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Hi,
In the 2nd floor ceiling we have a number of canister lights. I was up in the attic and noticed that the insulation doesn’t come up to the can, I assume for fire reasons. Anyone have an idea on what materials to use to construct a box (also what space to leave around the can) so I can put some insulation up there? I thought of some sort of fireproof shingling might do the trick, but what to use?
Thanks
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First thing is to check if your light fixture is a Thermally Protected IC rated light fixture. If it is you can put fiberglass insulation up to it and over it. Another thing you could do is build a box out of a rigid foil faced insulation board, like 2" think, and put it together with foil tape over the unit, which will give you a high r-value right around the light fixture, adhere it down to the ceiling board with silicone, and then put fiberglass insulation around and over the box. I did this to a house I built and it worked great!!. This also works to put a continuous vapor barrier around the light. P.S. make sure that you are working with a IC Rated Fixture first, it should say if it is one inside the fixture. If it isn't a Thermally Protected Unit it does need somewhat of a buffer space around it for the cooling off of the fixture. Hope this helps.
* Steve Zerby "Vapor Barrier" 9/2/99 9:51am
*Jim, Thanks, that's the very idea I was looking for. I suppose 4" is enough clearance around the canister, or what did you use.Don
*Mongo,Thanks for the archive, I didn't find that one. The problem is the canisters aren't IC (?) rated and there are 9 of them between a bedroom, bath and hall so replacement is less desireable. I'm going to try Jim's idea.Don
*Don...I would use drywall instead...I would not put a foam cap on them as I would not think it is fire safe...And it probably is frowned upon by fire inspectors and the makers of the lights...If you want to put the foam over the drywall, then you might be better protected...Just my opinion near the stream,ajI push track lights now instead of recessed...
*AJ,Thanks for the idea. How much space should I leave around the light? I guess I'm concerned the paper on the drywall will smolder. How about dura-rock, harder to work with, but...Lake George eh, a little cold up there? Are you near Bolton Landing, The Sagamore? Took my Dad up there for a golf weekend back in '91. Great place.Don
*Don, I'd much prefer to see you use drywall boxes instead of those made from RFBI for boxing IC-rated cans.I couldn't, with a clear conscience, recommend boxing non-IC fixtures...especially with RFBI.
*b WBA At Your ServiceDon,i careful, careful, carefulThese fixtures build up lots of heat and you will be relying on the thermal protector to shut off the light in case of an overheat. They don't always work. I would tell you to check with the light manufacturer, but they will tell you DON'T do it. I have seen this done, and I don't think 4 inches is enough. You really should build one, install it and then check temperatures inside the box, with the highest wattage bulb that could be put in the fixture. This could be a fire hazard.
*Don, I agree with these guy's. Don't put a box around it, if it isn't a IC Rated Unit. I had IC Rated Units, and I still left at least a 4" space all around it. I would replace the units to IC Thermally Protected Units. Its a lot cheaper than replacing your home or a life. Whoever installed your lights should have used IC Rated lights, if it was in a area that needed insulating.
*Ya....I painted the entire Sagamore back in my college days...After working all day...we would head over to the dorm for a Cruz pack...which was a bag of iced beers that this guy Cruz sold on the side...Two beers after sweating all day and we were flying!I dock my boat near the Sag...Did the year 2000 thing there in black tie and all...Come on back up here as we still have fun around here...skiing in the morning.near the stream which runs into Beautiful Lake George,aj
*Don, check and see if the same manufacturer's ICT light will fasten in your original housing's hanger. If so, you can change em all over from below. Best of luck
*Jim, Cal, AJ,Tim,Mongo,Thanks for the feedback. I didn't get up into the attic this weekend. Doing the snow removal from the roof job from last weekend's storm (in NJ). I had some ice 'damning'which caused a couple of small but aggrivating leaks which caused me to think the canister lights were a major contributer. Attic is well ventilated and insulated so the next step is to solve the light heat leak situation. I'll be sure the lights are IC rated before insulating, and if not then look into replacement. They are accessable from above so we'll see. I'll add any new info in subsequent posts.Thanks All.
