# vapor barrier and slim LED recessed fixture



## Mac Moonfire (Aug 9, 2019)

Hi,
How to obtain a seal at the vapor barrier with those slim LED recessed fixtures?
Here's an example of the product: https://www.lotusledlights.com/recessed-lighting/4-inch/9w-super-thin

The poly is cut at the drywall stage and it creates an unsealed penetration through the vapor barrier.

Insight anyone?
thanks


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## mark handler (Aug 10, 2019)

T*hey are Air-Tight, seal to Vaper-barrier or run VB over the top or install a rated box above the fixtures in the ceiling.*


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## tmurray (Aug 12, 2019)

We typically see vapour barrier tape around where the wire penetrates the vapour barrier or a vapour barrier box around them.


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## Mac Moonfire (Aug 13, 2019)

Thank you for the answers, what I have seen so far are the transparent plastic boots. I'm not convinced it creates a seal at the vapor barrier. I've even caught some of them taped in a manner that allows air flow
I'll follow up on that and will try to come up with something.
Thanks


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## jail (Mar 6, 2021)

I can't find in the IRC where vapor barriers are required in ceilings. Everything I find in the code about required vapor barriers are about walls and under slabs.


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## Keystone (Mar 6, 2021)

jail said:


> I can't find in the IRC where vapor barriers are required in ceilings. Everything I find in the code about required vapor barriers are about walls and under slabs.



Terminology, vapor barrier, may be incorrect. I believe what’s meant is the buildings thermal envelope penetrating the ceiling air barrier.


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## jail (Mar 7, 2021)

Yes, an air barrier is required. Not a vapor barrier. Not sure of the definition an "air barrier"


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## mp25 (Mar 7, 2021)

2018 IECC Table 402.4.1.1 Where a recessed fixture penetrates the air barrier it shall be sealed or gasketed to the finish. Fixture shall be air thight and IC rated.

Vapor barrier is usually not continuous - the kraft paper used on insulation is never taped together nor does it have to be - at least in my area.


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## mark handler (Mar 8, 2021)




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## steveray (Mar 11, 2021)

R702.7 Vapor retarders. Class I or II vapor retarders are
required on the interior side of frame walls in Climate Zones
5, 6, 7, 8 and Marine 4.
Exceptions:
1. Basement walls.
2. Below-grade portion of any wall.
3. Construction where moisture or its freezing will not
damage the materials.

R805.1 Ceiling installation. Ceilings shall be installed in
accordance with the requirements for interior wall finishes as
provided in Section R702.


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## Teeshot (Mar 16, 2021)

The fixture is listed at Air Tight (AT) which would typically allow it to penetrate the ceiling membrane without the need for additional measures, unless the AHJ has their own requirements.


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