Building Enclosure Requirements for Multiunit Residential Buildings. Specific building enclosure requirements apply when constructing or rehabilitating a multiunit residential building, or when converting a multiunit residential building to condominium units. ?A building enclosure is the part of a building that physically separates the exterior environment from interior environments, and which weatherproofs, waterproofs, or otherwise protects the building or its components from water or moisture intrusion.
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Definition. A multiunit residential building is defined as a building with more than two attached dwelling units.?

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Exclusions. A multiunit residential building does not include hotels, motels, dormitories, care facilities, floating homes, buildings with attached dwelling units each on a single platted lot, buildings subject to a recorded irrevocable sale prohibition covenant, or buildings with 12 or fewer units that are no more than two stories. ??
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Design Requirements. Building enclosure design documents must be submitted with any application for a building permit for the construction of a multiunit residential building. ?The documents must be stamped by an architect or engineer and must address waterproofing, weatherproofing, and other protections of the building from water or moisture intrusion. ?A building department may not issue a building permit unless the design documents have been submitted.
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Inspection Requirements. The building enclosure of a multiunit residential building must be inspected during initial or rehabilitative construction. ?The inspection must determine, through periodic review, whether the building enclosure construction complies with the design documents. ?The inspection must include testing of windows and window installations for water penetration problems.
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Building enclosure inspections must be performed by a person who has training and experience in design and construction of building enclosures, who is free of improper interference or influence, and who has not been an employee of the developer. The inspections may be done by the architect or engineer who prepared the design documents or who is the architect or engineer of record on the project.
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A building department may not issue a certificate of occupancy for a multiunit residential building until the inspector submits a building enclosure inspection report certifying that the building enclosure was inspected during construction and that the building enclosure was constructed in substantial compliance with the design documents.
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Inspection Requirements for Residential Condominium Units. A residential condominium unit in a multiunit residential building may not be sold without meeting the building enclosure design and inspection requirements for construction of multiunit residential buildings. These requirements do not apply if the building enclosure meets certain alternative inspection requirements.

Buildings with 12 or fewer units that are no more than three stories are excluded from the definition of multiunit residential building if one story is utilized for above or below ground parking, or retail space.