Recessed Lights Under Attic Insulation: IC-Rated, Airtight or Covered?
In climate zones 1 to 4 and 8 to 16, recessed cans in an altered attic ceiling are buried under insulation to the same depth as the rest. A can not rated for insulation contact is replaced or fitted with a fireproof cover, not walled off with a dam. Existing cans do not have to be airtight.
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When the attic work reaches the cans
The compliance manual ties the attic rules to a specific act: existing insulation is replaced, new insulation is added, or the ceiling plane is replaced. A new duct system with its air handler in the attic does the same. Section 150.2(b)1J then lists the recessed-light step beside air sealing and the ceiling R-value. The carve-out is zones 1 to 4 and 8 to 10 where the ceiling already has at least R-19. A ceiling holding R-38 skips the whole attic list.
Reading the can
Remove the lamp and look inside the housing for a UL mark reading IC. Slits or holes mean it is not IC rated, and a doubtful label is treated as not rated. A non-rated can has two routes: replace it with an IC-rated retrofit housing, or cap it with a fire-rated dome or box. The cover works only if the fixture has a thermal switch; if you cannot confirm one, assume none. Products that dam the can without letting insulation cover it do not satisfy the rule.
Airtight is a separate question
The attic rule does not make old cans airtight. Airtightness arrives when luminaires are entirely replaced: under Section 150.0(k)1C the new housing has no screw-base socket, carries a label showing leakage under 2.0 cfm at 75 Pa, and is gasketed or caulked to the ceiling. An IC-rated can that leaks may take a retrofit trim kit instead.
When none of this applies
Adding two cans to a kitchen is a lighting alteration, not a ceiling alteration, so the attic list is not pulled in (see kitchen remodels and replacing light fixtures). The building department checks these prescriptive items; an ECC-Rater does not. In a new home or large addition under quality insulation installation, the rater does verify that fixtures are IC rated, airtight, sealed and covered.
The other attic steps are on attic insulation for remodels. For a compliance report, see our residential reports.
Common Title 24 Questions
- When is Title 24 required for a home?
- Does a remodel need Title 24?
- Does a room addition need Title 24?
- What plans are needed for a residential Title 24 report?
- How much does a residential Title 24 report cost?
- How long does a residential Title 24 report take?
Frequently Asked Questions
Not to meet the rule. A dam leaves a bare patch around each can. The code wants insulation over the fixture, so the can is replaced or capped with a fireproof cover.
A thermal switch. The manual allows a dome or box cover only on a fixture that has one, and says to assume none if you cannot tell.
Explore Insulation
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- Title 24 for an Older Home With Unknown Insulation
View all Insulation guides → · Windows and Building Envelope · Title 24 guide