*Don, there is an article in the current issue of Home Energy magazine (www.homeenergy.org) that addresses your problem. The authors built a drywall box around a non-IC-rated fixture, leaving 3-in. of clearance, and measured temperatures in several scenarios. There is too much info in that article to regurgitate here, but I strongly suggest that you get yourself a copy of Jan/Feb 2001 Home Energy. Try calling them at (510) 524-5405 to see if they'll fax you a copy of the article. Try promising to subscribe, and say that an FHB editor told you that you need to get the article, A Recessed Can of Worms, so that you don't burn down your house. That might not help you, but it can't hurt. Then, do subscribe -- you'll be keeping your word, and they're a great magazine for anyone interested in understanding how houses work.Andy
*Andy,Thanks very much. I haven't gotten to the job yet, last Sat. was my monthly day at HfH, Sunday the Giants game with one of my sons, Monday ("a day off") opening pandora's box in a bathroom where the ice dams did more damage than I expected (I'm going to learn how to plaster over greenboard). The canisters are next.Don
*We installed IC rated cans in our new church once, and they just put the insulation over the top of them. Worked fine, until they started randomly turning off, then back on, then off again during the preacher's sermon! So they work, but sure can be irritating.So I'd leave an airspace around them, even if they are IC rated.What do ya'll think about making a plywood box? The foam board is supposed to be covered with something, I think. Check for flammability before using it to make boxes, especially over lights.
*Crusty,Thanks for the feed back. I'm not sure but I don't think these lites are IC rated (I haven't had time to get up in the attic and check). I'm going to try what Andy suggested (see post 13)and I'll leave a folllow-up when I do.Thanks,Don
*Andy,Called Home Energy magazine, they are sending a complimentary trial issue, thanks for the suggestion.Don
*Excellent. They aren't glitzy, but I respect their journalism.Andy
*I had the same problem in an "inherited" house. I had 5 non-IC lights in an attic. I found out that new IC units were $20/unit and decided to skip the headache of "turning a fix into a fuse"... and burning down the house.If you do box in the existing lights, I'd use sheetrock & non flammable adhesive (post drying) for 2 reasons: first, you wouldn't need "framing" if it's glued together, and second, It makes the box airtight.
*Skunk,Thanks for the idea. My main concern is how much space to leave around the canister so the sheetrock paper doesn't smolder. Hopefully the mag. article Andy suggested (see post # 13)will give me an idea. What's your suggestion? To hold the corners together I thought a strip of corner beading inside and outside the sheetrock with screws holding it together, but I like your adhesive idea.Thanks
*Related question: Is blown glass any different from blown cellulose in regards to burying IC cans in an attic? I also am curious if a bunch of IC cans are all new, and buried in fluff, is it reasonable to assume that they are cool enough since the thermal protectors never trip off in use? Thanks for any input.Bill
*I'd bet it is different. The fibreglass will allow air to circulate, thus cooling the fixtures. The cellulose does not allow the air to circulate so easily and depending on the density of the cells, there may be nearly zero circulation.
*Thanks, Bill. To extrapolate from your post, cellulose inhibits convective losses better than fiberglass. Do I have that right? It seems there are advantages to it which I did not know. Many years ago I used it on a house I built for myself because it has higher R-value per inch (not a lot), has recycled content, and because I strongly dislike glass fibers in my clothing, skin, or lungs. Years later I learned of the fire safety issues. What I really want to know is why no one markets a batt form of cellulose insulation in this great country? Even with the failings of the batt format, it would offer advantages over the "pink death" we all too often end up using.Bill
*I went to "the box" this weekend and made sure to take a look at the IC vs non-IC facts. It seems as though the IC rated lights are also limited to a 75 watt light source (non-IC can use up to a 150 watt bulb). That alone will limit the amount of heat that accumulates.If I were going to build the boxes out of sheet rock (1/2" ?). I would give at least 4 or 5 inches of space around the fixtures. So width wise, 14 to 16 inches (4 or 5 + 6 + 4 or 5 = 14 or 16), and length wise anywhere between that and the 22.5 inch dimension of a rafter space (but enough that I could get insulation between the rafter and the box easily). Height, use the height of the can and add 4 to 6 inches taking into count the height of the roof above the lights.I would probably assemble the sides first, using a caulk/adhesive in the corners (shaped with a wet finger to make sure there are no air leaks) and a 1x2 ribbon at about the center of the box's height around the outside to hold it together as the adhesive sets up. Put a screw in the center of the sheet rock and a screw in each corner (pre-drilled) connecting the 1x2's. So if your making a 14 x 18 box, use sheetrock side panels that are 1 inch larger on the overlap sides, and 1x2's that match one side and are 1 1/2 inches larger (3/4 inch overlap) for the overlap sides. Mark the bottom edge (against your work table) as "up", because it will be the flattest possible surface to mate the top panel with.After the sides set up, take the top panel and position the box on it with the "up" marking down to the top panel. Mark the inside edges with a pencil, remove the box and lay a bead of adhesive just outside the line. Now set the box into the adhesive with good pressure and use a wet finger to shape the caulk again in the seam and let it sit to cure. When they dry, they should be solid. I'd leave the 1x2's attached to make them easier to handle, and not as fragile.BTW, I just finished insulating the attic where those lights are located (40 year old house that only had 3 1/2 inch R-13!!, If my dad had beefed up the isulation back then... he could have saved the $14,500 he paid for the house by now!).I insulated up to the new lights with R-13 batts and replaced any damaged stuff (roof trusses made of 2x4's) to even-up the base layer without tearing out all the old insulation. I then went perpendicular with R-19 unfaced batts, hoping to minimize corresponding seams and completely burying the lights. I have yet to see them over-heat and turn off.The heating system has been kicking on less, and there is snow left on the roof (most of the neighbors have stripes of roofing showing by now, if not completely bare. Now, hopefully the energy costs reflect my hard work!
