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Spraying over recessed can lights Post New Topic | Post Reply
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Posted: May 13, 2009 09:20 AM
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Spraying over recessed can lights
I'm going to be spraying down on to an existing ceiling which has several can lights using 1/2# foam. The lights are insulation ready, but the manufacturer says not to spray directly to the cans. Could we wrap the cans in fiberglass or other material & spray over the top creating the envelope? What other material might work?
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mason
Posted: May 13, 2009 10:51 AM
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SPFA recommends that you box those lights in rather than insulating them with fiberglass. This would be the conservative approach. |
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Posted: May 14, 2009 01:32 AM
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a "real-world" approach... wrap em in a liberal layer of filterglass and spray the foam over the glass,,, we have over a gazzillion cans done this way with no blinkers or faults,,, we have a half-a-gazzillion cans sprayed directly to them in our area with the same results... not sure why the spfa recommends building boxes out of drywall scraps or similar products...it seems they think all lids are 23x50 flat with nothin but a light or two up there,,,,guess they havent foamed any triple tray master bedrooms with multiple low voltage type cans built into the trays,,,or maybe the wonderfull applicaton where the can was "cut into" a rafter truss being right up in this thing,,,the last small home we did had 63 cans on the main level,,,we would have built boxes for 3 days,,,and can we do it cheap???? i think the spfa needs to rethink its position and maybe be a little less "specific" as to its recomendation of a layer of interference between the fixture and the foam... i know i shouldnt,,but here goes,,, i think the spfa should back off installation "specification recomendations" in the residential/commercial industry,,,until they better learn how this product is used INSIDE a structure,,maybe a study or 2 on the performance of foam so we dont have to sell 3x as much to meet a prescriptive r value,,,so why the heck can the foil folks sell performance value and we cant????or the icf folks,,,or,,,or,,, opps i lost my direction,,,,hee hee wrap em in glass and spray over it... get in,,,get out,,get your check sign this one... renigade hillbilly foamer :) |
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Frank Bood
Posted: May 14, 2009 06:00 PM
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Im with dude on this one its what we have do and have done for a long while and no issues. |
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SPFer
Posted: May 15, 2009 06:51 AM
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We were wrapping the cans with fiberglass for a long time, but we have recently switched to putting rigid board up against the sheathing above the cans and spraying to the rigid. I get different thicknesses of rigid and cut them down to 14" on the tablesaw. Then, the guys glue them up. We make sure to spray to the rigid, eliminating any thermal break. You lose some R-value, but when we were wrapping the cans with fiberglass, I had noticed some drafts still coming through the cans. Not anymore. Costs alittle more than the fiberglass, but takes less time. |
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Posted: May 15, 2009 10:30 PM
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caddis,,if i am reading this right,,you are referring to a "cathedralized" ceiling with the limited space between the can top and the roof sheeting above,,,if so,,you betcha!!!some times there is limited space between the can tops and the decking,,say in a 2x8 or sumpin like that,,and the rigid as a void filler works top shelf!!! but we were talkin about spraying down to the lid...an existing flat lid,,,so hence the filterglass wrap...you can cap these lites really well,,, 'dude |
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roberto casini
Posted: Aug 18, 2010 05:06 PM
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Tenmat has developed a product specific for this application. It's a cover made out of mineral wool that sits on top of the light keeping the foam at safe distance. |
