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.