Recess cans in foam Insulation

[bpk]

I just started the RI of a new house. The ceiling is vaulted and the insulator has already sprayed it with foam insulation about 6" deep. The ceiling joists are 12" I joists. My question is to install recess cans (which the owners want)
I would need to cut out a little foam above each one. I know for IC cans they can be in direct contact with insulation but this foam seems like it would be different as it is airtight. Do any of you work around this type of insulation much, and if so have you had any problems with the thermal limit of the cans shutting them off ? Should I leave more of an airspace above them ?
Thanks in advance

 

[Dennis Alwon]

I don't think the foam is an issue as long as you can access the jb once it is installed.

I hate this stuff. If you leave a wire loose in an exterior wall to be cut in the siding at a later date you will be cussing big time. This stuff makes it a bear to cut that box out.

 

[ishium 80439]

The insulators got in there before you roughed it in? I think I would be a little PO'd about that. I think the only answer would be talk to the insulator to see what type of product he is using and than contact the can manufacturer to see what their recommendatios are. I roughed a house this summer where the thermals kept cutting out on the second floor. I had never seen this before where all of the cans were affected. I called the manufacturer and told them the scenario thinking maybe a bad batch of thermals got through (unlikely I know). After a little back and forth we came to the conclusion that they had blown in too much insulation and went beyond the R value that the can was rated for (can't seem to recall the numbers right now). Luckily I was able to get into the attic and move some of the blown insulation from around all of the cansand all has been well since. Since you won't have that luxury I definately suggest coordinating w/ the insulators and the manufacturer. Also if you take too much of the foam away it might compromise their installation in terms of required R value.

 

[480sparky]

Two problems I see with foam insulation & can lights.

1. You must destroy the can in order to remove it.
2. You must remove the foam between the can and the jbox.

Usually, when I find out about a foam where I have can lights, I install the cans after the foam so I can remove the insulation where I need to.

 

[satcom]

Your best bet is to call the can manufacture and ask for theit advice, I hope you had a good contract on this job, so you can recover the additional costs.

 

[marcerrin]

Now your going to have a thermal hole everywhere you install a can light in that ceiling. WTF were they thinking insulating before you? Hope the $$ is good.

 

[Dennis Alwon]

Two problems I see with foam insulation & can lights.

1. You must destroy the can in order to remove it.
2. You must remove the foam between the can and the jbox.

Usually, when I find out about a foam where I have can lights, I install the cans after the foam so I can remove the insulation where I need to.

The op is installing the can after the insulation. This stuff, I believe, is already blown in on the roof rafters not the ceiling joist. He is going to cut away some insulation so the can can fit. I am guessing cathedral ceiling here. So it can be removed.

 

[Pierre C Belarge]

Use a combination "Airtight/IC" can. Most that I am aware of are designed just for this type of situation.


If the lights blink, charge the customer more money...as you have installed lighting/holiday lighting all in one fixtures...they have to be more expensive.

 

[480sparky]

The op is installing the can after the insulation. This stuff, I believe, is already blown in on the roof rafters not the ceiling joist. He is going to cut away some insulation so the can can fit. I am guessing cathedral ceiling here. So it can be removed.

Exactly what I do. A straight-claw hammer works real good.

 

[~Shado~]

If the lights blink, charge the customer more money...as you have installed lighting/holiday lighting all in one fixtures...they have to be more expensive.

Now that is funny!!! Wonder what the new price would be then....