior wall are noticable. I figure building some covers over them is easier then replacing them, either way it'll be a tight working area.


----------



## Scuba_Dave (Jan 16, 2009)

Do cans have a thermal sensor?
IE if the inside hits a certain temp the light shuts off?
My bathroom light has that feature, I use a CFL now - 100w used to kick it off


----------



## jaros bros. (Jan 16, 2009)

I remember seeing an advertisement for styrofoam covers that fit over the can to deal with just this problem. You then sealed around it with a can of spray foam. It looked like a great idea.
On another note, those cans rated IC sure do scare me. What's the deal. They can get very hot, even using the right rated bulb and all. And the crazy thing is that to make them IC, all you do is take the label off of them that says they are not IC. What's the deal? I was thinking the trim details allow or disallow more heat to dissipate.


----------



## Bob Mariani (Dec 1, 2008)

Thermal overloads have been the law since 1982. IC cans are labeled but they are also silver not white so electricians and inspectors know the difference. I also noted m typo above. You need 3" clearance around non - IC cans. Although these do not need to be boxed, using a foam box that is sealed will help keep air movement (due to heat rise) containing moisture into your attic space. Review this document for a good review of recessed lights. http://oikos.com/library/recessed_lighting/index.html


----------



## Scuba_Dave (Jan 16, 2009)

Good to know, white & silver - that makes it easier
Would a plastic vapor barrier around a can be a good idea?
Since the rest of the house has a vapor barrier the cans would be holes in that barrier
I think I saw that posted on another thread


----------



## Bob Mariani (Dec 1, 2008)

Scuba_Dave said:


> Good to know, white & silver - that makes it easier
> Would a plastic vapor barrier around a can be a good idea?
> Since the rest of the house has a vapor barrier the cans would be holes in that barrier
> I think I saw that posted on another thread


No.. a big no. The thermal overloads cut out at 184 degrees. I do not think plastic will like that.


----------



## cocobolo (Dec 16, 2008)

Perhaps just going to a CF bulb may help solve the problem. The temperature is much less than incandescent.


----------

