New STANDATA: Rowhousing Buildings with Five or More Dwelling Units

February 2, 2025

Purpose

To clarify the application for professional involvement for building services and systems for buildings classified as
residential occupancy identified as a multiple-family dwelling containing five or more dwelling units in a rowhouse
configuration.

Discussion

Division C, Subclause 2.4.1.1.(1)(b)(ii) of the National Building Code – 2023 Alberta Edition does not require
professional involvement where a multiple-family dwelling contains four dwelling units or less. Division C,
Sentence 2.4.1.1.(3), which applies to buildings other than those described in Sentence (1), therefore requires
multiple-family dwellings with five or more dwelling units to have the drawings and specifications authenticated by
one or more registered professionals as applicable.

Division C, Sentence 2.4.1.1.(3) has been interpreted by some to mean that every aspect of a residential
occupancy that is a multiple-family dwelling containing five or more dwelling units in a rowhouse configuration,
must be designed by a registered professional qualified to engage in each respective area of the practice of
architecture and engineering.

When in a rowhouse configuration (no dwelling unit above another), many building services are provided
separately to each dwelling unit, or systems are contained wholly within each dwelling unit, and thus, each service
or system is designed the same way they would be for a detached house or for rowhousing buildings with four or
less dwelling units. It is not the intent of the code to require authentication by one or more registered professionals
for all services or systems serving (or contained wholly within) an individual dwelling unit where there is no
dwelling unit above another dwelling unit.

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