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wilsonfrench 01-15-2009 12:39 AM

heat from home underside roof
 
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I have a question about heat from a light fixture. Can it emit enough heat (radiate heat) to cause condensation on the underside of my roof? how can i stop this? do I cover it with insulation? can it (the octagon box) be covered with insulation? thanks

see photo

the roofing god 01-15-2009 06:14 AM

don`t caulk the holes on the electrical box,and don`t coat the electric box with foam either,simply put the fiberglass batts over the electrical box
the heat from the light causing problems-possibly in connection with the house heat that escapes thru that uninsulated area,always wrap pipes and protrusions with insulation,and cover attic entrance with it as well-be careful of any ceiling high hat lights-DO NOT cover them if they are not stamped IS,which means they`re insulated,if you cover older model,uninsulated ones,you run the risk of fire

wilsonfrench 01-15-2009 10:36 AM

1 Attachment(s)
Quote:

Originally Posted by the roofing god (Post 212939)
don`t caulk the holes on the electrical box,and don`t coat the electric box with foam either,simply put the fiberglass batts over the electrical box
the heat from the light causing problems-possibly in connection with the house heat that escapes thru that uninsulated area,always wrap pipes and protrusions with insulation,and cover attic entrance with it as well-be careful of any ceiling high hat lights-DO NOT cover them if they are not stamped IS,which means they`re insulated,if you cover older model,uninsulated ones,you run the risk of fire

it looks like the picture I attached...can I put insulation on top of that? ...
also, my electrical box feels warm....will that start a fire?

Dragon 01-15-2009 11:07 AM

It would be best if you posted pictures of your actual situation rather than ones found elsewhere. That way comments you receive will be more on target.

In the first picture on your first post you show an electric box, and in the second you show what looks like a large box for recessed lighting. Which one are we talking about?

As stated previously in the comments, if it is a recessed light fixture that is not rated/stamped for "Insulation Contact" then insulation can not be placed up against the fixture, period. This has the potential to cause a fire. The best solution would be to have the old fixture swapped out for one that is rated for insulation contact. Any big box hardware store will have them. Then you can cover the new fixture up with insulation and keep the heat from getting into the attic space.

Back to the first picture of the electric box. That looks like they are caulking the box to prevent air infiltration into the house and heat getting up into the attic. There is a special fire rated caulk for this application, there is also a special version of the cans of spray foam that is fire rated, the foam is dyed red for easy identification and is labeled accordingly.

To get best results use the right stuff. Regular caulk will break down and could potentially be an even worse fire hazard if the box gets hot from a light fixture attached below it inside the house. Regular spray foam is flamable and will burn, don't use it in this situation.

You said the electirc box is warm. Is there a light fixture right below it inside the house? If so then the heat is probably coming from the lightbulbs. Turn the light off and wait for everything to cool off completely, then go back and feel the box. If it is still warm even if the light has been off for a number of hours and has cooled down then you should get a licenced electrician to come and inspect it for other issues. If it is cool then you can proceed to add more insulation over the top os this area to keep the heat from getting into the attic.

What kind of insulation do you currently have?

Get some pictures & post them.

wilsonfrench 01-15-2009 11:22 AM

Quote:

Originally Posted by Dragon (Post 213047)
It would be best if you posted pictures of your actual situation rather than ones found elsewhere. That way comments you receive will be more on target.

In the first picture on your first post you show an electric box, and in the second you show what looks like a large box for recessed lighting. Which one are we talking about?

As stated previously in the comments, if it is a recessed light fixture that is not rated/stamped for "Insulation Contact" then insulation can not be placed up against the fixture, period. This has the potential to cause a fire. The best solution would be to have the old fixture swapped out for one that is rated for insulation contact. Any big box hardware store will have them. Then you can cover the new fixture up with insulation and keep the heat from getting into the attic space.

Back to the first picture of the electric box. That looks like they are caulking the box to prevent air infiltration into the house and heat getting up into the attic. There is a special fire rated caulk for this application, there is also a special version of the cans of spray foam that is fire rated, the foam is dyed red for easy identification and is labeled accordingly.

To get best results use the right stuff. Regular caulk will break down and could potentially be an even worse fire hazard if the box gets hot from a light fixture attached below it inside the house. Regular spray foam is flamable and will burn, don't use it in this situation.

You said the electirc box is warm. Is there a light fixture right below it inside the house? If so then the heat is probably coming from the lightbulbs. Turn the light off and wait for everything to cool off completely, then go back and feel the box. If it is still warm even if the light has been off for a number of hours and has cooled down then you should get a licenced electrician to come and inspect it for other issues. If it is cool then you can proceed to add more insulation over the top os this area to keep the heat from getting into the attic.

What kind of insulation do you currently have?

Get some pictures & post them.


Hi there. I think I am ok with the "shoe box" around the recessed lights...
as for the electrical box...yup, it is warm to the touch when the lights are on...when it is cooled down, what type of insulation can I add?
batts?
blown cellulose
blown fiberglass
...can I tape the electrical box with tuck tape? or cover it with a Vapour barrier? or build a box around it?...
my other kids' bedrooms have the electrical boxes exposed with insulation covering them (one lightbulb in each fixture)...however, my bedroom has two blubs...and seems warm...do I cover this electrical octogon box from the attic side?
will this prevent the heat from getting into my attic?

Dragon 01-15-2009 11:37 AM

I responded to your PM, post it here if you want.


What kind of insulation do you have now? That will factor into what you will use to add more.

wilsonfrench 01-15-2009 01:48 PM

1 Attachment(s)
Quote:

Originally Posted by Dragon (Post 213067)
I responded to your PM, post it here if you want.


What kind of insulation do you have now? That will factor into what you will use to add more.


I have blown fibre now...I am adding blown cellulose...see photo..
basically, I had insulation covering the elctrical ocotgon prior to me moving it...which prompted the original post by me...I just want to be sure it is done right (regardless of what the former owner did)...
the IC rated shoebox is IC-IS rated (whatever)...it is covering the pot lights...and I have covered it with insulation...
see photo for clarification

the roofing god 01-16-2009 06:27 AM

sounds good,just check that IC is the same as The IS stamp with your electrical supply store


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