Who is primarily responsible for achieving air tightness requirements from a contract perspective?

The builder is primarily responsible for achieving air tightness requirements from a contract perspective because they are typically the entity directly involved in the construction process. The builder's role encompasses the implementation of construction practices that meet the specifications outlined in the contract. This includes ensuring that the building envelope is constructed to the specified airtightness standards.

As part of their responsibilities, builders often need to coordinate with subcontractors and suppliers to select appropriate materials and techniques that enhance air sealing. Additionally, they are generally responsible for any remediation work if the initial airtightness testing reveals that the building does not meet the required standards.

While the project manager may oversee the overall project, the builder's direct hands-on involvement in the construction and compliance with building codes and contract specifications places them as the primary party responsible for achieving air tightness. The owner's representative and compliance officer may assist or review, but their roles focus more on oversight and compliance rather than direct responsibility for construction outcomes.