Fixture styles and installation

Residential construction lighting trends through much of the 2000s and into the early 2020s consisted primarily of variations of canned style pot lights and their ability to flood spaces with light with minimal fixture assembly extending into the living areas. Although their bulky bodies were typically hidden in the framing assemblies, they weren’t without some drawbacks. Framing limited to where you could install them, and as more energy efficient homes were being built, these became less and less feasible to keep them properly sealed in unconditioned attic spaces.

Developments in electrical device boxes moved to the gasketed and flanged type, these offered the most options to deal with multiple lighting styles while keeping the idea of your building envelope generally intact. These electrical boxes replaced having to depend on plastic poly hats and allowed builders to move towards lighting that still offered the low profile, near flush mounted look of a pot light, in a surface mounted disk light. All while avoiding the bulky bodies of the canned style and headaches they brought with building envelope failure for builders when installed in a high-performance homes.

Ultra low-profile, recessed light fixtures, while used mostly in custom home settings, offer the ultimate in flexibility with installation and lighting design. Their low-profile body can be recessed for a flush look, and because of their depth, are marketed as capable of being installed directly below framing and trusses. Consideration must be made to accommodate for the LED driver / junction box that comes with these which typically is left adjacent to the fixture cut out in the ceiling void.

Surface mounted disk style.
Surface Mounted Disk Style
Canned style pot light.
Very low profile recessed disk style fixture.
Typical flanged device box for installation.
Typical Flanged Device Box
Typical accompanying poly hat for vapour barrier tie in.
Rough in stage using large poly hats, note they are missing backing on all 4 sides.

What we’re seeing in the field

All types of installations come with considerations, and clearly defining each trade’s responsibility and sequencing is crucial in keeping the continuity of the vapour barrier as intact as possible. This is to minimize cases of attic rain and moisture damage to finished surfaces. Air loss at ceiling penetrations is a common culprit in Alberta.

Along with air loss and minimizing air leaking into the attic, considerations should also be taken to accommodate large poly hat installation, over either canned pot lights, recessed speakers or mechanical bath fans. Insulation depth should remain consistent overtop of these installations. A hot /cold transfer zone could develop where interior moisture is condensing on the finished surface of these cold spaces or inside the poly hats themself, leading to damp areas and moisture damage.

Low profile recessed disk lighting offers incredible flexibility, but educating your designers and trades to understand the potential concerns with vapour barrier tie ins should also be considered. From a design standpoint, installing these fixtures directly below a roof truss can open up a variety of lighting options, but how will your insulator tie this into the building envelope assembly while still accommodating for the wiring penetrations and the LED driver?

Low profile recessed disk, air leakage and insulation deficiency. The low profile design allows installation below truss but is difficult to tie in vapour barrier.
Canned style pot lights, insulation deficiency.
Typical flanged device box, air leakage.


It all comes back to making your trades aware of the importance of the building envelope continuity, the hows and the whys. Does your electrician know how to minimize penetrations and, more specifically, the size of penetrations in the vapour barrier. The poly hats they’ve just installed, have they installed this so there is backing on all 4 sides so the insulator can have proper compression with his acoustical sealant? Have they minimized the wire entry into the poly hat, and then does your insulator know to confirm this wire entry isn’t excessive and to repair as required? Is the depth of insulation above these oversized poly hats sufficient to prevent moisture being trapped inside? These are questions we should be having when installing these types of assemblies into new homes.

When installing flanged type electrical boxes, care must be taken to keep the self-sealing wire entry gaskets intact. These boxes are the best option in general as they are built as a one-shot tie into the vapour barrier assembly, no added poly hat is required and they come with gaskets installed to help with the joint compression. However, if the gasket is damaged or the flange broken, the assembly may now be compromised and in turn, the building envelope assembly. There is also concerns that the foam gaskets may not serve to protect against air filtration over time as our experts have seen deterioration occur. These gaskets should also be backed with sealant to ensure their durability.

More and more, as building science and government gears towards ultra efficient housing, limiting ceiling penetrations all together may become the norm, moving these electrical fixture boxes to interior walls where possible. Minimizing wiring and mechanical penetrations into these unconditioned spaces is another method to combat challenges with attic rain, where all unnecessary electrical wire is run through the interior spaces of the home. These wires would run through interior walls or the lower floors. Ultimately, keeping up with trends and adapting to them becomes all of our responsibility, building practices considered typical even 10 years ago, often times won’t fly today.

Excessive wire entry at oversized poly hat left unsealed.
Flanged electrical box, installed with broken flange.
Stains around low-profile disk light assemblies.
Attic with oversized penetrations, insulation is level, but no accommodations made to keep consistent depth above these poly hats..
Stains on finished ceiling, product of attic rain.
Thermal image of attic rain, bonus room with low-profile disk lights installed.
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The content provided in this blog is for general information purposes only and nothing contained herein should be taken or relied upon as legal advice. Although every effort is made to ensure the accuracy of information shared on this blog, the information may inadvertently contain inaccuracies.