Which step comes after installing insulation in the sequence?

• A. Seal air leaks
• B. Inspect for gaps and seal
• C. Install vapor retarder
• D. Install interior finish

Answer: (D)

The step being tested is about how the building envelope is sequenced once insulation is in place. After insulation, the next actions focus on making the enclosure airtight and controlling moisture, so the insulation can work effectively. The immediate move is to seal air leaks and inspect for gaps, ensuring there are no pathways for drafts around outlets, penetrations, joints, and around framing. This air-sealing step is essential because even well-installed insulation loses efficiency if air can move through the assemblies.

After sealing, you would typically add a vapor retarder where required by climate and code, to manage moisture moving through the wall or roof assembly. Only after these moisture and air-control layers are in place do you install the interior finish, such as drywall, because finishing materials should come after the envelope is properly sealed and moisture-controlled to avoid trapping moisture or unsealed gaps.

So, the next step after insulation is air sealing and gap inspection, with interior finish coming later in the sequence. If a study answer lists interior finish as the following step, it reflects a broader or different sequencing context, but in standard practice moisture and airtightness come before finishing.