Did this whole exercise at my place a couple years back, so here's what I wish someone had told me up front. Look inside the housing at that label. If it says IC rated, you can bury the can right in the cellulose, that's the whole point of the IC marking. If it says Non IC, the insulation has to stay clear of the housing by whatever distance the label spells out, and you'll want to build a small dam around the fixture so the loose fill doesn't drift in on top of it. Scrap plywood or a strip of metal flashing stapled to the joists works fine for that. The LED trims help your cause since they run much cooler than the old incandescent cans, but the rating on the housing is still what governs the decision. That label is the manufacturer's call, not the insulation crew's judgment call on the day. One extra step before the truck shows up. Pull the trim and seal the gap where the housing meets the ceiling. A can is basicly a hole punched thru your ceiling plane, and blown cellulose is heavy enough to push air through any opening. A bead of caulk or a little foam stops the drafts and keeps dust from sifting down into the room later. Ten minutes per light and well worth it.
A quick guide to blowing cellulose around recessed lights
Oct 16, 2026
Last reply: 1 day ago
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The sealing tip is real too. Before we had the attic done I never noticed drafts, after we had it done the upstairs got noticeably draftier around those cans til I caulked them. Cellulose is heavy and it finds every gap.
On my house half the cans were so old the labels had faded to nothing, so I just figured non IC and kept 'em clear. Cost me a little coverage but cheaper than finding out wrong. Also worth checking if the housing's got any knockouts open to the floor above, mine had one and the blowing crew buried it before I caught it. Sleeping room under that spot was freezing all winter till I went digging.
One thing I'd add on the dams, staple them and then throw a couple of screws in too. My guy's hose caught the edge of one of my plywood dams halfway through the job and a bunch of cellulose dumped right into the can before anybody noticed. Didn't find it till that room's light flickered a week later and I popped the trim to look. Also snap a photo straight down into the attic showing where every can sits before they start, makes finding them again later way easier than guessing off the ceiling below.
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