*Don, Build a insulated box out of foil faced insulation and tape the sides and top together with foil tape, and then lining the inside of the box with 5/8 gypsum board using a adhesive glue. You will then have a insulated, air tight, vapor barrier sealed, fire proof box.
*Skunk & Jim,Thanks both for the solid feed back. Just got my "complimantary" edition of HomeEnergy mag.(see post 13) They ran a complete test from what bulbs (reflector not regular bulbs) to use, to how to build the box, to summer heat simulation. I'll incorporate the info from the article as well as these posts. Don't want to hear fire sirens.Don
*Bill Brennen - I don't know of any fire safety problem with cellulose. Walls insulated with cellulose burn through slower than ones with fibreglass in lab tests.Plus the blown cells make perfect contact with the air barrier - well - perfect. Batts never would.
*Bill Connor,Right you are. When I re-read my post tonight, I realized it appears that I have bought into the "glass is better because it cannot burn" fallacy. What I was trying to say was that it was a number of years after I chose cellulose for my own home, when I finally learned of the tests proving that cellulose inhibits flame spread far better than fiberglass does. When I first used it I figured it would be no worse than glass, and was very pleased to later learn that I had made an even better choice than I knew at the time. Andy Engel mentions his experience with the sound deadening properties of cellulose, and I also remember reading somewhere that it is opaque to IR radiation, whereas the fiberglass is transparent to IR, which of course makes a huge difference in the summer. The attic with the glass has IR rays that leave the roof sheathing and don't stop until they see the ceiling rock. The cels attic stops the rays in the first inch of fluff on the top. Big difference. I love the intelligent discussions on this board. I have learned so much here.BillP.S. Although cellulose batts would be inferior to blown-in cels, they would still allow one to obtain SOME of the cellulose benefits without having to go through the extra steps involved with getting someone to blow the job. I still end up using FG batts in small jobs because of convenience. Often there is just one wall of a bathroom, so I batt it and rock it.
*I recently saw in an ad for Cocoon cellulose blow in insulation where it looks like they used a short section of metal duct. After giving it some thought I thought it was a darn good idea. I roughly estimated that they probably were using about a 12" diameter pipe (the can is roughly 6" and 6" to maintain a 3" insulating space around the fixture, think of a donut where the hole is the can itself. Thought you might like the idea, solves most of the issue concerning most of the other materials suggested too i.e. flammability, ease of construction etc. You could pick up a few unassembled sections at the home center and cut them to the length. Thought I would just pass on the idea.
*Tim BThamks for your thought. The article in Home Energy (see post #13)frowned on them because they "act just like chimneys". They did an extensive test and recommended 1/2in sheetrock boxes with insulation up to the sides but not on top. If you're interested in the article let me know and I'll fax a copy to you.Don
*I have the same problem regarding having lots of light cans on the second floor, and I have been reading this post in hopes of a fix. I have all IC housings with fiberglass insulation layed over the cans. I first made a box, but we are talking 25 or so boxes to build! So I tried something else in one room. First off I couldnt believe how much air these things leak, I could remove the bulbs easily because they were cool from the air leakage. After removing the bulb I could feel the cold air coming in. I used metal tape to seal all the small holes in the can from the inside, and also the sheetrock to can edge behind the baffle. No more air leakage, the difference was amazing. The back of the cans are still open to cool air for cooling. I tried this with one room (4 lights) and left them on for over 16 hours straight with no overloads tripped, and the backs of the cans stayed cool. It was definately a lot quicker than building the boxes, and I plan on doing the rest of the cans this way. I am not telling anyone to try it, but it is working for me. Gotta have a disclaimer somewhere!
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Hi,
In the 2nd floor ceiling we have a number of canister lights. I was up in the attic and noticed that the insulation doesn't come up to the can, I assume for fire reasons. Anyone have an idea on what materials to use to construct a box (also what space to leave around the can) so I can put some insulation up there? I thought of some sort of fireproof shingling might do the trick, but what to use?
Thanks